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Sample records for thin carboxylic acid

  1. Di- and tri-carboxylic-acid-based etches for processing high temperature superconducting thin films and related materials

    International Nuclear Information System (INIS)

    Ginley, D.S.; Barr, L.; Ashby, C.I.H.; Plut, T.A.; Urea, D.; Siegal, M.P.; Martens, J.S.; Johansson, M.E.

    1994-01-01

    The development of passive and active electronics from high-temperature superconducting thin films depends on the development of process technology capable of producing appropriate feature sizes without degrading the key superconducting properties. We present a new class of chelating etches based on di- and tri-carboxylic acids that are compatible with positive photoresists and can produce sub-micron feature sizes while typically producing increases the microwave surface resistance at 94 GHz by less than 10%. This simple etching process works well for both the Y--Ba--Cu--O and Tl--Ba--Ca--Cu--O systems. In addition, we demonstrate that the use of chelating etches with an activator such as HF allows the etching of related oxides such as LaAlO 3 , which is a key substrate material, and Pb(Zr 0.53 Ti 0.47 )O 3 (PZT) which is a key ferroelectric material for HTS and other applications such as nonvolatile memories

  2. Carboxylic acid reductase enzymes (CARs).

    Science.gov (United States)

    Winkler, Margit

    2018-04-01

    Carboxylate reductases (CARs) are emerging as valuable catalysts for the selective one-step reduction of carboxylic acids to their corresponding aldehydes. The substrate scope of CARs is exceptionally broad and offers potential for their application in diverse synthetic processes. Two major fields of application are the preparation of aldehydes as end products for the flavor and fragrance sector and the integration of CARs in cascade reactions with aldehydes as the key intermediates. The latest applications of CARs are dominated by in vivo cascades and chemo-enzymatic reaction sequences. The challenge to fully exploit product selectivity is discussed. Recent developments in the characterization of CARs are summarized, with a focus on aspects related to the domain architecture and protein sequences of CAR enzymes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Nitric Acid Dehydration Using Perfluoro Carboxylate and Mixed Sulfonate/Carboxylate Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Richard L. [Colorado School of Mines, Golden, CO (United States)

    2004-09-01

    Perfluoro ionomer membranes are tetrafluoro ethylene-based materials with microheterogeneous structures consisting of a hydrophobic polymer backbone and a hydrophilic side-chain cluster region. Due to the ionomer cluster morphology, these films exhibit unique transport properties. Recent investigations with perfluoro sulfonate and perfluoro sulfonate/carboxylate composite polymers have demonstrated their value in the dehydration of nitric acid and they show potential as an alternative to conventional, energy intensive unit operations in the concentration of acid feeds. As a result, investigations were conducted to determine the feasibility of using pure perfluoro carboxylate and mixed perfluoro sulfonate/carboxylate films for the dehydration of nitric acid because of the speculation of improved water selectivity of the carboxylate pendant chain. During the first phase of these investigations the effort was focused on generating a thin, solution cast perfluoro carboxylate ionomer film, to evaluate the general, chemical and physical characteristics of the polymer, and to assess the material's aqueous transport performance (flux and nitrate separation efficiencies) in pervaporation and high-pressure environments. Results demonstrated that generating robust solution-cast films was difficult yet a number of membranes survived high trans-membrane pressures up to 700 psig. General characterization of the solution cast product showed reduced ion exchange capacities when compared with thicker, ''as received'' perfluoro carboxylate and similar sulfonate films. Small angle x-ray scattering analysis results suggested that the solution cast carboxylate films contained a small fraction of sulfonate terminated side-chains. Aqueous transport experimentation showed that permeate fluxes for both pure water and nitric acid were approximately two orders of magnitude smaller for the carboxylate solution cast membranes when compared to their sulfonate

  4. Carboxylic acids as substrates in homogeneous catalysis.

    Science.gov (United States)

    Goossen, Lukas J; Rodríguez, Nuria; Goossen, Käthe

    2008-01-01

    In organic molecules carboxylic acid groups are among the most common functionalities. Activated derivatives of carboxylic acids have long served as versatile connection points in derivatizations and in the construction of carbon frameworks. In more recent years numerous catalytic transformations have been discovered which have made it possible for carboxylic acids to be used as building blocks without the need for additional activation steps. A large number of different product classes have become accessible from this single functionality along multifaceted reaction pathways. The frontispiece illustrates an important reason for this: In the catalytic cycles carbon monoxide gas can be released from acyl metal complexes, and gaseous carbon dioxide from carboxylate complexes, with different organometallic species being formed in each case. Thus, carboxylic acids can be used as synthetic equivalents of acyl, aryl, or alkyl halides, as well as organometallic reagents. This review provides an overview of interesting catalytic transformations of carboxylic acids and a number of derivatives accessible from them in situ. It serves to provide an invitation to complement, refine, and use these new methods in organic synthesis.

  5. Novel Polymers with Carboxylic Acid Loading

    DEFF Research Database (Denmark)

    Thomsen, Anders Daugaard; Malmström, Eva; Hvilsted, Søren

    2006-01-01

    Click chemistry has been used to prepare a range of novel polymers with pendant carboxylic acid side groups. Four azido carboxylic acids, either mono- or difunctional and aliphatic or aromatic, have been prepared and thoroughly characterized. Extensive model reactions with 1-ethyl-4-hydroxybenzene......, the simplest model for poly(4-hydroxystyrene), and the four azido carboxylic acids have been conducted to establish the proper reaction conditions and provide an analytical frame for the corresponding polymers. Poly(4-hydroxystyrene) moieties in three different polymers—poly(4-hydroxystyrene), poly(4...... the polymers in general exhibit [when poly(4-hydroxystyrene) is a substantial part] significant changes in the glass-transition temperature from the polar poly(4-hydroxystyrene) (120–130 °C) to the much less polar alkyne polymers (46–60 °C). A direct correlation between the nature of the pendant groups...

  6. Carboxylic acids from West Siberian crudes

    Energy Technology Data Exchange (ETDEWEB)

    Zhil' tsov, N.I.; Ershov, V.A.; Zakharova, T.F.

    1982-09-01

    The concentrates of acidic compounds were recovered from the raw crudes by extraction with a 2% solution of potassium hydroxide in 50% ethanol; the concentrates were then treated to remove neutral substances present as impurities and were separated into phenols and carboxylic acids by means of silica gel modified with caustic. The methyl and trimethylsilyl (TMS) esters of the carboxylic acids were analyzed by chromatography/mass spectrometry. It is assumed that in the West Siberian fields, along with catagenic processes, microbiological degradation processes are taking place. After a sample of Fedorovsk crude had been exposed to the bacterial action (60 days at 32/sup 0/C) of an accumulated culture of sulfate-reducing bacteria, followed by dehydration of the sample, the relative content of straight-chain fatty acids with an even number of carbon atoms had increased. There was a sharp increase in the contents of palmitic, palmitoleic, and oleic acids, which are characteristic products of the metabolism of microorganisms.

  7. Ketone Formation from Carboxylic Acids by Ketonic Decarboxylation: The Exceptional Case of the Tertiary Carboxylic Acids.

    Science.gov (United States)

    Oliver-Tomas, Borja; Renz, Michael; Corma, Avelino

    2017-09-18

    For the reaction mechanism of the ketonic decarboxylation of two carboxylic acids, a β-keto acid is favored as key intermediate in many experimental and theoretical studies. Hydrogen atoms in the α-position are an indispensable requirement for the substrates to react by following this mechanism. However, isolated observations with tertiary carboxylic acids are not consistent with it and these are revisited and discussed herein. The experimental results obtained with pivalic acid indicate that the ketonic decarboxylation does not occur with this substrate. Instead, it is consumed in alternative reactions such as disintegration into isobutene, carbon monoxide, and water (retro-Koch reaction). In addition, the carboxylic acid is isomerized or loses carbon atoms, which converts the tertiary carboxylic acid into carboxylic acids bearing α-proton atoms. Hence, the latter are suitable to react through the β-keto acid pathway. A second substrate, 2,2,5,5-tetramethyladipic acid, reacted by following the same retro-Koch pathway. The primary product was the monocarboxylic acid 2,2,5-trimethyl-4-hexenoic acid (and its double bond isomer), which might be further transformed into a cyclic enone or a lactone. The ketonic decarboxylation product, 2,2,5,5-tetramethylcyclopentanone was observed in traces (<0.2 % yield). Therefore, it can be concluded that the observed experimental results further support the proposed mechanism for the ketonic decarboxylation via the β-keto acid intermediate. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. N-heterocyclic carboxylic acids

    Indian Academy of Sciences (India)

    Administrator

    2,3-dicarboxylic acid) is solved by single crystal X-ray diffraction technique. Antibacterial activities of the complexes are evaluated by determining their capacity to inhibit the growth of E. coli 10536 (MIC) in a nutrient broth. Proc. Indian Acad. Sci. (Chem. Sci.), Vol. 112, No. 3, June 2000, p. 355. © Indian Academy of Sciences.

  9. Metal extraction by amides of carboxylic acids

    International Nuclear Information System (INIS)

    Skorovarov, D.I.; Chumakova, G.M.; Rusin, L.I.; Ul'anov, V.S.; Sviridova, R.A.; Sviridov, A.L.

    1988-01-01

    Extraction ability of various amides was studied. Data on extraction of rare earths, vanadium, molybdenum, rhenium, uranium, niobium, tantalum by N,N-dibutyl-amides of acetic, nonanic acids and fatly synthetic acids of C 7 -C 9 fractions are presented. Effect of salting-out agents, inorganic acid concentrations on extraction process was studied. Potential ability of using amides of carboxylic acids for extractional concentration of rare earths as well as for recovery and separation of iron, rhenium, vanadium, molybdenum, uranium, niobium, and tantalum was shown

  10. Production of carboxylic acid and salt co-products

    Science.gov (United States)

    Hanchar, Robert J.; Kleff, Susanne; Guettler, Michael V.

    2014-09-09

    This invention provide processes for producing carboxylic acid product, along with useful salts. The carboxylic acid product that is produced according to this invention is preferably a C.sub.2-C.sub.12 carboxylic acid. Among the salts produced in the process of the invention are ammonium salts.

  11. Applications of Carboxylic Acid Reductases in Oleaginous Microbes

    Energy Technology Data Exchange (ETDEWEB)

    Resch, Michael G.; Linger, Jeffrey; McGeehan, John; Tyo, Keith; Beckham, Gregg

    2016-05-26

    Carboxylic acid reductases (CARs) are recently emerging reductive enzymes for the direct production of aldehydes from biologically-produced carboxylic acids. Recent work has demonstrated that these powerful enzymes are able to reduce a very broad range of volatile- to long-chain fatty acids as well as aromatic acids. Here, we express four CAR enzymes from different fungal origins to test their activity against fatty acids commonly produced in oleaginous microbes. These in vitro results will inform metabolic engineering strategies to conduct mild biological reduction of carboxylic acids in situ, which is conventionally done via hydrotreating catalysis at high temperatures and hydrogen pressures.

  12. Decarboxylative Fluorination of Aliphatic Carboxylic Acids via Photoredox Catalysis

    Science.gov (United States)

    Ventre, Sandrine; Petronijevic, Filip R.; MacMillan, David W. C.

    2016-01-01

    The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F• transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol. PMID:25881929

  13. Cationic mononuclear ruthenium carboxylates as catalyst prototypes for self-induced hydrogenation of carboxylic acids

    Science.gov (United States)

    Naruto, Masayuki; Saito, Susumu

    2015-01-01

    Carboxylic acids are ubiquitous in bio-renewable and petrochemical sources of carbon. Hydrogenation of carboxylic acids to yield alcohols produces water as the only byproduct, and thus represents a possible next generation, sustainable method for the production of these alternative energy carriers/platform chemicals on a large scale. Reported herein are molecular insights into cationic mononuclear ruthenium carboxylates ([Ru(OCOR)]+) as prototypical catalysts for the hydrogenation of carboxylic acids. The substrate-derived coordinated carboxylate was found to function initially as a proton acceptor for the heterolytic cleavage of dihydrogen, and subsequently also as an acceptor for the hydride from [Ru–H]+, which was generated in the first step (self-induced catalysis). The hydrogenation proceeded selectively and at high levels of functional group tolerance, a feature that is challenging to achieve with existing heterogeneous/homogeneous catalyst systems. These fundamental insights are expected to significantly benefit the future development of metal carboxylate-catalysed hydrogenation processes of bio-renewable resources. PMID:26314266

  14. Biodegradation of cycloalkane carboxylic acids in oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D.C.; Costerton, J.W. (Calgary Univ., Dept. of Biological Sciences, AB (Canada)); Fedorak, P.M. (Alberta Univ., Dept. of Microbiology, AB (Canada))

    1993-01-01

    The biodegradation of both an n-alkane and several carboxylated cycloalkanes was examined experimentally within tailings produced by the extraction of bitumen from the Athabasca oil sands. The carboxylated cycloalkanes examined were structurally similar to naphthenic acids that have been associated with the acute toxicity of oil sand tailings. The biodegradation potential of naphthenic acids was estimated by determining the biodegradation of both the carboxylated cycloalkanes and hexadecane in oil sand tailings. Carboxylated cycloalkanes were biodegraded within oil sands tailings, although compounds with methyl substitutions on the cycloalkane ring were more resistant to microbial degradation. Microbial activity against hexadecane and certain carboxylated cycloalkanes was found to be nitrogen and phosphorus limited. 21 refs., 3 refs., 1 tab.

  15. Correction: Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones.

    Science.gov (United States)

    Yin, Feng; Garifullina, Ainash; Tanaka, Fujie

    2018-04-25

    Correction for 'Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones' by Feng Yin et al., Org. Biomol. Chem., 2017, 15, 6089-6092.

  16. Direct esterification of ammonium salts of carboxylic acids

    Science.gov (United States)

    Halpern, Yuval [Skokie, IL

    2003-06-24

    A non-catalytic process for producing esters, the process comprising reacting an ammonium salt of a carboxylic acid with an alcohol and removing ammonia from the reaction mixture. Selectivities for the desired ester product can exceed 95 percent.

  17. Cloning of phenazine carboxylic acid genes of Fusarium fujikuroi ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-08

    PCA), which is active against a variety of fungal root pathogens. ... The antibiotics phenazine-1- carboxylic acid (PCA) and 2 .... presence of genes involved in the biosynthesis of phenazine-derivatives described in P.

  18. Model for the origin of carboxylic acids in basinal brines

    Science.gov (United States)

    Seewald, Jeffrey S.

    2001-11-01

    Carboxylic acids are ubiquitous in basinal brines from petroleum-producing sedimentary basins. Although the absolute concentrations of individual short-chain acids vary systematically over many orders of magnitude, relative abundances are characterized by approximately constant ratios. Laboratory experiments have demonstrated that oxidation of aqueous n-alkanes proceeds through a sequence of reactions involving alkene, alcohol, ketone, and carboxylic acid reaction intermediaries. The highly specific nature of these reactions allows the relative distribution of carboxylic acids produced during oxidation of n-alkanes to be predicted quantitatively as a function of petroleum composition. A model based on the results of laboratory experiments was developed to account for the thermogenic production of aqueous carboxylic acids in sedimentary basins. Model predictions are highly consistent with the distribution of carboxylic acids observed in nature. This result suggests that hydrocarbon oxidation reactions may be pervasive during petroleum maturation in sedimentary basins. Likely oxidizing agents include ferric iron-bearing aluminosilicates, oxides, and hydroxides, pyrite, sulfate-bearing minerals, and water. Such chemical interactions allow inorganic sedimentary components to act as sources of oxygen for the formation of oxygenated organic alteration products. Accordingly, the absolute amount and timing of carboxylic acid generation may not be limited by the compositional evolution of kerogen, as suggested by previous models.

  19. Mechanistic Investigation into the Decarboxylation of Aromatic Carboxylic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Britt, P F; Buchanan, III, A C; Eskay, T P; Mungall, W S

    1999-08-22

    It has been proposed that carboxylic acids and carboxylates are major contributors to cross-linking reactions in low-rank coals and inhibit its thermochemical processing. Therefore, the thermolysis of aromatic carboxylic acids was investigated to determine the mechanisms of decarboxylation at temperatures relevant to coal processing, and to determine if decarboxylation leads to cross-linking (i.e., formation of more refractory products). From the thcrmolysis of simple and polymeric coal model compounds containing aromatic carboxylic acids at 250-425 °C, decarboxylation was found to occur primarily by an acid promoted ionic pathway. Carboxylate salts were found to enhance the decarboxylation rate, which is consistent with the proposed cationic mechanism. Thermolysis of the acid in an aromatic solvent, such as naphthalene, produced a small amount of arylated products (~5 mol%)), which constitute a low-temperature cross-link. These arylated products were formed by the rapid decomposition of aromatic anhydrides, which are in equilibrium with the acid. These anhydrides decompose by a free radical induced decomposition pathway to form atyl radicals that can add to aromatic rings to form cross-links or abstract hydrogen. Large amounts of CO were formed in the thennolysis of the anhydrides which is consistent with the induced decomposition pathway. CO was also formed in the thermolysis of the carboxylic acids in aromatic solvents which is consistent with the formation and decomposition of the anhydride. The formation of anhydride linkages and cross-links was found to be very sensitive to the reactions conditions. Hydrogen donor solvents, such as tetralin, and water were found to decrease the formation of arylated products. Silar reaction pathways were also found in the thermolysis of a polymeric model that contained aromatic carboxylic acids. In this case, anhydride formation and decomposition produced an insoluble polymer, while the O-methylated polymer and the non-carboxylated

  20. Transition Metal Catalyzed Synthesis of Carboxylic Acids, Imines, and Biaryls

    DEFF Research Database (Denmark)

    Santilli, Carola; Madsen, Robert

    Dehydrogenative synthesis of carboxylic acids catalyzed by a ruthenium N- heterocycliccarbene complex. A new methodology for the synthesis of carboxylic acids from primary alcohols and hydroxide has been developed. The reaction is catalyzed by the ruthenium N-heterocycliccarbene complex [RuCl2(Ii...... to the carboxylic acids can be explained by the involvement of a competing Cannizzaro reaction. The scope of the dehydrogenation was further extended to linear and branched saturated aliphatic alcohols, although longer reaction times are necessary to ensure complete substrate conversions. The kinetic isotope effect...... the carboxylate.  Manganese catalyzed radical Kumada-type reaction between aryl halidesand aryl Grignard reagents. The reaction between aryl halides and aryl Grignard reagents catalyzed by MnCl2 has been extended to several methyl-substituted aryl iodide reagents byperforming the reaction at 120 ˚C in a microwave...

  1. Separation of certain carboxylic acids utilizing cation exchange membranes

    Science.gov (United States)

    Chum, Helena L.; Sopher, David W.

    1984-01-01

    A method of substantially separating monofunctional lower carboxylic acids from a liquid mixture containing the acids wherein the pH of the mixture is adjusted to a value in the range of from about 1 to about 5 to form protonated acids. The mixture is heated to an elevated temperature not greater than about 100.degree. C. and brought in contact with one side of a perfluorinated cation exchange membrane having sulfonate or carboxylate groups or mixtures thereof with the mixture containing the protonated acids. A pressure gradient can be established across the membrane with the mixture being under higher pressure, so that protonated monofunctional lower carboxylic acids pass through the membrane at a substantially faster rate than the remainder of the mixture thereby substantially separating the acids from the mixture.

  2. Pd(II)/Bipyridine-Catalyzed Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Carboxylic Acids. Synthesis of β-Quaternary Carbons Substituted Carboxylic Acids.

    Science.gov (United States)

    Liu, Rui; Yang, Zhenyu; Ni, Yuxin; Song, Kaixuan; Shen, Kai; Lin, Shaohui; Pan, Qinmin

    2017-08-04

    Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.

  3. CARBOXYLIC ACIDS OF HERB OF THYMUS CRETACEUS KLOK. ET SCHOST

    Directory of Open Access Journals (Sweden)

    V. N. Bubenchikova

    2014-01-01

    Full Text Available We have studied carboxylic acids of the herb of Thymus cretaceus Klok. et Schost which is widespread on a territory of some regions (Belgorod, Voronezh. The study was carried out using gas-liquid chromatography at Agilent Technologies 6890 chromatographer with massspectrometric detector 5973 N. Acids concentration was calculated by means of inner standard.We have established that carboxylic acids of Thymus cretaceus are represented by 34 compounds. Palmitic (1779.02 mg/kg, behenic (1084.15 mg/kg, levulinic (986.24 mg/kg and linoleic acids (678.82 mg/kg predominate among fatty acids; citric (9835.14 mg/kg, malonic (447.91 mg/kg and oxalic acids (388.32 mg/kg predominate among organic acids; andferulic acid predominate amongphenolcarbonic acids.

  4. Hydrogenation of carboxylic acids with a homogeneous cobalt catalyst.

    Science.gov (United States)

    Korstanje, Ties J; van der Vlugt, Jarl Ivar; Elsevier, Cornelis J; de Bruin, Bas

    2015-10-16

    The reduction of esters and carboxylic acids to alcohols is a highly relevant conversion for the pharmaceutical and fine-chemical industries and for biomass conversion. It is commonly performed using stoichiometric reagents, and the catalytic hydrogenation of the acids previously required precious metals. Here we report the homogeneously catalyzed hydrogenation of carboxylic acids to alcohols using earth-abundant cobalt. This system, which pairs Co(BF4)2·6H2O with a tridentate phosphine ligand, can reduce a wide range of esters and carboxylic acids under relatively mild conditions (100°C, 80 bar H2) and reaches turnover numbers of up to 8000. Copyright © 2015, American Association for the Advancement of Science.

  5. Dimerization of Carboxylic Acids: An Equation of State Approach

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Panayiotou, Costas

    2017-01-01

    The association term of the nonrandom hydrogen bonding theory, which is an equation of state model, is extended to describe the dimerization of carboxylic acids in binary mixtures with inert solvents and in systems of two different acids. Subsequently, the model is applied to describe the excess....... Consequently, the observed endothermic dissolution process is mainly attributed to the hindering of polar interactions. Furthermore, upon mixing of two carboxylic acids, the rearrangement of hydrogen bonds due to the formation of cross associating species results in an insignificant contribution to the heats...

  6. Carboxylic acid terminated, solution exfoliated graphite by organic ...

    Indian Academy of Sciences (India)

    under mild conditions using succinic anhydride as acylating agent and anhydrous aluminum chloride as Lewis acid. Such reaction renders towards the carboxylic acid terminated graphite nanosheets (SEGn–FC) that usually requires harsh reaction conditions. The product thus obtained was characterized using various ...

  7. Novel Lactate Transporters from Carboxylic Acid-Producing Rhizopus

    Science.gov (United States)

    The fungus Rhizopus is frequently used for fermentative production of lactic acid, but little is known about the mechanisms or proteins for transporting this carboxylic acid. Since transport of the lactate anion across the plasma membrane is critical to prevent acidification of the cytoplasm, we ev...

  8. Hydroxy, carboxylic and amino acid functionalized ...

    Indian Academy of Sciences (India)

    precipitation method and modified with different coating agents such as ascorbic acid, hexanoic acid, salicylic acid, L-arginine and L-cysteine. The synthesized nanoparticles were characterized by various techniques such as FT IR, XRD, VSM, ...

  9. Novel Polymers with a High Carboxylic Acid Loading

    DEFF Research Database (Denmark)

    Thomsen, Anders Daugaard; Malmström, Eva; Hvilsted, Søren

    2006-01-01

    ABSTRACT: Click chemistry has been used to prepare a range of novel polymers with pendant carboxylic acid side groups. Four azido carboxylic acids, either mono- or difunctional and aliphatic or aromatic, have been prepared and thoroughly characterized. Extensive model reactions with 1-ethyl-4......-hydroxybenzene, the simplest model for poly(4-hydroxystyrene), and the four azido carboxylic acids have been conucted to establish the proper reaction conditions and provide an analytical frame for the corresponding polymers. Poly(4-hydroxystyrene) moieties in three different polymers—poly (4-hydroxystyrene...... investigations of ali the polymers in general exhibit [when poly(4-hydroxystyrene) is a subetantial parti significant changes in the glass-transition temperature from the polar poly(4-hydroxystyr- ene) (120—130 “C) to the much less polar alkyne polymers (46—60 DC). A direct correlation between the nature...

  10. Aliphatic carboxylic acids and ketones from sapropelitic coals

    Energy Technology Data Exchange (ETDEWEB)

    Bodoev, N.V.; Rokosov, Y.V.; Koptyug, V.A. (USSR Academy of Sciences, Kemerovo (USSR). Institute of Coal)

    1990-02-01

    Normal aliphatic carboxylic acids and ketones obtained from the extraction of Taimylyr (Lensky basin, USSR) or Matagan (Irkutsky basin, USSR) sapropelitic coal with water and sodium hydroxide at elevated pressure and temperatures from 400 to 450{degree}C were investigated. The compositions of these compounds were studied by i.r. and n.m.r. spectroscopy, and combined g.c.-m.s.. The possible pathways of aliphatic carboxylic acids and ketones formation during the fossilization process are discussed. 9 refs., 6 figs., 1 tab.

  11. Synthesis and characterization of carboxylic acid functionalized silicon nanoparticles

    Science.gov (United States)

    Shaner, Ted V.

    Silicon nanoparticles are of great interest in a great number of fields. Silicon nanoparticles show great promise particularly in the field of bioimaging. Carboxylic acid functionalized silicon nanoparticles have the ability to covalently bond to biomolecules through the conjugation of the carboxylic acid to an amine functionalized biomolecule. This thesis explores the synthesis of silicon nanoparticles functionalized by both carboxylic acids and alkenes and their carboxylic acid functionality. Also discussed is the characterization of the silicon nanoparticles by the use of x-ray spectroscopy. Finally, the nature of the Si-H bond that is observed on the surface of the silicon nanoparticles will be investigated using photoassisted exciton mediated hydrosilation reactions. The silicon nanoparticles are synthesized from both carboxylic acids and alkenes. However, the lack of solubility of diacids is a significant barrier to carboxylic acid functionalization by a mixture of monoacids and diacids. A synthesis route to overcome this obstacle is to synthesize silicon nanoparticles with terminal vinyl group. This terminal vinyl group is distal to the surface of the silicon nanoparticle. The conversion of the vinyl group to a carboxylic acid is accomplished by oxidative cleavage using ozonolysis. The carboxylic acid functionalized silicon nanoparticles were then successfully conjugated to amine functionalized DNA strand through an n-hydroxy succinimide ester activation step, which promotes the formation of the amide bond. Conjugation was characterized by TEM and polyacrylamide gel electrophoresis (PAGE). The PAGE results show that the silicon nanoparticle conjugates move slower through the polyacrylamide gel, resulting in a significant separation from the nonconjugated DNA. The silicon nanoparticles were then characterized by the use of x-ray absorption near edge spectroscopy (Xanes) and x-ray photoelectron spectroscopy (XPS) to investigate the bonding and chemical

  12. Hydroxy, carboxylic and amino acid functionalized ...

    Indian Academy of Sciences (India)

    Abstract. Superparamagnetic iron oxide nanoparticles were synthesized by simple co-precipitation method and modified with different coating agents such as ascorbic acid, hexanoic acid, salicylic acid, L-arginine and L-cysteine. The synthesized nanoparticles were characterized by various techniques such as FT IR, XRD,.

  13. Determination of carboxyl groups in humic acids by FTIR spectrophotometry

    Czech Academy of Sciences Publication Activity Database

    Novák, František; Machovič, V.; Poledna, J.

    2005-01-01

    Roč. 1, č. 1 (2005), s. 141 ISSN 1336-7242. [Zjazd chemických spoločností /57./. 04.09.2005-08.09.2005, Tatranské Matliare] Institutional research plan: CEZ:AV0Z60660521 Keywords : carboxyl groups * humic acids * FTIR spectrophotometry Subject RIV: EH - Ecology, Behaviour

  14. Sodium borohydride reduction of aromatic carboxylic acids via ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride–THF–methanol system. The alcohols are obtained in 70–92% yields in 2–. 5 hours, in ...

  15. Modification of polysulfone with pendant carboxylic acid functionality ...

    Indian Academy of Sciences (India)

    271–276. c Indian Academy of Sciences. Modification of polysulfone with pendant carboxylic acid functionality for ultrafiltration membrane applications. ANNADANAM V SESHA SAINATH†,∗ and A V R REDDY. ∗. Reverse Osmosis Division, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar 364 002, ...

  16. Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

    African Journals Online (AJOL)

    NICO

    Atmospheric aerosol samples of PM2.5 and PM10 were collected in April–May 2011 from a rural site in Tanzania and analyzed for water-soluble inorganic ions and low molecular weight carboxylic acids using ion chromatography. PM2.5 and PM10 low-volume samplers with quartz fibre filters were deployed and aerosol ...

  17. Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

    African Journals Online (AJOL)

    Oxalate and malonate inPM2.5 and acetate in PM10 were most abundant carboxylates accounting for 64% and 62 % of total acids, respectively. Mg2+ was most important cation in PM2.5 and PM10 accounting for 44 % and 24 % of total water-soluble ions, respectively, whereas SO4 2- was the main anionic component ...

  18. Dimerization of Carboxylic Acids: An Equation of State Approach

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Panayiotou, Costas

    2017-01-01

    . Consequently, the observed endothermic dissolution process is mainly attributed to the hindering of polar interactions. Furthermore, upon mixing of two carboxylic acids, the rearrangement of hydrogen bonds due to the formation of cross associating species results in an insignificant contribution to the heats...... enthalpies and the vapor-liquid equilibrium of relevant binary mixtures containing low molecular weight organic acids. The model sheds light on the interplay of intermolecular interactions through the calculation of the various contributions to the mixing enthalpies, namely from hydrogen bonding and non......-hydrogen bonding (dipolar, induced polar or dispersive) interactions. According to model predictions, the acid molecules are so strongly associated that the addition of inert solvents to carboxylic acids with small carbon numbers at ambient temperature does not dramatically alter their degree of association...

  19. Monte carlo simulation of carboxylic acid phase equilibria.

    Science.gov (United States)

    Clifford, Scott; Bolton, Kim; Ramjugernath, Deresh

    2006-11-02

    Configurational-bias Monte Carlo simulations were carried out in the Gibbs ensemble to generate phase equilibrium data for several carboxylic acids. Pure component coexistence densities and saturated vapor pressures were determined for acetic acid, propanoic acid, 2-methylpropanoic acid, and pentanoic acid, and binary vapor-liquid equilibrium (VLE) data for the propanoic acid + pentanoic acid and 2-methylpropanoic acid + pentanoic acid systems. The TraPPE-UA force field was used, as it has recently been extended to include parameters for carboxylic acids. To simulate the branched compound 2-methylpropanoic acid, certain minor assumptions were necessary regarding angle and torsion terms involving the -CH- pseudo-atom, since parameters for these terms do not exist in the TraPPE-UA force field. The pure component data showed good agreement with the available experimental data, particularly with regard to the saturated liquid densities (mean absolute errors were less than 1.1%). On average, the predicted critical temperature and density were within 1% of the experimental values. All of the binary simulations showed good agreement with the experimental x-y data. However, the TraPPE-UA force field predicts saturated vapor pressures of pure components that are larger than the experimental values, and consequently the P-x-y and T-x-y data of the binary systems also deviate from the measured data.

  20. Hydroxy, carboxylic and amino acid functionalized ...

    Indian Academy of Sciences (India)

    In vitro cytotoxicity test of bare and coated nanoparticles was performed using adenocarcinoma cells, A549. Cell viability ... Keywords. Magnetite nanoparticles; acid-coated magnetite nanoparticles; cytotoxicity; DNA fragmentation. 1. Introduction ...... terfaces 82 160. 6. Gupta A K and Gupta M 2005 Biomaterials 26 1565. 7.

  1. Separation and determination of some carboxylic acids by capillary electrophoresis

    International Nuclear Information System (INIS)

    Sladkov, V.; Fourest, B.

    2006-01-01

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  2. Separation and determination of some carboxylic acids by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Sladkov, V.; Fourest, B

    2006-07-01

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  3. Extraction of scandium by aromatic carboxylic acids

    International Nuclear Information System (INIS)

    Kamenev, V.F.; Fadeeva, V.I.

    1977-01-01

    Extraction of complex compounds af scandium with salicylic, phenyl- and diphenylacetic acids with chloroform solutions of tetraethyldiamideheptylphosphate as a donor-active additive in relation to the pH and reagent concentration has been studied. Extraction of salicylates of some elements (Ta, Nb, Zr, Hf, Mo) by solutions of tetraethyldiamideheptylphosphate in chloroform has been investigated, and the possibility of their extraction separation from scandium is shown

  4. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    DEFF Research Database (Denmark)

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested a...

  5. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated carboxylic acid alkali... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under this...

  6. Carboxylic acid-functionalized SBA-15 nanorods for gemcitabine delivery

    International Nuclear Information System (INIS)

    Bahrami, Zohreh; Badiei, Alireza; Ziarani, Ghodsi Mohammadi

    2015-01-01

    The present study deals with the functionalization of mesoporous silica nanoparticles as drug delivery systems. Mono, di, and tri amino-functionalized SBA-15 nanorods were synthesized by post-grafting method using (3-aminopropyl) triethoxysilane, N-(2-aminoethyl-)3- aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino) ethylamino] propyl trimethoxysilane, respectively. The carboxylic acid derivatives of the amino-functionalized samples were obtained using succinic anhydride. Tminopropyltrimethoxysilanehe obtained modified materials were investigated as matrixes for the anticancer drug (gemcitabine) delivery. The prepared samples were characterized by SAXS, N 2 adsorption/desorption, SEM, transmission electron microscopy, thermogravimetric analysis, and FTIR and UV spectroscopies. The adsorption and release properties of all samples were studied. It was revealed that the adsorption capacity and release behavior of gemcitabine were highly dependent on the type of the introduced functional groups. The carboxylic acid-modified samples have higher loading content, due to the strong interaction with gemcitabine. The maximum content of deposited drug in the modified SBA-15 nanorods is close to 40 wt%. It was found that the surface functionalization leads toward significant decrease of the drug release rate. The carboxylic acid-functionalized samples have slower release rate in contrast with the amino-functionalized samples

  7. Extraction characteristics of trivalent lanthanides and actinides in mixtures of dinonylnaphthalenesulfonic acid and carboxylic acids

    International Nuclear Information System (INIS)

    West, M.H.

    1983-03-01

    Dinonylnaphthalenesulfonic acid (HDNNS) has been shown to be an effective liquid cation exchanger for the extraction of metal ions. This extractant has proven to be successful in the extraction of trivalent lanthanides and actinides in the pH range of 2.0 to 3.0, although it shows little selectivity for individual ions because of its strong acid character. In an effort to improve the selectivity of HDNNS between trivalent lanthanides and actinides, carboxylic acids were added to the organic phase and the effects on the extraction characteristics of HDNNS were investigated. Three carboxylic acids - nonanoic, cyclohexanecarboxylic, and cyclohexanebutyric - were studied with the following metals: Am(III), Cm(III), Ce(III), Eu(III), and Tm(III). The distributions of the metal ions were studied holding the HDNNS concentration constant while varying the carboxylic acid concentrations over a range of 1.0 x 10 -5 M to 1.0 M. Results indicated that the greatest enhancement of the extraction occurred at a carboxylic acid concentration of 1.0 x 10 -2 M with negative effects occurring at 0.5 M and 1.0 M. The effects on the extraction of the trivalent lanthanides and actinides were interpreted in terms of the structural differences of the carboxylic acids, the effect of the carboxylic acids on the HDNNS extraction mechanism, and the ionic properties of the metals studied

  8. Development of starch biofilms using different carboxylic acids as plasticizers

    International Nuclear Information System (INIS)

    Cruz, L.C.; Miranda, C.S.; Santos, W.J. dos; Goncalves, A.P.B.; Oliveira, J.C.; Jose, N.M.

    2014-01-01

    Biodegradable films have become a widely exploited issue among scientists because of their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life. Starch has been studied in this field due to its availability, low cost and biodegradability. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids chain size in the final films properties. The acids used were: oxalic, succinic and adipic. The materials were produced by casting and characterized by DSC, TG, DRX e FTIR. It was observed that the acids chain size influenced on the thermal and structural properties of the films. (author)

  9. Catalysis of the Carbonylation of Alcohols to Carboxylic Acids Including Acetic Acid Synthesis from Methanol.

    Science.gov (United States)

    Forster, Denis; DeKleva, Thomas W.

    1986-01-01

    Monsanto's highly successful synthesis of acetic acid from methanol and carbon monoxide illustrates use of new starting materials to replace pretroleum-derived ethylene. Outlines the fundamental aspects of the acetic acid process and suggests ways of extending the synthesis to higher carboxylic acids. (JN)

  10. Formation of biologically relevant carboxylic acids during the gamma irradiation of acetic acid

    Science.gov (United States)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1976-01-01

    Irradiation of aqueous solutions of acetic acid with gamma rays produced several carboxylic acids in small yield. Their identification was based on the technique of gas chromatography combined with mass spectrometry. Some of these acids are Krebs Cycle intermediates. Their simultaneous formation in experiments simulating the primitive conditions on the earth suggests that metabolic pathways may have had their origin in prebiotic chemical processes.

  11. Prebiotic synthesis of carboxylic acids, amino acids and nucleic acid bases from formamide under photochemical conditions⋆

    Science.gov (United States)

    Botta, Lorenzo; Mattia Bizzarri, Bruno; Piccinino, Davide; Fornaro, Teresa; Robert Brucato, John; Saladino, Raffaele

    2017-07-01

    The photochemical transformation of formamide in the presence of a mixture of TiO2 and ZnO metal oxides as catalysts afforded a large panel of molecules of biological relevance, including carboxylic acids, amino acids and nucleic acid bases. The reaction was less effective when performed in the presence of only one mineral, highlighting the role of synergic effects between the photoactive catalysts. Taken together, these results suggest that the synthesis of chemical precursors for both the genetic and the metabolic apparatuses might have occurred in a simple environment, consisting of formamide, photoactive metal oxides and UV-radiation.

  12. (Quinoline-2-carboxylato-κO)(quinoline-2-carboxylic acid-κO)bis(quinoline-2-carboxylic acid-κ2N,O)potassium

    OpenAIRE

    Seik Weng Ng

    2010-01-01

    The K atom in the title complex, [K(C10H6NO2)(C10H7NO2)3], lies on a twofold rotation axis that relates one N,O-chelating quinoline-2-carboxylic acid to the other; their N and O atoms are cis to each other in the distorted octahedral coordination geometry. The K atom is also coordinated by another monodentate quinoline-2-carboxylic acid; the acid is disordered with respect to a monodentate quinoline-2-carboxylate anion; the acid and anion are linked by an O—H...O hydrogen bond. An O...

  13. Carboxylic acids in high elevation Alpine glacier snow

    Science.gov (United States)

    Maupetit, FrançOis; Delmas, Robert J.

    1994-08-01

    Fresh-snow samples were collected on an event basis on the Glacier de la Girose (3360 m above sea level (asl)) in the southern French Alps, during winters and early springs 1990 and 1991. In addition, a 13-m firn core was recovered in 1991 at the Col du Dôme (4250 m asl), a cold glacier in the northern French Alps, offering the complete seasonal record of alpine precipitation during 3.5 years. All samples were analyzed for total formate and acetate and for major ions using ion chromatography. The acidity-alkalinity was accurately measured using a titration technique. An almost perfect ion balance was achieved for this data set. In absence of Saharan dust transport, the high alpine snow is slightly acid (H+ ˜ 2-20 μEq L-1). HCOOT and CH3COOT are generally present in alpine acid snow at very low concentrations: 0.3-0.6 μEq L-1 in winter (January to February) and 0.6-2 μEq L-1 in early spring (March to April). At Col du Dôme, total acetate concentrations of ˜1 μEq L-1 are observed in summer. It remains unclear from our results what the major sources of carboxylic acids are, and in particular of acetic acid, in the wintertime continental free troposphere, while it appears that formic and acetic acids are presumably mainly derived from natural sources in spring and summer. The total contribution of formic and acetic acids to free acidity is, on average, less than 15-20%. Contrary to major ions which are present in wider concentration ranges and show large variations from one snowfall to the other, HCOOT and CH3COOT are surprisingly stable in acid alpine snow. The only significant deviation of HCOOT and CH3COOT from their mean values (up to 9 and 5 μEq L-1, respectively) are observed in case of Saharan dust transport, when precipitation pH is shifted from acid toward alkaline conditions. These observations suggest a pH partitioning effect between the aqueous and gas phases, formic and acetic acids being dissolved and neutralized as salts in alkaline cloudwater

  14. SYNTHESIS OF FLAVANONE-6-CARBOXYLIC ACID DERIVATIVES FROM SALICYLIC ACID DERIVATIVE

    OpenAIRE

    Mardjan, Muhammad Idham Darussalam; Ambarwati, Retno; Matsjeh, Sabirin; Wahyuningsih, Tutik Dwi; Haryadi, Winarto

    2012-01-01

    Synthesis of flavanone-6-carboxylic acid derivatives had been conducted via the route of chalcone. The synthesis was carried out from salicylic acid derivative, i.e. 4-hydroxybenzoic acid, via esterification, Fries rearrangement, Claisen-Schmidt condensation and 1,4-nucleophilic addition reactions. Structure elucidation of products was performed using FT-IR, 1H-NMR, GC-MS and UV-Vis spectrometers. Reaction of 4-hydroxybenzoic acid with methanol catalyzed with sulfuric acid produced methyl 4-h...

  15. In situ Recovery of Bio-Based Carboxylic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Eric M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saboe, Patrick [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Manker, Lorenz [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Michener, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Peterson, Darren J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brandner, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Deutch, Stephen P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cywar, Robin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kumar, Manish [Pennsylvania State University

    2018-03-16

    The economics of chemical and biological processes is often dominated by the expense of downstream product separations from dilute product streams. Continuous separation techniques, such as in situ product recovery (ISPR), are attractive in that they can concentrate products from a reactor and minimize solvent loss, thereby increasing purity and sustainability of the process. In bioprocesses, ISPR can have an additional advantage of increasing productivity by alleviating product inhibition on the microorganism. In this work, we developed a liquid-liquid extraction (LLE)-based ISPR system integrated with downstream distillation to selectively purify free carboxylic acids, which were selected as exemplary bioproducts due to their ability to be produced at industrially relevant titers and productivities. Equilibrium constants for the extraction of carboxylic acids into a phosphine-oxide based organic phase were experimentally determined. Complete recovery of acids from the extractant and recyclability of the organic phase were demonstrated through multiple extraction-distillation cycles. Using these data, an equilibrium model was developed to predict the acid loading in the organic phase as a function of the extraction equilibrium constant, initial aqueous acid concentration, pH, organic to aqueous volume ratio, and temperature. A distillation process model was then used to predict the energy input required to distill neat acid from an organic phase as a function of the acid loading in the organic phase feed. The heat integrated distillation train can achieve neat recovery of acetic acid with an energy input of 2.6 MJ kg-1 of acetic acid. This LLE-based ISPR system integrated with downstream distillation has an estimated carbon footprint of less than 0.36 kg CO2 per kg of acetic acid, and provides a green approach to enable both new industrial bioprocesses, and process intensification of existing industrial operations by (1) increasing the productivity and titer of

  16. Azetidine-2-carboxylic acid in the food chain.

    Science.gov (United States)

    Rubenstein, Edward; McLaughlin, Theresa; Winant, Richard C; Sanchez, Agustin; Eckart, Michael; Krasinska, Karolina M; Chien, Allis

    2009-01-01

    Azetidine-2-carboxylic acid (Aze) 1 is a non-protein amino acid present in sugar beets and in table beets (Beta vulgaris). It is readily misincorporated into proteins in place of proline 2 in many species, including humans, and causes numerous toxic effects as well as congenital malformations. Its role in the pathogenesis of disease in humans has remained unexplored. Sugar beet agriculture, especially in the Northern Hemisphere, has become widespread during the past 150 years, and now accounts for nearly 30% of the world's supply of sucrose. Sugar beet byproducts are also used as a dietary supplement for livestock. Therefore, this study was undertaken as an initial survey to identify Aze-containing links in the food chain. Herein, we report the presence of Aze 1 in three sugar beet byproducts that are fed to farm animals: sugar beet molasses, shredded sugar beet pulp, and pelleted sugar beet pulp.

  17. Dielectric properties of supramolecular ionic structures obtained from multifunctional carboxylic acids and amines

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Yu, Liyun; Hvilsted, Søren

    2014-01-01

    networks, formed by mixing multifunctional carboxylic acids such as citric acid (CA), tricarballylic acid (TCAA), trimesic acid (TMA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DETPA) with two di ff erent Je ff amine polyetheramines (designated as D400 and D2000......), are investigated. Here the relative dielectric permittivities of the supramolecular ionic structures formed with the multifunctional carboxylic acids were lower than those from the supramolecular ionic structures formed with the two carboxymethyl ether-terminated poly(ethylene glycol)s....

  18. The acid-base character of interactions between xenon and selected carboxylic and sulfonic acids

    Science.gov (United States)

    Gąszowski, Dawid; Ilczyszyn, Marek

    2017-05-01

    Interactions of Xe atoms with RCO2H and RSO3H (R = CH3 and CF3) acids in different solvents are examined by analysis of 129Xe chemical shifts extrapolated to zero solvent concentration. Obtained results are very sensitive to the Xe contacts with the methyl and trifluoromethyl groups as well as with the carboxylic and sulfonic groups of different acidity. The acid-base character of these acid-Xe interactions is considered.

  19. Aerosol volatility and enthalpy of sublimation of carboxylic acids.

    Science.gov (United States)

    Salo, Kent; Jonsson, Asa M; Andersson, Patrik U; Hallquist, Mattias

    2010-04-08

    The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the previous use of a VTDMA, this novel method gives enthalpy of sublimation determined over an extended temperature range (DeltaT approximately 40 K). The determined enthalpy of sublimation for the straight-chain dicarboxylic acids ranged from 96 to 161 kJ mol(-1), and the calculated vapor pressures at 298 K are in the range of 10(-6)-10(-3) Pa. These values indicate that dicarboxylic acids can take part in gas-to-particle partitioning at ambient conditions and may contribute to atmospheric nucleation, even though homogeneous nucleation is unlikely. To obtain consistent results, some experimental complications in producing nanosized crystalline aerosol particles were addressed. It was demonstrated that pinonic acid "used as received" needed a further purification step before being suspended as a nanoparticle aerosol. Furthermore, it was noted from distinct differences in thermal properties that aerosols generated from pimelic acid solutions gave two types of particles. These two types were attributed to crystalline and amorphous configurations, and based on measured thermal properties, the enthalpy of vaporization was 127 kJ mol(-1) and that of sublimation was 161 kJ mol(-1). This paper describes a new method that is complementary to other similar methods and provides an extension of existing experimental data on physical properties of atmospherically relevant compounds.

  20. 40 CFR 721.2088 - Carboxylic acids, (C6-C9) branched and linear.

    Science.gov (United States)

    2010-07-01

    ... linear. 721.2088 Section 721.2088 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.2088 Carboxylic acids, (C6-C9) branched and linear. (a) Chemical... as carboxylic acids, (C6-C9) branched and linear (PMNs P-93-313, 314, 315, and 316) are subject to...

  1. Synthesis and bioactivities of Phenazine-1-carboxylic acid derivatives based on the modification of PCA carboxyl group.

    Science.gov (United States)

    Xiong, Zhipeng; Niu, Junfan; Liu, Hao; Xu, Zhihong; Li, Junkai; Wu, Qinglai

    2017-05-01

    Phenazine-1-carboxylic acid (PCA) as a natural product widely exists in microbial metabolites of Pseudomonads and Streptomycetes and has been registered for the fungicide against rice sheath blight in China. To find higher fungicidal activities compounds and study the effects on fungicidal activities after changing the carboxyl group of PCA, we synthesized a series of PCA derivatives by modifying the carboxyl group of PCA and their structures were confirmed by 1 H NMR and HRMS. Most compounds exhibited significant fungicidal activities in vitro. In particular, compound 6 exhibited inhibition effect against Rhizoctonia solani with EC 50 values of 4.35mg/L and compound 3b exhibited effect against Fusarium graminearum with EC 50 values of 8.30mg/L, compared to the positive control PCA with its EC 50 values of 7.88mg/L (Rhizoctonia solani) and 127.28mg/L (Fusarium graminearum), respectively. The results indicated that the carboxyl group of PCA could be modified to be amide group, acylhydrazine group, ester group, methyl, hydroxymethyl, chloromethyl and ether group etc. And appropriate modifications on carboxyl group of PCA were useful to extend the fungicidal scope. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. SYNTHESIS OF FLAVANONE-6-CARBOXYLIC ACID DERIVATIVES FROM SALICYLIC ACID DERIVATIVE

    Directory of Open Access Journals (Sweden)

    Muhammad Idham Darussalam Mardjan

    2012-02-01

    Full Text Available Synthesis of flavanone-6-carboxylic acid derivatives had been conducted via the route of chalcone. The synthesis was carried out from salicylic acid derivative, i.e. 4-hydroxybenzoic acid, via esterification, Fries rearrangement, Claisen-Schmidt condensation and 1,4-nucleophilic addition reactions. Structure elucidation of products was performed using FT-IR, 1H-NMR, GC-MS and UV-Vis spectrometers. Reaction of 4-hydroxybenzoic acid with methanol catalyzed with sulfuric acid produced methyl 4-hydroxybenzoate in 87% yield. The acid-catalyzed-acetylation of the product using acetic anhydride gave methyl 4-acetoxybenzoate in 75% yield. Furthermore, solvent-free Fries rearrangement of methyl 4-acetoxybenzoate in the presence of AlCl3 produced 3-acetyl-4-hydroxybenzoic acid as the acetophenone derivatives in 67% yield. Then, Claisen-Schmidt condensation of the acetophenone and benzaldehyde derivatives of p-anisaldehyde and veratraldehyde in basic condition gave 2'-hydroxychalcone-5'-carboxylic acid derivatives  in 81 and 71 % yield, respectively. Finally, the ring closure reaction of the chalcone yielded the corresponding flavanone-6-carboxylic acids in 67 and 59% yield, respectively.

  3. Comparative in vitro toxicity assessment of perfluorinated carboxylic acids.

    Science.gov (United States)

    Mahapatra, Cecon T; Damayanti, Nur P; Guffey, Samuel C; Serafin, Jennifer S; Irudayaraj, Joseph; Sepúlveda, Maria S

    2017-06-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic fluorinated compounds that are highly bioaccumulative and persistent organic pollutants. Perfluorooctanoic acid (PFOA), an eight-carbon chain perfluorinated carboxylic acid, was used heavily for the production of fluoropolymers, but concerns have led to its replacement by shorter carbon chain homologues such as perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA). However, limited toxicity data exist for these substitutes. We evaluated the toxicity of PFOA, PFHxA and PFBA on a zebrafish liver cell line and investigated the effects of exposure on cell metabolism. Gross toxicity after 96 h of exposure was highest for PFOA and PFO - , while PFHxA and PFBA exhibited lower toxicity. Although the structural similarity of these compounds to fatty acids suggests the possibility of interference with the transport and metabolism of lipids, we could not detect any differential expression of peroxisome proliferator-activated receptor (ppar-α, -β and -γ), fabp3 and crot genes after 96 h exposure to up to 10 ppm of the test compounds. However, we observed localized lipid droplet accumulation only in PFBA-exposed cells. To study the effects of these compounds on cell metabolism, we conducted fluorescence lifetime imaging microscopy using naturally fluorescent biomarkers, NADH and FAD. The fluorescence lifetimes of NADH and FAD and the bound/free ratio of each of these coenzymes decreased in a dose- and carbon length-dependent manner, suggesting disruption of cell metabolism. In sum, our study revealed that PFASs with shorter carbon chains are less toxic than PFOA, and that exposure to sublethal dosage of PFOA, PFHxA or PFBA affects cell metabolism. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Enhancement of carboxylic acid degradation with sulfate radical generated by persulfate activation.

    Science.gov (United States)

    Criquet, J; Nebout, P; Karpel Vel Leitner, N

    2010-01-01

    The aim of this work was to investigate the generation of sulfate radical for the removal of two carboxylic acids in aqueous solution: acetic and citric acids. From photochemical and radiolytic processes, kinetics of the degradation of these two carboxylic acids was studied as a function of the pH of the solution. It was shown that the maximum of acetic acid degradation occurred at pH 5. Above this pH, competitive reactions with the carbon mineralized inhibit the reaction of with the solute. In the case of citric acid, pH has only a little effect on the kinetic of citric acid degradation. The determination of mineralization yields shows several differences depending on carboxylic acids and pH. The degradation of both carboxylic acids was also studied in the radiolysis process whether with or without persulfate addition. A comparison of the processes of sulfate radical production is presented.

  5. Structural and thermal properties of carboxylic acid functionalized polythiophenes

    Directory of Open Access Journals (Sweden)

    Ariane de França Mescoloto

    2014-01-01

    Full Text Available Polythiophenes functionalized with polar groups at the end of side-chain have emerged as an alternative method to obtain good compatibility between this class of conjugated polymers and electron acceptor compounds. The aim is to prevent phase segregation and to improve the efficiency of the polythiophene technological devices. However, homopolymers synthesized from thiophene rings with high polar groups at the end of the side-chain, such as hydroxyl and carboxylic acid groups, are poorly soluble in common volatile organic solvents. We report on a systematic preparation of copolymers of 3-hexylthiophene (HT and thiophene-3-acetic acid (TAA, using different feed ratios. The chemical structures of the copolymers were confirmed by FTIR and ¹H-NMR. The TAA content in these copolymers were 33, 38 and 54 mol %. HPSEC results did not show any remarkable correlation with TAA contents in the copolymers. In contrast, the thermal analyses showed a decrease in the thermal stability and an increase in rigidity of their backbones, for the copolymers with high amounts of TAA. The solubility and optical property of copolymers were also related to the TAA contents. Thus, the properties of these copolymers can be modulated by a simple control of feed ratio of TAA in the copolymerization.

  6. Effectiveness of carboxylic acids from Pichia membranifaciens against coffee rust

    Directory of Open Access Journals (Sweden)

    Rosa Laura Andrade Melchor

    Full Text Available ABSTRACT Coffee rust is a fungal disease that has affected every coffee-producing region in the world. Given that the effectivity of the protectant and systemic fungicides applied routinely to control the spread of the causative agent of the disease (Hemileia vastatrix has gradually diminished, besides are harmful to mammals and ecosystems, the objective of this work was to search for a mixture of harmless natural compounds with the potential to be applied in the field. So, a yeast strain producing a battery of long-chain carboxylic acids (CA with fungicide properties was isolated from soil of coffee crop and identified as Pichia membranifaciens by ITS sequencing. Culture conditions of the yeast were optimized and the CA in the solution were characterized by Gas Chromatography-Mass Spectrometry (GC-MS as ethyl formate (55.5 g L-1, octadecenoic acid (3.5 g L-1, propionic acid (7.2 g L-1, 3-(octadecanoyl-propionic acid (7.2 g L-1 and methyl acetate (8.4 g L-1. Randomized field studies were conducted in three different locations in Chiapas, México. Five treatments were tested including three concentrations of the CA solution (389, 584 and 778 ppm and copper oxychloride (5 000 ppm as conventional control. The initial coffee rust incidence averages varied between sites: Maravillas (3-9%, Santo Domingo (10-16% and Búcaro (16-22%. The treatments of CA solution proved to be effective at slowing down the progress of the rust disease even for the sites where initial incidence was high. Likewise, the CA solution reduced the viability of H. vastatrix spores, as assessed by fluorescence microscopy.

  7. Chiral metal-organic frameworks bearing free carboxylic acids for organocatalyst encapsulation.

    Science.gov (United States)

    Liu, Yan; Xi, Xiaobing; Ye, Chengcheng; Gong, Tengfei; Yang, Zhiwei; Cui, Yong

    2014-12-08

    Two chiral carboxylic acid functionalized micro- and mesoporous metal-organic frameworks (MOFs) are constructed by the stepwise assembly of triple-stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid-base interactions. The organocatalyst-loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. High-level production of C-11-carboxyl-labeled amino acids

    International Nuclear Information System (INIS)

    Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Hayes, R.L.; Butler, T.A.; Callahan, A.P.

    1979-01-01

    Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period

  9. Photophysics of indole-2-carboxylic acid (I2C) and indole-5-carboxylic acid (I5C): Heavy atom effect

    Science.gov (United States)

    Kowalska-Baron, Agnieszka; Gałęcki, Krystian; Wysocki, Stanisław

    2013-12-01

    In this study the effect of carboxylic group substitution in the 2 and 5 position of indole ring on the photophysics of the parent indole chromophore has been studied. The photophysical parameters crucial in triplet state decay mechanism of aqueous indole-2-carboxylic acid (I2C) and indole-5-carboxylic acid (I5C) have been determined applying our previously proposed methodology based on the heavy atom effect and fluorescence and phosphorescence decay kinetics [Kowalska-Baron et al., 2012]. The determined time-resolved phosphorescence spectra of I2C and I5C are red-shifted as compared to that of the parent indole. This red-shift was especially evident in the case of I2C and may indicate the possibility of hydrogen bonded complex formation incorporating carbonyl Cdbnd O, the NH group of I2C and, possibly, surrounding water molecules. The possibility of the excited state charge transfer process and the subsequent electronic charge redistribution in such a hydrogen bonded complex may also be postulated. The resulting stabilization of the I2C triplet state is manifested by its relatively long phosphorescence lifetime in aqueous solution (912 μs). The relatively short phosphorescence lifetime of I5C (56 μs) may be the consequence of more effective ground-state quenching of I5C triplet state. This hypothesis may be strengthened by the significantly larger value of the determined rate constant of I5C triplet state quenching by its ground-state (4.4 × 108 M-1 s-1) as compared to that for indole (6.8 × 107 M-1 s-1) and I2C (2.3 × 107 M-1 s-1). The determined bimolecular rate constant for triplet state quenching by iodide kqT1 is equal to 1 × 104 M-1 s-1; 6 × 103 M-1 s-1 and 2.7 × 104 M-1 s-1 for indole, I2C and I5C, respectively. In order to obtain a better insight into iodide quenching of I2C and I5C triplet states in aqueous solution, the temperature dependence of the bimolecular rate constants for iodide quenching of the triplet states has been expressed in

  10. Potentiometric studies on mixed-ligand chelates of uranyl ion with carboxylic acid phenolic acids

    International Nuclear Information System (INIS)

    Bandiwadekar, S.P.; Chavar, A.M.

    1988-01-01

    Mixed ligand complexes of UO 2 2+ with bidentate carboxylic and phenolic acids have been studied potentiometrically at 30 ± 0.1degC and μ=0.2M (NaClO 4 ). 1:1 and 1:2 complexes of UO 2 2+ with phthalic acid (PTHA), maleic acid (MAE), malonic acid (MAL), quinolinic acid (QA), 5-sulphosalicylic acid (5-SSA), salicylic acid (SA), and only 1:1 complexes in the case of mandelic acid (MAD) have been detected. The formation of 1:1:1 mixed ligand complexes has been inferred from simultaneous equilibria in the present study. The values of ΔlogK, Ksub(DAL), Ksub(2LA) or Ksub(2AL) for the ternary complexes have been calculated. The stabilities of mixed ligand complexes depend on the size of the chelate ring and the stabilities of the binary complexes. (author). 15 refs

  11. Luminescent Lariat Aza-Crown Ether Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Burkhard König

    2010-03-01

    Full Text Available Lariat ethers are interesting recognition motifs in supramolecular chemistry. The synthesis of a luminescent lariat aza-crown ether with a carboxyl group appended by azide-alkyne (Huisgen cycloaddition is presented.

  12. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Poole, Loree Joanne [Univ. of California, Berkeley, CA (United States); King, C. Judson [Univ. of California, Berkeley, CA (United States)

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO2 and H2S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The

  13. The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

    Science.gov (United States)

    Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia

    2011-08-01

    The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

  14. Direct enantioselective conjugate addition of carboxylic acids with chiral lithium amides as traceless auxiliaries.

    Science.gov (United States)

    Lu, Ping; Jackson, Jeffrey J; Eickhoff, John A; Zakarian, Armen

    2015-01-21

    Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B.

  15. Ru(II)-Catalyzed Oxidative Heck-Type Olefination of Aromatic Carboxylic Acids with Styrenes through Carboxylate-Assisted C-H Bond Activation.

    Science.gov (United States)

    Dana, Suman; Mandal, Anup; Sahoo, Harekrishna; Mallik, Sumitava; Grandhi, Gowri Sankar; Baidya, Mahiuddin

    2018-02-02

    A straightforward synthesis of 2-styrylbenzoic acids from aryl carboxylic acids is disclosed through a carboxylate-assisted coupling under Ru(II) catalysis. This protocol is simple and exhibits broad scope with high tolerance of common organic functional groups, providing good to excellent yields of diverse olefinated products. The efficacy of this protocol has been showcased through sequential syntheses of isochromanone, isocoumarin, and formal synthesis of anacardic acid derivative in good yields.

  16. Influence of indium-tin oxide surface structure on the ordering and coverage of carboxylic acid and thiol monolayers

    International Nuclear Information System (INIS)

    Cerruti, Marta; Rhodes, Crissy; Losego, Mark; Efremenko, Alina; Maria, Jon-Paul; Fischer, Daniel; Franzen, Stefan; Genzer, Jan

    2007-01-01

    This paper analyses the variability of self-assembled monolayers (SAMs) formation on ITO depending on the substrate surface features. In particular, we report on the formation of carboxylic acid- and thiol-based SAMs on two lots of commercially prepared indium-tin oxide (ITO) thin films. Contact angle measurements, electrochemical experiments, and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy showed that the quality of monolayers formed differed substantially between the two ITO batches. Only one of the two ITO substrates was capable of forming well-organized thiol- and carboxylic acid-based SAMs. In order to rationalize these observations, atomic force microscopy and x-ray diffraction analyses were carried out, and SAMs were prepared on ITO substrates fabricated by sputtering in our laboratories. An attempt was made to influence the film microstructure and surface morphology by varying substrate temperatures during ITO deposition. Good-quality thiol and carboxylic acid SAMs were obtained on one of the ITO substrates prepared in-house. While our characterization could not single out conclusively one specific parameter in ITO surface structure that could be responsible for good SAMs formation, we could point out homogeneous surface morphology as a relevant factor for the quality of the SAMs. Evidence was also found for ITO crystallographic orientation to be a parameter influencing SAMs organization

  17. Adsorption Equilibrium Equation of Carboxylic Acids on Anion-Exchange Resins in Water.

    Science.gov (United States)

    Kanazawa, Nobuhiro; Urano, Kohei; Kokado, Naohiro; Urushigawa, Yoshikuni

    2001-06-01

    The adsorption of propionic acid and benzoic acid on anion-exchange resins was analyzed, and an adsorption equilibrium equation of carboxylic acids was proposed. The adsorption of carboxylic acids on the anion-exchange resins was considered to be the sum of the physical adsorption of the molecule and the ion-exchange adsorption of the ion, which were independent of each other. For the physical adsorption of carboxylic acids, it was conformed to the Freundlich equation. For the ion-exchange adsorption of carboxylate ions, the equilibrium equation corresponded well with the experimental results for wide ranges of concentration and pH. The equation contains a selectivity coefficient S(A)(Cl) for the chloride ion versus the carboxylate ion, which was considered essentially a constant. The influent of the bicarbonate ion from carbon dioxide in air could also be expressed by the additional equilibrium equation with the selectivity coefficient S(HCO(3))(Cl) for the chloride ion versus the bicarbonate ion. Consequently, an adsorption equilibrium equation can estimate the equilibrium adsorption amounts. Even the effect of a coexisting bicarbonate ion is inconsequential when the parameters of the Freundlich isotherm equation and the selectivity coefficients of the carboxylate ion and the bicarbonate ion in each resin are determined in advance. Copyright 2001 Academic Press.

  18. Sorption of carboxylic acid from carboxylic salt solutions at pHs close to or above the pK[sub a] of the acid, with regeneration with an aqueous solution of ammonia or low-molecular-weight alkylamine

    Science.gov (United States)

    King, C.J.; Tung, L.A.

    1992-07-21

    Carboxylic acids are sorbed from aqueous feedstocks at pHs close to or above the acids' pH[sub a] into a strongly basic organic liquid phase or onto a basic solid adsorbent or moderately basic ion exchange resin. The acids are freed from the sorbent phase by treating it with aqueous alkylamine or ammonia thus forming an alkylammonium or ammonium carboxylate which dewatered and decomposed to the desired carboxylic acid and the alkylamine or ammonia. 8 figs.

  19. Metabolism of cyclohexane carboxylic acid by the photosynthetic bacterium Rhodopseudomonas palustris.

    Science.gov (United States)

    Küver, J; Xu, Y; Gibson, J

    1995-11-01

    Cyclohexane carboxylate supported relatively rapid growth (doubling times 7-8 h) of Rhodopseudomonas palustris under oxic or photosynthetic conditions, but did not serve as a substrate for either of the known aromatic CoA ligases. A CoA ligase that thioesterifies cyclohexane carboxylate was partially purified and did not cross react immunologically with the two CoA ligases purified previously from this bacterium. Crude extracts of R. palustris cells grown with a range of aromatic or alicyclic acids contained a dehydrogenase that reacted with cyclohexane carboxyl-CoA or cyclohex-1-ene carboxyl-CoA, using 2,6-dichlorophenolindophenol or ferricenium ion as electron carrier. This activity was not detected in extracts of adipate-, glutamate-, or succinate-grown cells. No oxidation or reduction of nonesterified cyclohexane carboxylate or cyclohexene carbocylate was detected in extracts of cells grown with aromatic or aliphatic substrates, neither aerobically nor anaerobically. A constitutively expressed thioesterase that hydrolyzed cyclohexane carboxyl-CoA and also some alicyclic and aliphatic CoA derivatives was purified and characterized. The enzyme had little or no activity on benzoyl-CoA or 4-hydroxybenzoyl-CoA. The presence of a thioesterase that effectively hydrolyzes cyclohexane carboxyl-CoA suggests that transient production of cyclohexane carboxylate is a physiological response to temporary excess of reductant during metabolism of aromatic compounds.

  20. Thermal stability of carboxylic acid functionality in coal; Sekitanchu ni sonzaisuru karubokishiruki no netsubunkai kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Y.; Aida, T. [Kinki University, Osaka (Japan). Faculty of Engineering

    1996-10-28

    Carboxyl in coal was focused in discussing its pyrolytic behavior while tracking change of its absolute amount relative to the heating temperatures. A total of four kinds of coals, consisting of two kinds brown coals, sub-bituminous coal and bituminous coal were used. Change in the absolute amount of carboxyl due to heating varies with coalification degree. Decomposition starts in the bituminous coal from around 300{degree}C, and is rapidly accelerated when 400{degree}C is exceeded. Carboxyls in brown coals exist two to three times as much as those in bituminous and sub-bituminous coals, of which 40% is decomposed at a temperature as low as about 300{degree}C. Their pyrolytic behavior at temperatures higher than 400{degree}C resembles that of the bituminous coal. Carboxyls consist of those easy to decompose and difficult to decompose. Aromatic and aliphatic carboxylic acids with simple structure are stable at temperatures lower than 300{degree}C, and decompose abruptly from about 400{degree}C, hence their behavior resembles that of carboxyls in bituminous and sub-bituminous coals. Structure of low-temperature decomposing carboxyls in brown coals is not known, but it is assumed that humic acid originated from natural materials remains in the structure. 4 refs., 3 figs., 1 tab.

  1. Accumulation potentials of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays).

    Science.gov (United States)

    Krippner, Johanna; Falk, Sandy; Brunn, Hubertus; Georgii, Sebastian; Schubert, Sven; Stahl, Thorsten

    2015-04-15

    Uptake of perfluoroalkyl acids (PFAAs) by maize represents a potential source of exposure for humans, either directly or indirectly via feed for animals raised for human consumption. The aim of the following study was, therefore, to determine the accumulation potential of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays). Two different concentrations of PFAAs were applied as aqueous solution to the soil to attain target concentrations of 0.25 mg or 1.00 mg of PFAA per kg of soil. Maize was grown in pots, and after harvesting, PFAA concentrations were measured in the straw and kernels of maize. PFCA and PFSA concentrations of straw decreased significantly with increasing chain length. In maize kernels, only PFCAs with a chain length ≤ C8 as well as perfluorobutanesulfonic acid (PFBS) were detected. The highest soil-to-plant transfer for both straw and kernels was determined for short-chained PFCAs and PFSAs.

  2. Structural basis for substrate recognition in the salicylic acid carboxyl methyltransferase family.

    Science.gov (United States)

    Zubieta, Chloe; Ross, Jeannine R; Koscheski, Paul; Yang, Yue; Pichersky, Eran; Noel, Joseph P

    2003-08-01

    Recently, a novel family of methyltransferases was identified in plants. Some members of this newly discovered and recently characterized methyltransferase family catalyze the formation of small-molecule methyl esters using S-adenosyl-L-Met (SAM) as a methyl donor and carboxylic acid-bearing substrates as methyl acceptors. These enzymes include SAMT (SAM:salicylic acid carboxyl methyltransferase), BAMT (SAM:benzoic acid carboxyl methyltransferase), and JMT (SAM:jasmonic acid carboxyl methyltransferase). Moreover, other members of this family of plant methyltransferases have been found to catalyze the N-methylation of caffeine precursors. The 3.0-A crystal structure of Clarkia breweri SAMT in complex with the substrate salicylic acid and the demethylated product S-adenosyl-L-homocysteine reveals a protein structure that possesses a helical active site capping domain and a unique dimerization interface. In addition, the chemical determinants responsible for the selection of salicylic acid demonstrate the structural basis for facile variations of substrate selectivity among functionally characterized plant carboxyl-directed and nitrogen-directed methyltransferases and a growing set of related proteins that have yet to be examined biochemically. Using the three-dimensional structure of SAMT as a guide, we examined the substrate specificity of SAMT by site-directed mutagenesis and activity assays against 12 carboxyl-containing small molecules. Moreover, the utility of structural information for the functional characterization of this large family of plant methyltransferases was demonstrated by the discovery of an Arabidopsis methyltransferase that is specific for the carboxyl-bearing phytohormone indole-3-acetic acid.

  3. Enhanced detection of amino acids in hydrophilic interaction chromatography electrospray tandem mass spectrometry with carboxylic acids as mobile phase additives.

    Science.gov (United States)

    Yin, Dengyang; Hu, Xunxiu; Liu, Dantong; Du, Wencheng; Wang, Haibo; Guo, Mengzhe; Tang, Daoquan

    2017-06-01

    Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys. In particular, the diacids have better performance than single acids. The proposed mechanism is that the diacid has hydrogen bond interaction with amino acids to reduce their polarity/amphiprotic characteristics. Besides, oxalic acid has been found having better enhancement than phthalic acid by overall consideration. Therefore, we successfully quantified the 15 amino acids in Sepia bulk pharmaceutical chemical by using oxalic acid as the additive.

  4. Extraction of rare earths by 2-ethylhexyl-carboxylic acid from various media

    International Nuclear Information System (INIS)

    Danilov, N.A.; Korpusov, G.V.; Utkina, O.B.; Pogorel'skaya, S.A.

    1992-01-01

    Certain physicochemical properties of 2-ethylhexylcarboxylic acid (2EHCA) are determined. These are the ionization constant in water, the distribution and dimerization constants in dodecane and toluene, and the solubility in water. The solubility of rare earth (RE) carboxylates in 2EHCA solutions of higher α, α-branched carboxylic acids (HIC-11), naphthenic acids, in dodecane, toluene, and tetrachloroethylene is measured. The selectivity of RE extraction by 2 EHCA from nitrate, chloride, and sulfate media is investigated. It is demonstrated that the selectivity of RE extraction changes in the order NO 3 - > Cl - > NCS - , SO 2- 4

  5. Production of alpha-hydroxy carboxylic acids and esters from higher sugars using tandem catalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    Orazov, Marat; Davis, Mark E.

    2017-11-07

    The present disclosure is directed to methods and composition used in the preparation of alpha-hydroxy carboxylic acids and esters from higher sugars using a tandem catalyst system comprising retro-aldol catalysts and Lewis acid catalysts. In some embodiments, these alpha-hydroxy carboxylic acids may be prepared from pentoses and hexoses. The retro-aldol and Lewis catalysts may be characterized by their respective ability to catalyze a 1,2-carbon shift reaction and a 1,2-hydride shift reaction on an aldose or ketose substrate.

  6. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan G., E-mail: gmalecki@us.edu.pl [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Łakomska, Iwona, E-mail: iwolak@chem.umk.pl [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Maroń, Anna [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Szala, Marcin [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland); Fandzloch, Marzena [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Nycz, Jacek E., E-mail: jacek.nycz@us.edu.pl [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland)

    2015-05-15

    The pseudotetrahedral complexes of [Cu(PPh{sub 3}){sub 2}(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh{sub 3}){sub 2}(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%.

  7. Ascorbic acid absorption in Crohn's disease. Studies using L-[carboxyl-14C]ascorbic acid

    International Nuclear Information System (INIS)

    Pettit, S.H.; Shaffer, J.L.; Johns, C.W.; Bennett, R.J.; Irving, M.H.

    1989-01-01

    Total body pool and intestinal absorption of ascorbic acid were studied in 12 patients undergoing operation for Crohn's disease (six with fistulae and six without) and in six control patients undergoing operation for reasons other than Crohn's disease. L-[carboxyl- 14 C]Ascorbic acid, 0.19-0.40 megabecquerels (MBq), was given orally. After a period of equilibration, the labeled ascorbic acid was flushed out of the patient's body tissues using large doses of unlabeled ascorbic acid. Intestinal absorption of ascorbic acid, assessed from the total cumulative urinary 14 C recovery, was found to be similar in patients with fistulizing Crohn's disease (73.9 +/- 8.45%), those without fistulas (72.8 +/- 11.53%), and in controls (80.3 +/- 8.11%). Total body pools of ascorbic acid, calculated using the plasma 14 C decay curves, were similar in patients with Crohn's disease with fistulas (17.1 +/- 5.91 mg/kg), patients without fistulas (9.6 +/- 3.58 mg/kg), and in controls (13.3 +/- 4.28 mg/kg). The results indicate that ascorbic acid absorption is normal in patients with both fistulizing and nonfistulizing Crohn's disease. The results suggest that routine supplements of vitamin C are not necessary unless oral ascorbic acid intake is low

  8. In situ infrared spectroscopic analysis of the adsorption of aromatic carboxylic acids to TiO 2, ZrO 2, Al 2O 3, and Ta 2O 5 from aqueous solutions

    Science.gov (United States)

    Dobson, Kevin D.; McQuillan, A. James

    2000-02-01

    In situ infrared spectroscopy has been used to investigate the adsorption of a range of simple aromatic carboxylic acids from aqueous solution to metal oxides. Thin films of TiO 2, ZrO 2, Al 2O 3 and Ta 2O 5 were prepared by evaporation of aqueous sols on single reflection ZnSe prisms. Benzoic acid adsorbed very strongly to ZrO 2, in a bridging bidentate fashion, but showed only weak adsorption to TiO 2 and Ta 2O 5. Substituted aromatic carboxylic acids; salicylic, phthalic and thiosalicylic, were found to adsorb to each metal oxide. Salicylic and phthalic acids adsorbed to the metal oxides via bidentate interactions, involving coordination through both carboxylate and substituent groups. Thiosalicylic acid adsorbed to the metal oxides as a bridging bidentate carboxylate with no coordination through the thiol substituent group.

  9. Design, synthesis and evaluation of 3-quinoline carboxylic acids as new inhibitors of protein kinase CK2.

    Science.gov (United States)

    Syniugin, Anatolii R; Ostrynska, Olga V; Chekanov, Maksym O; Volynets, Galyna P; Starosyla, Sergiy A; Bdzhola, Volodymyr G; Yarmoluk, Sergiy M

    2016-01-01

    In this article, the derivatives of 3-quinoline carboxylic acid were studied as inhibitors of protein kinase CK2. Forty-three new compounds were synthesized. Among them 22 compounds inhibiting CK2 with IC 50 in the range from 0.65 to 18.2 μM were identified. The most active inhibitors were found among tetrazolo-quinoline-4-carboxylic acid and 2-aminoquinoline-3-carboxylic acid derivatives.

  10. Synthesis and HPLC evaluation of carboxylic acid phases on a hydride surface.

    Science.gov (United States)

    Pesek, Joseph J; Matyska, Maria T; Gangakhedkar, Surekha; Siddiq, Rukhsana

    2006-04-01

    Three organic moieties containing carboxylic acid functional groups are attached to a particulate silica surface through silanization/hydrosilation. Two compounds (undecylenic acid and 10-undecynoic acid) have 11 carbon chains and the other is a five-carbon acid (pentenoic acid). Bonding is confirmed through carbon elemental analysis, diffuse reflectance infrared fourier transform spectroscopy, and carbon-13 and silicon-29 CP-MAS NMR spectroscopy. The bonded phases are tested by HPLC using PTH amino acids, nucleic acids, theophylline-related compounds, anilines, benzoic acid compounds, choline, and tobramycin. The latter two compounds are used to investigate the aqueous normal phase properties of the three bonded materials.

  11. Deep eutectic solvents formed between choline chloride and carboxylic acids: versatile alternatives to ionic liquids.

    Science.gov (United States)

    Abbott, Andrew P; Boothby, David; Capper, Glen; Davies, David L; Rasheed, Raymond K

    2004-07-28

    Deep Eutectic Solvents (DES) can be formed between a variety of quaternary ammonium salts and carboxylic acids. The physical properties are significantly affected by the structure of the carboxylic acid but the phase behavior of the mixtures can be simply modeled by taking account of the mole fraction of carboxylic acid in the mixture. The physical properties such as viscosity, conductivity, and surface tension of these DES are similar to ambient temperature ionic liquids and insight into the cause of these properties is gained using hole-theory. It is shown that the conductivity and viscosity of these liquids is controlled by ion mobility and the availability of voids of suitable dimensions, and this is consistent with the fluidity of other ionic liquids and molten salts. The DES are also shown to be good solvents for metal oxides, which could have potential application for metal extraction.

  12. Carboxylic acid effects on the size and catalytic activity of magnetite nanoparticles.

    Science.gov (United States)

    Hosseini-Monfared, Hassan; Parchegani, Fatemeh; Alavi, Sohaila

    2015-01-01

    Magnetite nanoparticles (Fe3O4-NPs) were successfully synthesized in diethylene glycol in the presence of carboxylic acids. They were characterized using XRD, SEM and FTIR. Carboxylic acid plays a critical role in determining the morphology, particle size and size distribution of the resulting particles. The results show that as-prepared magnetite nanoparticles are monodisperse and highly crystalline. The nanoparticles can be easily dispersed in aqueous media and other polar solvents due to coated by a layer of hydrophilic polyol and carboxylic acid ligands in situ. Easily prepared Fe3O4-NPs have been shown to be an active, recyclable, and highly selective catalyst for the epoxidation of cyclic olefins with aqueous 30% H2O2. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Rare earth separation process by liquid-liquid extraction using halogenated diluent or carboxylic acids as diluents

    International Nuclear Information System (INIS)

    Leveque, A.

    1989-01-01

    The extracting agent comprises an organophosphonic acid or phosphinic acid but instead of paraffinic hydrocarbons as diluent halogenated hydrocarbons or carboxylic acid are claimed to improve reextraction of rare earths from the organic phase [fr

  14. Silver-Catalyzed Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols

    DEFF Research Database (Denmark)

    Ghalehshahi, Hajar Golshadi; Madsen, Robert

    2017-01-01

    into the acid with HCl. The reaction can be applied to a variety of benzylic and aliphatic primary alcohols with alkyl and ether substituents, and in some cases halide, olefin, and ester functionalities are also compatible with the reaction conditions. The dehydrogenation is believed to be catalyzed by silver......A simple silver-catalyzed protocol has been developed for the acceptorless dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The procedure uses 2.5 % Ag2 CO3 and 2.5-3 equiv of KOH in refluxing mesitylene to afford the potassium carboxylate which is then converted...

  15. Nucleosides of 4-methylthio-1,2,3-triazol-5-yl-carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Shingarova, I.D.; Yartseva, I.V.; Preobrazhenskaya, M.N.

    1987-01-01

    2-β-D-Ribofuranosyl-4-methylthio-5-methoxycarbonyl-1,2,3-triazole was obtained by fusing 4-methylthio-5-methoxycarbonyl-1,2,3-triazole together with tetraacyl-D-ribofuranose, followed by deacylation, and its amide and hydrazide were prepared. The structures of the new nucleosides were established by converting them into known 2-nucleosides of 1,2,3-triazol-4-yl-carboxylic acid derivatives. By comparing PMR spectra with previously reported PMR spectra for the isomeric 1- and 2-nucleosides of 1,2,3-triazol-4-yl-carboxylic acid derivatives, the synthesized nucleosides could be assigned to 2-substituted triazoles

  16. Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes

    Science.gov (United States)

    Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

    2013-02-01

    The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

  17. Sodium borohydride reduction of aromatic carboxylic acids via ...

    Indian Academy of Sciences (India)

    -step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.

  18. Merging Photoredox and Nickel Catalysis: Decarboxylative Cross-Coupling of Carboxylic Acids with Vinyl Halides

    Science.gov (United States)

    2015-01-01

    Decarboxylative cross-coupling of alkyl carboxylic acids with vinyl halides has been accomplished through the synergistic merger of photoredox and nickel catalysis. This new methodology has been successfully applied to a variety of α-oxy and α-amino acids, as well as simple hydrocarbon-substituted acids. Diverse vinyl iodides and bromides give rise to vinylation products in high efficiency under mild, operationally simple reaction conditions. PMID:25521443

  19. Synthesis of 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Elhadi, S. A.

    2004-09-01

    Quinolin derivatives are a group of compounds known to possess a wide range of biological activities. The chemistry of quinolines together with their corresponding aldehydes were dealt with in chapter one of this study. Special emphasis was given to the chemistry of benzaldehyde. Twenty five 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives together with their corresponding intermediates were prepared in this work. Basically, the synthetic design of these compounds arise from the appropriate disconnections of the target 2-phenyl and 2,3-diphenyl-quinolin-4-carboxylic acids. The retro synthesis analysis of these compounds reveals pyruvic acid, aromatic amine and benzaldehyde or phenyl pyruvic acid, aromatic amine and benzaldehyde as possible logical precursors for 2-phenyl-and 2,3-diphenyl- quinoline-4-carboxylic acids respectively. The purity and identities of the synthesized compounds were elucidated through chromatographic and spectroscopic techniques. The compounds were heavily subjected to spectroscopic analysis (UV, IR, GC/MS, 1 H-and 13 C- NMR). The appropriate disconnections and the mechanisms of the corresponding reactions were given and discussed in chapter three. The spectral data were interpreted and correlated with the target structures. The prepared 2-phenyl- and 2,3-diphenyl-quinoline-4-carboxylic acid derivatives were screened for their antibacterial activity. The compounds were tested against the standard bacterial organisms B. subtilis, S. aureus, E. coli and P. vulgaris. Some of these compounds were devoid of antibacterial activity against S. aureus and P. vulgaris, while others showed moderate activity. All of the tested compounds showed an activity against B. subtilis and E. coli. 2,3-diphenyl -6-sulphanilamide-quinolin-4-carboxylic acid showed the highest activity against the four standard tested organisms.(Author)

  20. Role of apparent pKa of carboxylic acids in lipase-catalyzed esterifications in biphasic systems

    NARCIS (Netherlands)

    Dominguez de Maria, Pablo; Fernandez-Alvaro, Elena; ten Kate, Antoon; Bargeman, Gerrald

    2009-01-01

    Lipase-catalyzed esterifications in biphasic media (heptane–water, 1:1) were conducted by using Thermomyces lanuginosus lipase (TLL) as biocatalyst. Different carboxylic acids (from acetic to lauric) were thus esterified with 1-butanol at different pH values (2–10). For all carboxylic acids tested,

  1. Synthesis of aminocarbonyl N-acylhydrazones by a three-component reaction of isocyanides, hydrazonoyl chlorides, and carboxylic acids.

    Science.gov (United States)

    Giustiniano, Mariateresa; Meneghetti, Fiorella; Mercalli, Valentina; Varese, Monica; Giustiniano, Francesco; Novellino, Ettore; Tron, Gian Cesare

    2014-10-17

    A novel one-pot multicomponent synthesis of α-aminocarbonyl N-acylhydrazones starting from readily available hydrazonoyl chlorides, isocyanides, and carboxylic acids is reported. The strategy exploits the ability of the carboxylic acid as a third component to suppress all competing reactions between nitrile imines and isocyanides, channeling the course of the reaction toward the formation of this novel class of compounds.

  2. Solvent-Free Esterification of Carboxylic Acids Using Supported Iron Oxide Nanoparticles as an Efficient and Recoverable Catalyst

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2016-07-01

    Full Text Available Supported iron oxide nanoparticles on mesoporous materials (FeNP@SBA-15 have been successfully utilized in the esterification of a variety carboxylic acids including aromatic, aliphatic, and long-chain carboxylic acids under convenient reaction conditions. The supported catalyst could be easily recovered after reaction completion and reused several times without any loss in activity after up to 10 runs.

  3. Enhanced Production of Carboxylic Acids by Engineering of Rhizopus

    Science.gov (United States)

    The fungus Rhizopus is frequently used to convert, or ferment sugars obtained from agricultural crops to lactic acid. This natural product has long been utilized by the food industry as an additive for preservation, flavor, and acidity. Additionally, it is used for the manufacture of environmental...

  4. Basicity of carboxylic acids: resonance in the cation and substituent effects

    Czech Academy of Sciences Publication Activity Database

    Böhm, S.; Exner, Otto

    2005-01-01

    Roč. 29, - (2005), s. 336-342 ISSN 1144-0546 R&D Projects: GA MŠk(CZ) LN00A032 Institutional research plan: CEZ:AV0Z4055905 Keywords : basicity * carboxylic acids Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.574, year: 2005

  5. Substituted Amides of Pyrazine-2-carboxylic acids: Synthesis and Biological Activity

    Directory of Open Access Journals (Sweden)

    Katarina Kralova

    2002-03-01

    Full Text Available Condensation of 6-chloro-, 5-tert-butyl- or 6-chloro-5-tert-butylpyrazine-2-carboxylic acid chloride with ring substituted anilines yielded a series of amides, which were tested for their in vitro antimycobacterial, antifungal and photosynthesis-inhibiting activities. The highest antituberculotic activity (72% inhibition against Mycobacterium tuberculosis and the highest lipophilicity (log P = 6.85 were shown by the 3,5-bistrifluoromethylphenyl amide of 5-tert-butyl-6-chloropyrazine-2-carboxylic acid (2o. The 3-methylphenyl amides of 6-chloro- and 5-tert-butyl-6-chloro-pyrazine-2-carboxylic acid (2d and 2f exhibited only a poor in vitro antifungal effect (MIC = 31.25-500 μmol·dm-3 against all strains tested, although the latter was the most active antialgal compound (IC50 = 0.063 mmol·dm-3. The most active inhibitor of oxygen evolution rate in spinach chloroplasts was the (3,5-bis-trifluoromethylphenylamide of 6-chloropyrazine-2-carboxylic acid (2m, IC50 = 0.026 mmol·dm-3.

  6. 4-(Dimethylamino)pyridine-catalysed iodolactonisation of γ,δ-unsaturated carboxylic acids.

    Science.gov (United States)

    Meng, Chuisong; Liu, Zhihui; Liu, Yuxiu; Wang, Qingmin

    2015-06-28

    4-(Dimethylamino)pyridine functioned as an excellent catalyst for iodolactonisation reactions of γ,δ-unsaturated carboxylic acids, affording γ-lactones, δ-lactones, or both under neutral conditions at room temperature. The effects of substrate structures on the iodolactonisation were investigated, and a catalytic mechanism is proposed.

  7. Kinetics of the esterification of active pharmaceutical ingredients containing carboxylic Acid functionality in polyethylene glycol

    DEFF Research Database (Denmark)

    Schou-Pedersen, Anne Marie V; Hansen, Steen Honoré; Moesgaard, Birthe

    2014-01-01

    reactions. In this study, kinetics of two active pharmaceutical ingredients, cetirizine and indomethacin possessing carboxylic acid functionality, has been studied in PEG 400 and PEG 1000 at 50°C, 60°C, 70°C, and 80°C. HPLC-UV was applied for the determination of concentrations in the kinetic studies...

  8. Synthesis of 2,2'-Dipyrryl Ketones from Pyrrole-2-carboxylic Acids with Trifluoroacetic Anhydride

    International Nuclear Information System (INIS)

    Kim, Se Hee; Lim, Jin Woo; Yu, Jin; Kim, Jae Nyoung

    2013-01-01

    An efficient synthesis of 2,2'-dipyrryl ketones has been carried out from pyrrole-2-carboxylic acids using trifluoroacetic anhydride (TFAA). Simultaneous generation of both mixed anhydride and 2-unsubstituted pyrrole, via facile decarboxylation with in-situ generated TFA, made their cross reaction (intermolecular Friedel-Crafts acylation) possible and efficient

  9. Growth kinetics of racemic heptahelicene-2-carboxylic acid nanowires on calcite (104)

    Czech Academy of Sciences Publication Activity Database

    Einax, M.; Richter, T.; Nimmrich, M.; Rahe, P.; Stará, Irena G.; Starý, Ivo; Kühnle, A.; Maass, P.

    2016-01-01

    Roč. 145, č. 13 (2016), č. článku 134702. ISSN 0021-9606 Institutional support: RVO:61388963 Keywords : heptahelicene-2-carboxylic acid nanowires * nc-AFM * calcite * growth kinetics Subject RIV: CC - Organic Chemistry Impact factor: 2.965, year: 2016

  10. Sorption of carboxylic acid from carboxylic salt solutions at PHS close to or above the pK.sub.a of the acid, with regeneration with an aqueous solution of ammonia or low-molecular-weight alkylamine

    Science.gov (United States)

    King, C. Judson; Tung, Lisa A.

    1992-01-01

    Carboxylic acids are sorbed from aqueous feedstocks at pHs close to or above the acids' pH.sub.a into a strongly basic organic liquid phase or onto a basic solid adsorbent or moderately basic ion exchange resin. the acids are freed from the sorbent phase by treating it with aqueous alkylamine or ammonia thus forming an alkylammonium or ammonium carobxylate which dewatered and decomposed to the desired carboxylic acid and the alkylamine or ammonia.

  11. Effects of carboxylic acids on nC60 aggregate formation

    International Nuclear Information System (INIS)

    Chang Xiaojun; Vikesland, Peter J.

    2009-01-01

    The discovery that negatively charged aggregates of C 60 fullerene (nC 60 ) are stable in water has raised concerns regarding the potential environmental and health effects of these aggregates. In this work, we show that nC 60 aggregates produced by extended mixing in the presence of environmentally relevant carboxylic acids (acetic acid, tartaric acid, citric acid) have surface charge and morphologic properties that differ from those produced by extended mixing in water alone. In general, aggregates formed in the presence of these acids have a more negative surface charge and are more homogeneous than those produced in water alone. Carboxylic acid identity, solution pH, and sodium ion concentration, which are all intricately coupled, play an important role in setting the measured surface charge. Comparisons between particle sizes determined by analysis of TEM images and those obtained by dynamic light scattering (DLS) indicate that DLS results require careful evaluation when used to describe nC 60 aggregates. - The effects of carboxylic acids on the formation of nC 60 aggregates are discussed

  12. Kinetic studies on the carboxylation of 6-amino-penicillanic acid to 8-hydroxy-penillic acid

    DEFF Research Database (Denmark)

    Henriksen, Claus Maxel; Holm, SS; Schipper, D.

    1997-01-01

    The carboxylation in aqueous solution of 6-amino-penicillanic acid (6-APA) to 8-hydroxy-penillic acid (8-HPA) was studied at 25 degrees C and pH 6.5. During sparging with either a citrate buffer or a chemically defined cultivation medium containing 6-APA with mixtures of carbon dioxide and air (2....... Formation of the unknown compound was not observed in the cultivation medium. The carboxylation of 6-APA was also found to be first order with respect to the concentration of dissolved carbon dioxide. The rate constant for formation of 8-HPA did not differ significantly in the cultivation medium compared...

  13. In situ infrared spectroscopic analysis of the adsorption of aliphatic carboxylic acids to TiO 2, ZrO 2, Al 2O 3, and Ta 2O 5 from aqueous solutions

    Science.gov (United States)

    Dobson, Kevin D.; McQuillan, A. James

    1999-07-01

    The adsorption of a range of aliphatic mono- and di-carboxylic acids to metal oxides has been investigated using in situ attenuated total reflectance infrared spectroscopy. Thin films of TiO 2, ZrO 2, Al 2O 3, and Ta 2O 5 were prepared by evaporation the aqueous colloid oxides on single reflection ZnSe prisms. Formic and acetic acids were found to bind to ZrO 2 and Ta 2O 5, but showed no adsorption to TiO 2 and Al 2O 3. The dicarboxylic acids, oxalic, malonic, succinic, adipic, maleic, and fumaric acids, were found to adsorb to each of the metal oxide substrates. Oxalic and malonic acids were coordinated via ester linkages involving both carboxylate groups. The longer chain dicarboxylic acids coordinated via bridging bidentate interactions through each carboxylate group.

  14. Molybdenum (5) complexes with glycine and pyridine carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V.I.; Felin, M.G.; Subbotina, N.A.; Ajzenberg, M.I.; Mozgin, S.V. (Moskovskij Gosudarstvennyj Univ. (USSR))

    1984-03-01

    Mo/sub 2/O/sub 3/Cl/sub 4/ (gly H)/sub 4/ (gly H=NH/sub 2/CH/sub 2/COOH) and (LH)/sub 4/M..omega../sub 2/O/sub 3/Cl/sub 8/x4H/sub 2/O complexes (L=picolinic, nicotinic, isonicotinic acids) are prepared during the interaction of molybdenum (3) hydrochloride with the corresponding organic acids. Their composition is determined by a chemical analysis. The rate of molybdenum oxidation is established based on the IR- and electron spectroscopy data as well as from measuring the magnetic susceptibility. The composition of synthesized compounds is suggested. The thermal behaviour of the prepared complexes is studied, and an intermediate product of dehydrohalogenation is extracted on the example of a compound with isonicotinic acid.

  15. Chemical states of p-boronophenylalanine in aqueous carboxylic acids and polyols

    International Nuclear Information System (INIS)

    Kobayashi, Mitsue; Kitaoka, Yoshinori

    1995-01-01

    Chemical states of p-boronophenylalanine were studied by infrared (IR) spectroscopy in aqueous carboxylic acids and in aqueous fructose. For BPA in water, the absorption band due to the B-O stretching of trigonal boron was observed, while that of tetrahedral boron was observed for BPA in aqueous oxalic acid. This means BPA forms a complex of tetrahedral boron with oxalate. It was proved that BPA also formed complexes of tetrahedral boron with citric acid as well as with fructose. No appreciable interaction was detected between BPA and maleic acid. (author)

  16. Synthesis and Optical Properties of Pentamethine Cyanine Dyes With Carboxylic Acid Moieties

    Directory of Open Access Journals (Sweden)

    Tyler L Dost

    2017-05-01

    Full Text Available Cyanine dyes possessing carboxylic acid groups have been used in many different fields of study. The acid groups can act as handles for bioconjugation or as metal chelators. Several pentamethine cyanine dyes with propionic acid handles were synthesized and their optical properties were studied to determine their usefulness as fluorescent probes. The optical properties studies performed include the absorbance and emission maxima values as well as the calculation of quantum yield and molecular brightness levels. Molecular models were also calculated to help analyze the dyes’ behavior and were compared with similar dyes with varying alkyl chain lengths replacing the acid moieties.

  17. Arginine-responsive terbium luminescent hybrid sensors triggered by two crown ether carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Lasheng [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Tang, Ke; Ding, Xiaoping [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhou, Zhan; Xiao, Rui [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2013-12-01

    Crown ether carboxylic acids constitute main building blocks for the synthesis of terbium containing covalent cross-linked luminescent materials. Both the complexes and the hybrid nanomaterials could exhibit remarkable green emissions in pure water. More importantly, they were found to have a profound effect on the luminescence responses to arginine compared with glutamic acid, histidine, tryptophan, threonine, tyrosine and phenylalanine in aqueous environment. The present study provided the possibility of using a host–guest mechanism as a way of signal transduction based on lanthanide supramolecular hybrid materials. - Highlights: • Crown ether carboxylic acids were found to sensitize terbium ions among a group of ethers. • The complexes and silica hybrid materials were both prepared and characterized. • They could exhibit remarkable green emissions in pure water.

  18. Design, Synthesis, Antimycobacterial Evaluation, and In Silico Studies of 3-(Phenylcarbamoyl-pyrazine-2-carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Lucia Semelková

    2017-09-01

    Full Text Available Pyrazinamide, the first-line antitubercular drug, has been regarded the basic component of tuberculosis treatment for over sixty years. Researchers have investigated its effect on Mycobacterium tuberculosis for this long time, and as a result, new potential targets of pyrazinamide or its active form, pyrazinoic acid, have been found. We have designed and prepared 3-(phenyl-carbamoylpyrazine-2-carboxylic acids as more lipophilic derivatives of pyrazinoic acid. We also prepared methyl and propyl derivatives as prodrugs with further increased lipophilicity. Antimycobacterial, antibacterial and antifungal growth inhibiting activity was investigated in all prepared compounds. 3-[(4-Nitrophenylcarbamoyl]pyrazine-2-carboxylic acid (16 exerted high antimycobacterial activity against Mycobacterium tuberculosis H37Rv with MIC = 1.56 μg·mL−1 (5 μM. Propyl 3-{[4-(trifluoromethylphenyl]carbamoyl}pyrazine-2-carboxylate (18a showed also high antimycobacterial activity against Mycobacterium tuberculosis H37Rv with MIC = 3.13 μg·mL−1. In vitro cytotoxicity of the active compounds was investigated and no significant cytotoxic effect was observed. Based to structural similarity to known inhibitors of decaprenylphosphoryl-β-d-ribose oxidase, DprE1, we performed molecular docking of the prepared acids to DprE1. These in silico experiments indicate that modification of the linker connecting aromatic parts of molecule does not have any negative influence on the binding.

  19. On the formation of niacin (vitamin B3) and pyridine carboxylic acids in interstellar model ices

    Energy Technology Data Exchange (ETDEWEB)

    McMurtry, Brandon M.; Turner, Andrew M.; Saito, Sean E.J.; Kaiser, Ralf I. [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI 96822 (United States); Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI 96822 (United States)

    2016-06-15

    The formation of pyridine carboxylic acids in interstellar ice grains was simulated by electron exposures of binary pyridine (C{sub 5}H{sub 5}N)-carbon dioxide (CO{sub 2}) ice mixtures at 10 K under contamination-free ultrahigh vacuum conditions. Chemical processing of the pristine ice and subsequent warm-up phase was monitored on line and in situ via Fourier transform infrared spectroscopy to probe for the formation of new radiation induced species. In the infrared spectra of the irradiated ice, bands assigned to nicotinic acid (niacin; vitamin B3; m-C{sub 5}H{sub 4}NCOOH) along with 2,3-, 2,5-, 3,4-, and 3,5-pyridine dicarboxylic acid (C{sub 5}H{sub 3}N(COOH){sub 2}) were unambiguously identified along with the hydroxycarbonyl (HOCO) radical. Our study suggests that the reactive pathway responsible for pyridine carboxylic acids formation involves a HOCO intermediate, which forms through the reaction of suprathermal hydrogen ejected from pyridine with carbon dioxide. The newly formed pyridinyl radical may then undergo radical–radical recombination with a hydroxycarbonyl radical to form a pyridine carboxylic acid.

  20. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dron, Julien [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: julien.dron@up.univ-mrs.fr; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)

    2007-12-12

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF{sub 3}/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L{sup -1}. Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

  1. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

    International Nuclear Information System (INIS)

    Dron, Julien; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri

    2007-01-01

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF 3 /methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L -1 . Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices

  2. 40 CFR 180.426 - 2-[4,5-Dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinoline carboxylic acid...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false 2- -3-quinoline carboxylic acid... Tolerances § 180.426 2- -3-quinoline carboxylic acid; tolerance for residues. A tolerance is established for residues of the herbicide 2- -3-quinoline carboxylic acid, in or on the raw agricultural commodity soybean...

  3. Synthesis of metabolites of the insecticide Deltamethrine: 3-phenoxy (carboxyl-14C) benzoic acids and 3-phenoxy (hydroxymethyl-14C) benzyl alcohols

    International Nuclear Information System (INIS)

    Do-Cao-Thang; Nguyen-Hoang-Nam; Hoellinger, H.; Pichat, L.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

    1985-01-01

    Procedures are described for the synthesis of the following metabolites of Deltamethrin, the pyrethroid insecticide: 3-phenoxy (carboxyl- 14 C) benzoic acid, 3-(4'-hydroxyphenoxy) (carboxyl- 14 C) benzoic acid, 3-(2'-hydroxyphenoxy) (carboxyl- 14 C) benzoic acid and the corresponding 3-phenoxybenzyl alcohols, specific activity = 47-57 mCi/mmol. (author)

  4. Chemo-enzymatic epoxidation of olefins by carboxylic acid esters and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ruesch gen. Klaas, M.; Warwel, S. [Inst. for Biochemistry and Technology of Lipids, H.P. Kaufmanm-Inst., Federal Centre for Cereal, Potato and Lipid Research, Muenster (Germany)

    1998-12-31

    Ethylen and, recently, butadiene can be epoxidized directly with oxygen and for the epoxidation of propylene, the use of heterogeneous transition metals and organic peroxides (Halcon-Process) is the major player. But, beside from those notable exceptions, all other epoxidations, including large ones like the epoxidation of plant oils as PVC-stabilizers (about 200.000 t/year), are carried out with peroxy acids. Because mcpba is far to expensive for most applications, short chain peracids like peracetic acid are used. Being much less stable than mcpba and thus risky handled in large amounts and high concentrations, these peroxy acids were preferably prepared in-situ. However, conventional in-situ formation of peracids has the serious drawback, that a strong acid is necessary to catalyze peroxy acid formation from the carboxylic acid and hydrogen peroxide. The presence of a strong acid in the reaction mixture often results in decreased selectivity because of the formation of undesired by-products by opening of the oxirane ring. Therefore, we propose a new method for epoxidation based on the in-situ preparation of percarboxylic acids from carboxylic acid esters and hydrogen peroxide catalyzed by a commercial, immobilized lipase. (orig.)

  5. Attenuated total reflectance Fourier-transform infrared spectroscopy of carboxylic acids adsorbed onto mineral surfaces

    Science.gov (United States)

    Kubicki, J. D.; Schroeter, L. M.; Itoh, M. J.; Nguyen, B. N.; Apitz, S. E.

    1999-09-01

    A suite of naturally-occurring carboxylic acids (acetic, oxalic, citric, benzoic, salicylic and phthalic) and their corresponding sodium salts were adsorbed onto a set of common mineral substrates (quartz, albite, illite, kaolinite and montmorillonite) in batch slurry experiments. Solution pH's of approximately 3 and 6 were used to examine the effects of pH on sorption mechanisms. Attenuated total reflectance Fourier-transform infrared (ATR FTIR) spectroscopy was employed to obtain vibrational frequencies of the organic ligands on the mineral surfaces and in solution. UV/visible spectroscopy on supernatant solutions was also employed to confirm that adsorption from solution had taken place for benzoic, salicylic and phthalic acids. Molecular orbital calculations were used to model possible surface complexes and interpret the experimental spectra. In general, the tectosilicates, quartz and albite feldspar, did not chemisorb (i.e., strong, inner-sphere adsorption) the carboxylate anions in sufficient amounts to produce infrared spectra of the organics after rinsing in distilled water. The clays (illite, kaolinite and montmorillonite) each exhibited similar ATR FTIR spectra. However, the illite sample used in this study reacted to form strong surface and aqueous complexes with salicylic acid before being treated to remove free Fe-hydroxides. Chemisorption of carboxylic acids onto clays is shown to be limited without the presence of Fe-hydroxides within the clay matrix.

  6. ON THE FORMATION OF BENZOIC ACID AND HIGHER-ORDER BENZENE CARBOXYLIC ACIDS IN INTERSTELLAR MODEL ICE GRAINS

    International Nuclear Information System (INIS)

    McMurtry, Brandon M.; Saito, Sean E. J.; Turner, Andrew M.; Chakravarty, Harish K.; Kaiser, Ralf I.

    2016-01-01

    With a binary ice mixture of benzene (C 6 H 6 ) and carbon dioxide (CO 2 ) at 10 K under contamination-free ultrahigh vacuum conditions, the formation of benzene carboxylic acids in interstellar ice grains was studied. Fourier transform infrared spectroscopy was used to probe for the formation of new species during the chemical processing of the ice mixture and during the following temperature-programmed desorption. Newly formed benzene carboxylic acid species, i.e., benzoic acid, as well as meta - and para -benzene dicarboxylic acid, were assigned using newly emerging bands in the infrared spectrum; a reaction mechanism, along with rate constants, was proposed utilizing the kinetic fitting of the coupled differential equations.

  7. Solvation effects in kinetics of reactions of deuterium-hydrogen exchange with carboxylic acid

    International Nuclear Information System (INIS)

    Serebryanskaya, A.I.; Kurenkova, V.N.; Shatenshtejn, A.I.

    1980-01-01

    A comparative study of the kinetic of the reaction of deuterium-hydrogen exchange of 1,3-dideuteroazulene and 2,4,6-trideuterotrimethoxybenzene with acetic acid is carried out at a wide variation of its concentration. Peculiarities of the competitive effect of electron-donor and polar properties of aprotic solvents are pointed out. Comparison with analogous data obtained earlier for deuterium exchange of 1,4-D 2 -durene with trifluoroacetic acid permitted to find role of effects of specific and nonspecific solvation depending on medium properties and also on dissociation constant and polarity of carboxylic acid

  8. Formation routes of interstellar glycine involving carboxylic acids: possible favoritism between gas and solid phase.

    Science.gov (United States)

    Pilling, Sergio; Baptista, Leonardo; Boechat-Roberty, Heloisa M; Andrade, Diana P P

    2011-11-01

    Despite the extensive search for glycine (NH₂CH₂COOH) and other amino acids in molecular clouds associated with star-forming regions, only upper limits have been derived from radio observations. Nevertheless, two of glycine's precursors, formic acid and acetic acid, have been abundantly detected. Although both precursors may lead to glycine formation, the efficiency of reaction depends on their abundance and survival in the presence of a radiation field. These facts could promote some favoritism in the reaction pathways in the gas phase and solid phase (ice). Glycine and these two simplest carboxylic acids are found in many meteorites. Recently, glycine was also observed in cometary samples returned by the Stardust space probe. The goal of this work was to perform theoretical calculations for several interstellar reactions involving the simplest carboxylic acids as well as the carboxyl radical (COOH) in both gas and solid (ice) phase to understand which reactions could be the most favorable to produce glycine in interstellar regions fully illuminated by soft X-rays and UV, such as star-forming regions. The calculations were performed at four different levels for the gas phase (B3LYP/6-31G*, B3LYP/6-31++G**, MP2/6-31G*, and MP2/6-31++G**) and at MP2/6-31++G** level for the solid phase (ice). The current two-body reactions (thermochemical calculation) were combined with previous experimental data on the photodissociation of carboxylic acids to promote possible favoritism for glycine formation in the scenario involving formic and acetic acid in both gas and solid phase. Given that formic acid is destroyed more in the gas phase by soft X-rays than acetic acid is, we suggest that in the gas phase the most favorable reactions are acetic acid with NH or NH₂OH. Another possible reaction involves NH₂CH₂ and COOH, one of the most-produced radicals from the photodissociation of acetic acid. In the solid phase, we suggest that the reactions of formic acid with NH

  9. Separation of Aliphatic and Aromatic Carboxylic Acids by Conventional and Ultra High Performance Ion Exclusion Chromatography.

    Science.gov (United States)

    Mansour, Fotouh R; Kirkpatrick, Christine L; Danielson, Neil D

    2013-06-01

    An ion exclusion chromatography (IELC) comparison between a conventional ion exchange column and an ultra-high performance liquid chromatography (UHPLC) dynamically surfactant modified C18 column for the separation of an aliphatic carboxylic acid and two aromatic carboxylic acids is presented. Professional software is used to optimize the conventional IELC separation conditions for acetylsalicylic acid and the hydrolysis products: salicylic acid and acetic acid. Four different variables are simultaneously optimized including H 2 SO 4 concentration, pH, flow rate, and sample injection volume. Thirty different runs are suggested by the software. The resolutions and the time of each run are calculated and feed back to the software to predict the optimum conditions. Derringer's desirability functions are used to evaluate the test conditions and those with the highest desirability value are utilized to separate acetylsalicylic acid, salicylic acid, and acetic acid. These conditions include using a 0.35 m M H 2 SO 4 (pH 3.93) eluent at a flow rate of 1 mL min -1 and an injection volume of 72 μL. To decrease the run time and improve the performance, a UHPLC C18 column is used after dynamic modification with sodium dodecyl sulfate. Using pure water as a mobile phase, a shorter analysis time and better resolution are achieved. In addition, the elution order is different from the IELC method which indicates the contribution of the reversed-phase mode to the separation mechanism.

  10. Polyoxyethylene alkyl ether carboxylic acids: An overview of a neglected class of surfactants with multiresponsive properties.

    Science.gov (United States)

    Chiappisi, Leonardo

    2017-12-01

    In this work, an overview on aqueous solutions of polyoxyethylene alkyl ether carboxylic acids is given. Unique properties arise from the combination of the nonionic, temperature-responsive polyoxyethylene block with the weakly ionic, pH-responsive carboxylic acid termination in a single surfactant headgroup. Accordingly, this class of surfactant finds broad application across very different sectors. Despite their large use on an industrial and a technical scale, the literature lacks a systematic and detailed characterization of their physico-chemical properties which is provided herein. In addition, a comprehensive overview is given of their self-assembly and interfacial behavior, of their use as colloidal building blocks and for large-scale applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Preparation and reactivity of carboxylic acid-terminated boron-doped diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Niedziolka-Joensson, Joanna [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Parc de la Haute Borne, 50 Avenue de Halley, BP 70478, 59658 Villeneuve d' Ascq (France); Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, UMR 8520), Cite Scientifique, Avenue Poincare, BP 60069, 59652 Villeneuve d' Ascq (France); Boland, Susan; Leech, Donal [School of Chemistry, National University of Irland, Galway (Ireland); Boukherroub, Rabah [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Parc de la Haute Borne, 50 Avenue de Halley, BP 70478, 59658 Villeneuve d' Ascq (France); Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, UMR 8520), Cite Scientifique, Avenue Poincare, BP 60069, 59652 Villeneuve d' Ascq (France); Szunerits, Sabine, E-mail: sabine.szunerits@iri.univ-lille1.f [Institut de Recherche Interdisciplinaire (IRI, USR 3078), Parc de la Haute Borne, 50 Avenue de Halley, BP 70478, 59658 Villeneuve d' Ascq (France); Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, UMR 8520), Cite Scientifique, Avenue Poincare, BP 60069, 59652 Villeneuve d' Ascq (France)

    2010-01-01

    The paper reports on the formation of carboxy-terminated boron-doped diamond (BDD) electrodes. The carboxylic acid termination was prepared in a controlled way by reacting photochemically oxidized BDD with succinic anhydride. The resulting interface was readily employed for the linking of an amine-terminated ligand such as an osmium complex bearing an amine terminal group. The interfaces were characterized using X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Contact angle measurements were used to follow the changes in surface wetting properties due to surface functionalization. The chemical reactivity of the carboxyl-terminated BDD was investigated by covalent coupling of the acid groups to an amine-terminated osmium complex.

  12. Supramolecular Coordination Assemblies Constructed From Multifunctional Azole-Containing Carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Yuheng Deng

    2010-05-01

    Full Text Available This paper provides a brief review of recent progress in the field of metal coordination polymers assembled from azole-containing carboxylic acids and gives a diagrammatic summary of the diversity of topological structures in the resulting infinite metal-organic coordination networks (MOCNs. Azole-containing carboxylic acids are a favorable kind of multifunctional ligand to construct various metal complexes with isolated complexes and one, two and three dimensional structures, whose isolated complexes are not the focus of this review. An insight into the topology patterns of the infinite coordination polymers is provided. Analyzed topologies are compared with documented topologies and catalogued by the nature of nodes and connectivity pattern. New topologies which are not available from current topology databases are described and demonstrated graphically.

  13. Chemoselective Boron-Catalyzed Nucleophilic Activation of Carboxylic Acids for Mannich-Type Reactions.

    Science.gov (United States)

    Morita, Yuya; Yamamoto, Tomohiro; Nagai, Hideoki; Shimizu, Yohei; Kanai, Motomu

    2015-06-10

    The carboxyl group (COOH) is an omnipresent functional group in organic molecules, and its direct catalytic activation represents an attractive synthetic method. Herein, we describe the first example of a direct catalytic nucleophilic activation of carboxylic acids with BH3·SMe2, after which the acids are able to act as carbon nucleophiles, i.e. enolates, in Mannich-type reactions. This reaction proceeds with a mild organic base (DBU) and exhibits high levels of functional group tolerance. The boron catalyst is highly chemoselective toward the COOH group, even in the presence of other carbonyl moieties, such as amides, esters, or ketones. Furthermore, this catalytic method can be extended to highly enantioselective Mannich-type reactions by using a (R)-3,3'-I2-BINOL-substituted boron catalyst.

  14. Design and biological evaluation of biphenyl-4-carboxylic acid hydrazide-hydrazone for antimicrobial activity.

    Science.gov (United States)

    Deep, Aakash; Jain, Sandeep; Sharma, Prabodh Chander; Verma, Prabhakar; Kumar, Mahesh; Dora, Chander Parkash

    2010-01-01

    Seven biphenyl-4-carboxylic acid hydrazide-hydrazones have been synthesized. These hydrazone derivatives were characterized by CHN analysis, IR, and 1H NMR spectral data. All the compounds were evaluated for their in vitro antimicrobial activity against two Gram negative strains (Escherichia coli and Pseudomonas aeruginosa) and two Gram positive strains (Bacillus subtilis and Staphylococcus aureus) and fungal strain Candida albicans and Aspergillus niger All newly synthesized compounds exhibited promising results.

  15. Heterogeneous and homogeneous catalysis for the hydrogenation of carboxylic acid derivatives: history, advances and future directions.

    Science.gov (United States)

    Pritchard, James; Filonenko, Georgy A; van Putten, Robbert; Hensen, Emiel J M; Pidko, Evgeny A

    2015-06-07

    The catalytic reduction of carboxylic acid derivatives has witnessed a rapid development in recent years. These reactions, involving molecular hydrogen as the reducing agent, can be promoted by heterogeneous and homogeneous catalysts. The milestone achievements and recent results by both approaches are discussed in this Review. In particular, we focus on the mechanistic aspects of the catalytic hydrogenation and highlight the bifunctional nature of the mechanism that is preferred for supported metal catalysts as well as homogeneous transition metal complexes.

  16. N-Alkylation Using Sodium Triacetoxyborohydride with Carboxylic Acids as Alkyl Sources.

    Science.gov (United States)

    Tamura, Satoru; Sato, Keigo; Kawano, Tomikazu

    2018-01-01

    A versatile N-alkylation was performed using sodium triacetoxyborohydride and carboxylic acid as an alkyl source. The combination of these reagents furnished products different from those given previously by a similar reaction. Moreover, the mild conditions of our method allowed some functional groups to remain through the reaction, whereas they would react and be converted into other moieties in the similar reductive N-alkylation reported previously. Herein, we provide a new procedure for the preparation of various compounds containing nitrogen atoms.

  17. Aminolysis of resin-bound N-nosylaziridine-2-carboxylic acids

    DEFF Research Database (Denmark)

    Olsen, Christian A; Christensen, Caspar; Nielsen, Birgitte

    2006-01-01

    [Structure: see text] Solid-phase synthesis is a rapidly developing area of organic chemistry, of particular importance for medicinal chemistry and chemical biology. Aziridines have previously only rarely been applied in solid-phase synthesis. In the present work, aminolysis of resin-bound, spring......-loaded N-nitrobenzenesulfonyl-activated aziridine-2-carboxylic acids has been optimized and employed in the synthesis of a number of open-chain and heterocyclic scaffolds, including enantiopure products....

  18. Pyrazole carboxamides and carboxylic acids as protein kinase inhibitors in aberrant eukaryotic signal transduction

    DEFF Research Database (Denmark)

    Persson, Tobias; Yde, Christina W.; Rasmussen, Jakob Ewald

    2007-01-01

    Densely functionalised pyrazole carboxamides and carboxylic acids were synthesised in an expedient manner through saponification and transamidation, respectively, of ester-functionalised pyrazoles. This synthetic protocol allowed for three diversifying steps in which appendages on the pyrazole sc...... potential biological activity, MCF-7 human breast cancer cells were incubated with the most promising derivatives. Two analogues caused changes in MCF-7 cell growth, one of them through cell cycle arrest demonstrated by cell cycle analysis....

  19. Synthesis of N-acylurea derivatives from carboxylic acids and N,N ...

    Indian Academy of Sciences (India)

    acid 1 (scheme 1) to the basic nitrogen of the carbodi- imide 2, followed by addition of the carboxylate to form the O-acyl isourea 3. It is known10 that in low dielec- tric constant solvents such as CH2Cl2, formation of 3 occurs instantaneously and, in the absence of a nucle- ophile or a base, it can be stable for many hours.

  20. Biotransformation of fluorophenyl pyridine carboxylic acids by the model fungus Cunninghamella elegans.

    Science.gov (United States)

    Palmer-Brown, William; Dunne, Brian; Ortin, Yannick; Fox, Mark A; Sandford, Graham; Murphy, Cormac D

    2017-09-01

    1. Fluorine plays a key role in the design of new drugs and recent FDA approvals included two fluorinated drugs, tedizolid phosphate and vorapaxar, both of which contain the fluorophenyl pyridyl moiety. 2. To investigate the likely phase-I (oxidative) metabolic fate of this group, various fluorinated phenyl pyridine carboxylic acids were incubated with the fungus Cunninghamella elegans, which is an established model of mammalian drug metabolism. 3.  19 F NMR spectroscopy established the degree of biotransformation, which varied depending on the position of fluorine substitution, and gas chromatography-mass spectrometry (GC-MS) identified alcohols and hydroxylated carboxylic acids as metabolites. The hydroxylated metabolites were further structurally characterised by nuclear magnetic resonance spectroscopy (NMR), which demonstrated that hydroxylation occurred on the 4' position; fluorine in that position blocked the hydroxylation. 4. The fluorophenyl pyridine carboxylic acids were not biotransformed by rat liver microsomes and this was a consequence of inhibitory action, and thus, the fungal model was crucial in obtaining metabolites to establish the mechanism of catabolism.

  1. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    Science.gov (United States)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  2. Determination of tetrahydrophtalimide and 2-thiothiazolidine-4-carboxylic acid, urinary metabolites of the fungicide captan, in rats and humans

    NARCIS (Netherlands)

    van Welie, R.T.H.; van Duyn, P; Lamme, E K; Jäger, P; van Baar, B L; Vermeulen, N P

    1991-01-01

    Capillary gas chromatographic (GC) methods using sulphur and mass selective detection for the qualitative and quantitative determination of tetrahydrophtalimide (THPI) and 2-thiothiazolidine-4-carboxylic acid (TTCA), urinary metabolites of the fungicide captan in rat and humans, were developed.

  3. In Vitro Reactivity of Carboxylic Acid-CoA Thioesters with Glutathione

    DEFF Research Database (Denmark)

    Sidenius, Ulrik; Skonberg, Christian; Olsen, Jørgen

    2004-01-01

    was to investigate whether a correlation could be found between the structure of acyl-CoA thioesters and their reactivities toward the tripeptide, glutathione (ç- Glu-Cys-Gly).  The  acyl-CoA  thioesters  of  eight  carboxylic  acids  (ibuprofen,  clofibric  acid, indomethacin,  fenbufen,  tolmetin,  salicylic  acid......The chemical reactivity of acyl-CoA thioesters toward nucleophiles has been demonstrated in several recent studies. Thus, intracellularly formed acyl-CoAs of xenobiotic carboxylic acids may react covalently with endogenous proteins and potentially lead to adverse effects. The purpose of this study......,  2-phenoxypropionic  acid,  and  (4-chloro-2-methyl-phenoxy)acetic  acid  (MCPA))  were  synthesized,  and  each  acyl-CoA  (0.5  mM)  was incubated with glutathione (5.0 mM) in 0.1 M potassium phosphate (pH 7.4, 37 °C). All of the acyl-CoAs reacted with glutathione to form the respective acyl...

  4. Mechanism of catalytic action of oxide systems in reactions of aldehyde oxidation to carboxylic acids

    International Nuclear Information System (INIS)

    Andrushkevich, T.V.

    1997-01-01

    Mechanism of selective action of oxide catalysts (on the base of V 2 O 4 , MoO 3 ) of aldehyde oxidation to acids is considered, reaction acrolein oxidation to acrylic acid is taken as an example. Multistage mechanism of the process is established; it involves consequent transformation of coordination-bonded aldehyde into carbonyl-bonded aldehyde and symmetric carboxylate. Principles of active surface construction are formulated, they take into account the activity of stabilization center of concrete intermediate compound and bond energy of oxygen with surface. (author)

  5. Chemistry of formation and properties of sapropelitic coals. III. Extraction of aliphatic carboxylic acids and ketones of normal structure

    Energy Technology Data Exchange (ETDEWEB)

    Bodoev, N.V.; Rokosov, Y.V.; Koptyug, V.A.

    1989-05-01

    Aliphatic carboxylic acids and ketones of normal structure produced in high yields by the reaction of Taimylyr boghead or Matagan gagat with water and sodium hydroxide at elevated pressure and at temperatures from 400 to 450 degrees C have been investigated. The compositions of these compounds have been studied by IRS, NMR and chromato-mass-spectrometry. The possible ways of formation of aliphatic carboxylic acids and ketones during the fossilization process have been discussed. 14 refs., 6 figs.

  6. Access to Alkyl-Substituted Lactone via Photoredox-Catalyzed Alkylation/Lactonization of Unsaturated Carboxylic Acids.

    Science.gov (United States)

    Sha, Wanxing; Ni, Shengyang; Han, Jianlin; Pan, Yi

    2017-11-03

    An efficient photoredox-catalyzed alkylation/lactonization reaction of unsaturated carboxylic acids by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. Varieties of redox-active esters derived from aliphatic carboxylic acids were proved viable in this method, affording alkyl substituted lactones in moderate to good yields. This redox-neutral procedure features mild conditions and operational simplicity, which provides a new strategy for the synthesis of alkyl substituted lactones.

  7. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Rupashree Shyama

    2009-02-10

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO{sub 2}{sup 2+}, [UO{sub 2}OH]{sup +}, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  8. Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

    International Nuclear Information System (INIS)

    Zargarian, S. Sh.; Haddadi-Asl, V.; Hematpour, H.

    2015-01-01

    Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite

  9. Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

    Energy Technology Data Exchange (ETDEWEB)

    Zargarian, S. Sh.; Haddadi-Asl, V., E-mail: haddadi@aut.ac.ir; Hematpour, H. [Amirkabir University of Technology, Department of Polymer Engineering and Color Technology (Iran, Islamic Republic of)

    2015-05-15

    Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite.

  10. Copper coordination polymers constructed from thiazole-5-carboxylic acid: Synthesis, crystal structures, and structural transformation

    Energy Technology Data Exchange (ETDEWEB)

    Meundaeng, Natthaya; Rujiwatra, Apinpus [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prior, Timothy J., E-mail: t.prior@hull.ac.uk [Chemistry, University of Hull, Kingston upon Hull HU6 7RX (United Kingdom)

    2017-01-15

    We have successfully prepared crystals of thiazole-5-carboxylic acid (5-Htza) (L) and three new thiazole-5-carboxylate-based Cu{sup 2+} coordination polymers with different dimensionality, namely, 1D [Cu{sub 2}(5-tza){sub 2}(1,10-phenanthroline){sub 2}(NO{sub 3}){sub 2}] (1), 2D [Cu(5-tza){sub 2}(MeOH){sub 2}] (2), and 3D [Cu(5-tza){sub 2}]·H{sub 2}O (3). These have been characterized by single crystal X-ray diffraction and thermogravimetry. Interestingly, the 2D network structure of 2 can directly transform into the 3D framework of 3 upon removal of methanol molecules at room temperature. 2 can also undergo structural transformation to produce the same 2D network present in the known [Cu(5-tza){sub 2}]·1.5H{sub 2}O upon heat treatment for 2 h. This 2D network can adsorb water and convert to 3 upon exposure to air. - Highlights: • Rare examples of coordination polymers of thiazole-5-carboxylic acid were prepared. • Non-covalent interactions play a key role on the assembly of the complexes in solid state. • Structural transformation of a 2D framework to a 3D upon removal of methanol is observed.

  11. Carboxylic acids at the surface of comet 67P/CG?

    Science.gov (United States)

    Istiqomah, I.; Quirico, E.; Faure, A.; Theulé, P.; Poch, O.; Beck, P.; Bonal, L.; Schmitt, B.; Ciarniello, M.; Filacchione, G.; Capaccioni, F.

    2017-09-01

    A broad feature centered at 3.2 μm has been detected in the reflectance spectra of comet 67P/Churyumov-Gerasimenko collected by the VIRTIS/Rosetta imaging spectrometer. This band points to the presence of semi-volatile organics, however to date no firm identification of molecular species has been done. In this study, we have focused on the experimental spectral characterization of carboxylic acids, which have been proposed as candidates for the 3.2 μm broad band. We show that simple carboxylic acids are not viable candidates, because of their thermal stability in regard to the surface temperature, and/or due the shape/size of their 3 μm band that does not fit VIRTIS spectra. We infer that if carboxyl groups are the main carrier of the 3.2 μm band, it should be present in a low mass macromolecule, along with OH groups in side chains that favor hydrogen bond. A balance ratio between OH groups and aliphatics CH2/CH3 must also be respected. Last, intimate mixtures do not fit VIRTIS data, and small spots of semi-volatiles on the surface of opaque material must be considered to account for 3.2 μm band.

  12. Selective Oxidation of 1,2-Propanediol to Carboxylic Acids Catalyzed by Copper Nanoparticles.

    Science.gov (United States)

    Xue, Wuping; Yin, Hengbo; Lu, Zhipeng; Wang, Aili; Liu, Shuxin; Shen, Lingqin

    2018-05-01

    Copper nanoparticles with different particle sizes were prepared by a wet chemical reduction method in the presence of organic modifiers, such as citric acid (CA), hexadecyl trimethyl ammonium bromide, Tween-80 (Tween), and polyethylene glycol 6000. Selective oxidation of sustainable 1,2-propanediol with O2 to high-valued lactic, formic, and acetic acids catalyzed by the copper nanoparticles in an alkaline medium was investigated. The small-sized CuCA nanoparticles with the average particle size of 15.2 nm favored the formation of acetic and formic acids while the CuTween nanoparticles with the average particle size of 26.9 nm were beneficial to the formation of lactic acid. The size effect of copper nanoparticles on the catalytic oxidation of 1,2-propanediol to the carboxylic acids was obvious.

  13. Alkenyl Carboxylic Acid: Engineering the Nanomorphology in Polymer-Polymer Solar Cells as Solvent Additive.

    Science.gov (United States)

    Zhang, Yannan; Yuan, Jianyu; Sun, Jianxia; Ding, Guanqun; Han, Lu; Ling, Xufeng; Ma, Wanli

    2017-04-19

    We have investigated a series of commercially available alkenyl carboxylic acids with different alkenyl chain lengths (trans-2-hexenoic acid (CA-6), trans-2-decenoic acid (CA-10), 9-tetradecenoic acid (CA-14)) for use as solvent additives in polymer-polymer non-fullerene solar cells. We systematically investigated their effect on the film absorption, morphology, carrier generation, transport, and recombination in all-polymer solar cells. We revealed that these additives have a significant impact on the aggregation of polymer acceptor, leading to improved phase segregation in the blend film. This in-depth understanding of the additives effect on the nanomorphology in all-polymer solar cell can help further boost the device performance. By using CA-10 with the optimal alkenyl chain length, we achieved fine phase separation, balanced charge transport, and suppressed recombination in all-polymer solar cells. As a result, an optimal power conversion efficiency (PCE) of 5.71% was demonstrated which is over 50% higher than that of the as-cast device (PCE = 3.71%) and slightly higher than that of devices with DIO treatment (PCE = 5.68%). Compared with widely used DIO, these halogen-free alkenyl carboxylic acids have a more sustainable processing as well as better performance, which may make them more promising candidates for use as processing additives in organic non-fullerene solar cells.

  14. A comprehensive evaluation of the toxicology of cigarette ingredients: aliphatic and aromatic carboxylic acids.

    Science.gov (United States)

    Coggins, Christopher R E; Liu, Jianmin; Merski, Jerome A; Werley, Michael S; Oldham, Michael J

    2011-06-01

    Aromatic and aliphatic carboxylic acids are present in tobacco and tobacco smoke. A battery of tests was used to compare the toxicity of mainstream smoke from experimental cigarettes containing eight aromatic and aliphatic carboxylic acids and the salt of one acid that were added individually at three different levels (lowest and highest target inclusions were 100 and 90,000 ppm, respectively). Mainstream smoke from cigarettes containing each of the test ingredients was evaluated using analytical chemistry and assays to measure in vitro cytotoxicity (neutral red uptake) and Salmonella (five strains) mutagenicity. For four of the compounds (citric, lactic, benzoic acids, and sodium benzoate), 90-day rodent inhalation studies were also performed. Although sporadic statistically significant differences in some experimental cigarette smoke constituents occurred, none resulted in significant changes in mutagenicity or cytotoxicity responses, nor in responses measured in the inhalation studies, except for lactic acid (LA). Inclusion of LA resulted in dose-dependent increase in water and caused a dose-dependent decrease in cytotoxicity. Incorporation of LA into cigarettes resulted in several dose-related reductions in histopathology, which were largely restricted to the nasal passages. Incorporation of LA also ameliorated some of the typical decrease in body weight gain seen in cigarette smoke-exposed rats. Inclusion of these ingredients at exaggerated use levels resulted in sporadic dose-related and treatment effects for some smoke constituents, but no toxicological response was noted in the in vitro and in vivo tests performed.

  15. Recovery of carboxylic acids at pH greater than pKa

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Lisa A. [Univ. of California, Berkeley, CA (United States)

    1993-08-01

    Economics of producing carboxylic acids by fermentation is often dominated, not by the fermentation cost, but by the cost of recovering and purifying the acids from dilute aqueous solutions. Experiments were performed to measure uptakes of lactic and succinic acids as functions of pH by basic polymeric sorbents; sorbent regeneration was also tested. Performance at pH > pKa and regenerability depend on sorbent basicity; apparent pKa and monomer pK{sub a} can be used to predict sorbent performance. Two basic amine extractants, Alamine 336 and Amberlite LA-2, in were also studied; they are able to sustain capacity to higher pH in diluents that stabilize the acid-amine complex through H bonding. Secondary amines perform better than tert-amines in diluents that solvate the additional proton. Competitive sulfate and phosphate, an interference in fermentation, are taken up by sorbents more strongly than by extractants. The third step in the proposed fermentation process, the cracking of the trimethylammonium (TMA) carboxylate, was also examined. Because lactic acid is more soluble and tends to self-esterify, simple thermal cracking does not remove all TMA; a more promising approach is to esterify the TMA lactate by reaction with an alcohol.

  16. Can an amine be a stronger acid than a carboxylic acid? The surprisingly high acidity of amine-borane complexes.

    Science.gov (United States)

    Martín-Sómer, Ana; Lamsabhi, Al Mokhtar; Yáñez, Manuel; Dávalos, Juan Z; González, Javier; Ramos, Rocío; Guillemin, Jean-Claude

    2012-12-03

    The gas-phase acidity of a series of amine-borane complexes has been investigated through the use of electrospray mass spectrometry (ESI-MS), with the application of the extended Cooks kinetic method, and high-level G4 ab initio calculations. The most significant finding is that typical nitrogen bases, such as aniline, react with BH(3) to give amine-borane complexes, which, in the gas phase, have acidities as high as those of either phosphoric, oxalic, or salicylic acid; their acidity is higher than many carboxylic acids, such as formic, acetic, and propanoic acid. Indeed the complexation of different amines with BH(3) leads to a substantial increase (from 167 to 195 kJ mol(-1)) in the intrinsic acidity of the system; in terms of ionization constants, this increase implies an increase as large as fifteen orders of magnitude. Interestingly, this increase in acidity is almost twice as large as that observed for the corresponding phosphine-borane analogues. The agreement between the experimental and the G4-based calculated values is excellent. The analysis of the electron-density rearrangements of the amine and the borane moieties indicates that the dative bond is significantly stronger in the N-deprotonated anion than in the corresponding neutral amine-borane complex, because the deprotonated amine is a much better electron donor than the neutral amine. On the top of that, the newly created lone pair on the nitrogen atom in the deprotonated species, conjugates with the BN bonding pair. The dispersion of the extra electron density into the BH(3) group also contributes to the increased stability of the deprotonated species. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Gas-Phase Partial Oxidation of Lignin to Carboxylic Acids over Vanadium Pyrophosphate and Aluminum-Vanadium-Molybdenum.

    Science.gov (United States)

    Lotfi, Samira; Boffito, Daria C; Patience, Gregory S

    2015-10-26

    Lignin is a complex polymer that is a potential feedstock for aromatic compounds and carboxylic acids by cleaving the β-O-4 and 5-5' linkages. In this work, a syringe pump atomizes an alkaline solution of lignin into a catalytic fluidized bed operating above 600 K. The vanadium heterogeneous catalysts convert all the lignin into carboxylic acids (up to 25 % selectivity), coke, carbon oxides, and hydrogen. Aluminum-vanadium-molybdenum mostly produced lactic acid (together with formic acid, acrylic acid, and maleic anhydride), whereas the vanadium pyrophosphate catalyst produced more maleic anhydride. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of carboxylic acids as compatibilizer agent on mechanical properties of thermoplastic starch and polypropylene blends.

    Science.gov (United States)

    Martins, Andréa Bercini; Santana, Ruth Marlene Campomanes

    2016-01-01

    In this work, polypropylene/thermoplastic starch (PP/TPS) blends were prepared as an alternative material to use in disposable packaging, reducing the negative polymeric environmental impact. Unfortunately, this material displays morphological characteristics typical of immiscible polymer blends and a compatibilizer agent is needed. Three different carboxyl acids: myristic (C14), palmitic (C16) and stearic acids (C18) were used as natural compatibilizer agent (NCA). The effects of NCA on the mechanical, physical, thermal and morphological properties of PP/TPS blends were investigated and compared against PP/TPS with and without PP-grafted maleic anhydride (PPgMA). When compared to PP/TPS, blends with C18, PPgMA and C14 presented an improvement of 25, 22 and 17% in tensile strength at break and of 180, 194 and 259% in elongation at break, respectively. The highest increase, 54%, in the impact strength was achieved with C14 incorporation. Improvements could be seen, through scanning electron microscopy (SEM) images, in the compatibility between the immiscible components by acids incorporation. These results showed that carboxylic acids, specifically C14, could be used as compatibilizer agent and could substitute PPgMA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Effect of Alkyl Chain Length on Carboxylic Acid SAMs on Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    Gavin A. Buckholtz

    2012-07-01

    Full Text Available The formation of methyl-terminated carboxylic acid self-assembled monolayers (SAMs with even numbers of carbons, from eighteen to thirty, was investigated on the oxide surface of Ti-6Al-4V and component metal oxides. Modified surfaces were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS and contact angle analysis. Infrared spectroscopy indicated that using aerosol spray deposition techniques, stable, all-trans SAMs of octacosanoic (28 carbons and triacontanoic (30 carbons acids were formed on the alloy. Films were similarly formed on titanium and aluminum oxide. The surface of vanadium oxide exhibited limited reactivity. MALDI-TOF MS confirmed that formed films were monolayers, without multilayers or aggregates present. Water contact angles are indicative of the presence of hydrophobic methyl groups at the interface. This stable carboxylic acid SAM formation could be a useful alternative to phosphonic acid SAMs for corrosion and other applications.

  20. Kinetic analysis of the reactivity of aliphatic cyclic alcohols and carboxylic acids in the T-for-H exchange reaction

    International Nuclear Information System (INIS)

    Tamura, Kiyoshi; Imaizumi, Hiroshi; Kano, Naoki

    2007-01-01

    In order to quantitatively evaluate the influence of tritium ( 3 He or T) on various functional groups in environment, the hydrogen isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly-(vinyl alcohol) and each aliphatic cyclic alcohol (or carboxylic acid) has been dynamically observed in the range of 50 to 90degC. Consequently, the activities of the aliphatic cyclic alcohol and carboxylic acid increased with increasing reaction time. Applying in A''-McKay plot method to the observed data, the rate constants (k) for these materials were obtained. Using the k, the relation between the number of carbon atoms in the ring in each alcohol and the reactivity of the alcohol was quantitatively compared. Then, to clarify the effect of relative atomic charge of O atom (connected with the H atom in the hydroxy (or carboxy) group in the material) on the reactivity of the material, the MOPAC method was used. From both the above-mentioned and the obtained previously, the following nine items were found as to aliphatic cyclic alcohols (and carboxylic acids) in the T-for-H exchange reaction. (1) The reactivity of aliphatic cyclic alcohols (and carboxylic acids) depends on the temperature. (2) The reactivity of the cyclic materials decreases with increasing number of carbon atoms in the ring. (3) The reactivity of the aliphatic cyclic carboxylic acid seems to be smaller than that of aliphatic cyclic alcohol, and be larger than that of aliphatic cyclic amine. (4) For aliphatic cyclic alcohols, correlation exists between k and relative atomic charges of O atom obtained by the MOPAC method, but the tendency for aliphatic cyclic carboxylic acid is not clear. (5) As to having the same number of carbon atoms in each ring, the reactivity of the aliphatic cyclic carboxylic acid including the side chain is smaller than of the aliphatic cyclic carboxylic acid including no side chain. (6) The reactivity of aliphatic cyclic carboxylic acid is larger than that of

  1. Evaluation of toxic effects of several carboxylic acids on bacterial growth by toxicodynamic modelling

    Directory of Open Access Journals (Sweden)

    Vázquez José

    2011-11-01

    Full Text Available Abstract Background Effects of organic acids on microbial fermentation are commonly tested in investigations about metabolic behaviour of bacteria. However, they typically provide only descriptive information without modelling the influence of acid concentrations on bacterial kinetics. Results We developed and applied a mathematical model (secondary model to capture the toxicological effects of those chemicals on kinetic parameters that define the growth of bacteria in batch cultures. Thus, dose-response kinetics were performed with different bacteria (Leuconostoc mesenteroides, Carnobacterium pisicola, Escherichia coli, Bacillus subtilis and Listonella anguillarum exposed at increasing concentrations of individual carboxylic acids (formic, acetic, propionic, butyric and lactic. In all bioassays the acids affected the maximum bacterial load (Xm and the maximum growth rate (vm but only in specific cases the lag phase (λ was modified. Significance of the parameters was always high and in all fermentations the toxicodynamic equation was statistically consistent and had good predictability. The differences between D and L-lactic acid effects were significant for the growth of E. coli, L. mesenteroides and C. piscicola. In addition, a global parameter (EC50,τ was used to compare toxic effects and provided a realistic characterization of antimicrobial agents using a single value. Conclusions The effect of several organic acids on the growth of different bacteria was accurately studied and perfectly characterized by a bivariate equation which combines the basis of dose-response theory with microbial growth kinetics (secondary model. The toxicity of carboxylic acids was lower with the increase of the molecular weight of these chemicals.

  2. Towards modelling the vibrational signatures of functionalized surfaces: carboxylic acids on H-Si(111) surfaces

    Science.gov (United States)

    Giresse Tetsassi Feugmo, Conrard; Champagne, Benoît; Caudano, Yves; Cecchet, Francesca; Chabal, Yves J.; Liégeois, Vincent

    2012-03-01

    In this work, we investigate the adsorption process of two carboxylic acids (stearic and undecylenic) on a H-Si(111) surface via the calculation of structural and energy changes as well as the simulation of their IR and Raman spectra. The two molecules adsorb differently at the surface since the stearic acid simply physisorbs while the undecylenic acid undergoes a chemical reaction with the hydrogen atoms of the surface. This difference is observed in the change of geometry during the adsorption. Indeed, the chemisorption of the undecylenic acid has a bigger impact on the structure than the physisorption of the stearic acid. Consistently, the former is also characterized by a larger value of adsorption energy and a smaller value of the tilting angle with respect to the normal plane. For both the IR and Raman signatures, the spectra of both molecules adsorbed at the surface are in a first approximation the superposition of the spectra of the Si cluster and of the carboxylic acid considered individually. The main deviation from this simple observation is the peak of the stretching Si-H (ν(Si-H)) mode, which is split into two peaks upon adsorption. As expected, the splitting is bigger for the chemisorption than the physisorption. The modes corresponding to atomic displacements close to the adsorption site display a frequency upshift by a dozen wavenumbers. One can also see the disappearance of the peaks associated with the C=C double bond when the undecylenic acid chemisorbs at the surface. The Raman and IR spectra are complementary and one can observe here that the most active Raman modes are generally IR inactive. Two exceptions to this are the two ν(Si-H) modes which are active in both spectroscopies. Finally, we compare our simulated spectra with some experimental measurements and we find an overall good agreement.

  3. Towards modelling the vibrational signatures of functionalized surfaces: carboxylic acids on H-Si(111) surfaces

    International Nuclear Information System (INIS)

    Tetsassi Feugmo, Conrard Giresse; Champagne, Benoît; Liégeois, Vincent; Caudano, Yves; Cecchet, Francesca; Chabal, Yves J

    2012-01-01

    In this work, we investigate the adsorption process of two carboxylic acids (stearic and undecylenic) on a H-Si(111) surface via the calculation of structural and energy changes as well as the simulation of their IR and Raman spectra. The two molecules adsorb differently at the surface since the stearic acid simply physisorbs while the undecylenic acid undergoes a chemical reaction with the hydrogen atoms of the surface. This difference is observed in the change of geometry during the adsorption. Indeed, the chemisorption of the undecylenic acid has a bigger impact on the structure than the physisorption of the stearic acid. Consistently, the former is also characterized by a larger value of adsorption energy and a smaller value of the tilting angle with respect to the normal plane. For both the IR and Raman signatures, the spectra of both molecules adsorbed at the surface are in a first approximation the superposition of the spectra of the Si cluster and of the carboxylic acid considered individually. The main deviation from this simple observation is the peak of the stretching Si-H (ν(Si-H)) mode, which is split into two peaks upon adsorption. As expected, the splitting is bigger for the chemisorption than the physisorption. The modes corresponding to atomic displacements close to the adsorption site display a frequency upshift by a dozen wavenumbers. One can also see the disappearance of the peaks associated with the C=C double bond when the undecylenic acid chemisorbs at the surface. The Raman and IR spectra are complementary and one can observe here that the most active Raman modes are generally IR inactive. Two exceptions to this are the two ν(Si-H) modes which are active in both spectroscopies. Finally, we compare our simulated spectra with some experimental measurements and we find an overall good agreement. (paper)

  4. Biological roles and therapeutic potential of hydroxy-carboxylic acid receptors

    Directory of Open Access Journals (Sweden)

    Kashan eAhmed

    2011-10-01

    Full Text Available In the recent past, deorphanization studies have described intermediates of energy metabolism to activate G protein-coupled receptors (GPCRs and to thereby regulate metabolic functions. GPR81, GPR109A and GPR109B, formerly known as the nicotinic acid receptor family, are encoded by clustered genes and share a high degree of sequence homology. Recently, hydroxy-carboxylic acids were identified as endogenous ligands of GPR81, GPR109A and GPR109B, and therefore these receptors have been placed into a novel receptor family of hydroxy-carboxylic acid (HCA receptors. The HCA1 receptor (GPR81 is activated by the glycolytic metabolite 2-hydroxy-propionic acid (lactate, the HCA2 receptor is activated by the ketone body 3-hydroxy-butyric acid and the HCA3 receptor (GPR109B is a receptor for the β-oxidation intermediate 3-hydroxy-octanoic acid. While HCA1 and HCA2 receptors are present in most mammalian species, the HCA3 receptor is exclusively found in humans and higher primates. HCA receptors are expressed in adipose tissue and mediate anti-lipolytic effects in adipocytes through Gi-type G-protein-dependent inhibition of adenylyl cyclase. HCA2 and HCA3 inhibit lipolysis during conditions of increased β-oxidation such as prolonged fasting, whereas HCA1 mediates the anti-lipolytic effects of insulin in the fed state. As HCA2 is a receptor for the established anti-dyslipidemic drug nicotinic acid, HCA1 and HCA3 also represent promising drug targets and several synthetic ligands for HCA receptors have been developed. In this article, we will summarize the deorphanization and pharmacological characterization of HCA receptors. Moreover, we will discuss recent progress in elucidating the physiological and pathophysiological role to further evaluate the therapeutic potential of the HCA receptor family for the treatment of metabolic disease.

  5. Highly Efficient Sulfonic/Carboxylic Dual-Acid Synergistic Catalysis for Esterification Enabled by Sulfur-Rich Graphene Oxide.

    Science.gov (United States)

    Zhang, Honglei; Luo, Xiang; Shi, Kaiqi; Wu, Tao; He, Feng; Zhou, Shoubin; Chen, George Z; Peng, Chuang

    2017-09-11

    A new sulfonic/carboxylic dual-acid catalyst based on sulfur-rich graphene oxide (GO-S) was readily prepared and used as a highly efficient and reusable solid acid catalyst toward the esterification of oleic acid with methanol for biodiesel production. Higher yields of methyl oleate (98 %) and over 3 times higher turnover frequencies (TOFs) were observed for the GO-S dual-acid catalyst, compared to liquid sulfuric acid or other carbon-based solid acid catalysts. The "acidity" of sulfonic acid groups was enhanced by the addition of carboxylic acid groups as the combination of the two acids enhances their inherent activity by associative interaction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids.

    Science.gov (United States)

    Fu, Ming-Chen; Shang, Rui; Cheng, Wan-Min; Fu, Yao

    2015-07-27

    A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Unusual Regioselectivity in the Opening of Epoxides by Carboxylic Acid Enediolates

    Directory of Open Access Journals (Sweden)

    José Segura

    2008-06-01

    Full Text Available Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpectedly, to a mixture resulting from the attack on both the primary and secondary carbon atoms. Generally, a low diastereoselectivity is seen on attack at the primary center, however only one diastereoisomer was obtained from attack to the secondary carbon of the styrene oxide.

  8. Multifunctional Aromatic Carboxylic Acids as Versatile Building Blocks for Hydrothermal Design of Coordination Polymers

    Directory of Open Access Journals (Sweden)

    Jinzhong Gu

    2018-02-01

    Full Text Available Selected recent examples of coordination polymers (CPs or metal-organic frameworks (MOFs constructed from different multifunctional carboxylic acids with phenyl-pyridine or biphenyl cores have been discussed. Despite being still little explored in crystal engineering research, such types of semi-rigid, thermally stable, multifunctional and versatile carboxylic acid building blocks have become very promising toward the hydrothermal synthesis of metal-organic architectures possessing distinct structural features, topologies, and functional properties. Thus, the main aim of this mini-review has been to motivate further research toward the synthesis and application of coordination polymers assembled from polycarboxylic acids with phenyl-pyridine or biphenyl cores. The importance of different reaction parameters and hydrothermal conditions on the generation and structural types of CPs or MOFs has also been highlighted. The influence of the type of main di- or tricarboxylate ligand, nature of metal node, stoichiometry and molar ratio of reagents, temperature, and presence of auxiliary ligands or templates has been showcased. Selected examples of highly porous or luminescent CPs, compounds with unusual magnetic properties, and frameworks for selective sensing applications have been described.

  9. Omega-3 carboxylic acids monotherapy and combination with statins in the management of dyslipidemia

    Directory of Open Access Journals (Sweden)

    Benes LB

    2016-12-01

    Full Text Available Lane B Benes1, Nikhil S Bassi2, Michael H Davidson1 1Department of Medicine, Section of Cardiology, 2Department of Medicine, University of Chicago, Chicago, IL, USA Abstract: The 2013 American College of Cardiology/American Heart Association guidelines on cholesterol management placed greater emphasis on statin therapy given the well-established benefits in primary and secondary prevention of cardiovascular disease. Residual risk may remain after statin initiation, in part because of triglyceride-rich lipoprotein cholesterol. Several large trials have failed to show benefit with non-statin cholesterol-lowering medications in the reduction of cardiovascular events. Yet, subgroup analyses showed a benefit in those with hypertriglyceridemia and lower high-density lipoprotein cholesterol level, a high-risk pattern of dyslipidemia. This review discusses the benefits of omega-3 carboxylic acids, a recently approved formulation of omega-3 fatty acid with enhanced bioavailability, in the treatment of dyslipidemia both as monotherapy and combination therapy with a statin. Keywords: omega-3 carboxylic acids, non-HDL-C, hypertriglyceridemia, residual risk, statin

  10. Kinetic studies on the carboxylation of 6-amino-penicillanic acid to 8-hydroxy-penillic acid

    DEFF Research Database (Denmark)

    Henriksen, Claus Maxel; Holm, SS; Schipper, D.

    1997-01-01

    The carboxylation in aqueous solution of 6-amino-penicillanic acid (6-APA) to 8-hydroxy-penillic acid (8-HPA) was studied at 25 degrees C and pH 6.5. During sparging with either a citrate buffer or a chemically defined cultivation medium containing 6-APA with mixtures of carbon dioxide and air (2.......7-41% (v/v) CO2), the kinetics for conversion of 6-APA was followed by HPLC. In the citrate buffer 6-APA was converted by two competitive reactions each following first order kinetics with respect to the concentration of 6-APA: 1. carboxylation into 8-HPA; and 2. slow conversion into an unknown compound....... Formation of the unknown compound was not observed in the cultivation medium. The carboxylation of 6-APA was also found to be first order with respect to the concentration of dissolved carbon dioxide. The rate constant for formation of 8-HPA did not differ significantly in the cultivation medium compared...

  11. Investigations of the reactivity of pyridine carboxylic acids with diazodiphenylmethane in protic and aprotic solvents.

    Directory of Open Access Journals (Sweden)

    ALEKSANDAR D. MARINKOVIC

    2005-04-01

    Full Text Available Rate constants for the reaction of diazodiphenylmethane with isomeric pyridine carboxylic acids were determined in chosen protic and aprotic solvents at 30 °C, using the well known UV spectrophotometric method. The values of the rate constants of the investigated acids in protic solvents were higher than those in aprotic solvents. The second order rate constants were correlated with solvent parameters using the Kamlet-Taft solvatochromic equation in the form: log k = log k0 + sp* + aa + bb . The correlation of the obtained kinetic data were performed by means of multiple linear regression analysis taking appropriate solvent parameters. The signs of the equation coefficients were in agreement with the postulated reaction mechanism. The mode of the influence of the solvent on the reaction rate in all the investigated acids are discussed on the basis of the correlation results.

  12. Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

    Directory of Open Access Journals (Sweden)

    Elizabeth I. Braun

    2016-06-01

    Full Text Available It is well known that surfactant-suspended carbon nanotube (CNT samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ∼40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.

  13. Extraction of lanthanide(III) and yttrium(III) nitrates by trialkylbenzylammonium carboxylates (fragments of higher isomers of α,α'-branched carboxylic acids) in toluene

    International Nuclear Information System (INIS)

    Pyartman, A.K.; Kopyrin, A.A.; Zhikharev, D.A.; Keskinov, V.A.

    2003-01-01

    Extraction of lanthanide(III) [La-Lu(III)] and yttrium nitrates by trialkylbenzylammonium carboxylates [fragments of higher isomers of α,α'-branched carboxylic acids (A)] in toluene at 298 K is investigated. Extraction isotherms are described taking into account formation of compounds of (R 4 N) 2 [Ln(NO 3 ) 3 A 2 ] and (R 4 N) 3 [Ln(NO 3 ) 3 A 3 ] composition in organic phase. Values of extraction constants that decrease in La(Ce)(III)-Lu(III) row are calculated. Values of extraction constants for Y(III) are lower than for lanthanides(III). IR spectra of the compounds in organic phase are studied [ru

  14. Electrochemical analysis of the adsorption and desorption behaviors of carboxylic acid and anhydride monomers onto zinc surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, P. [Materials innovation institute (M2i), Mekelweg 2, 2628 CD Delft (Netherlands); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Hauffman, T. [Vrije Universiteit Brussel, Department of Electrochemical and Surface Engineering, Pleinlaan 2, B-1050 Brussels (Belgium); Mol, J.M.C. [Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Flores, J.R.; Hannour, F. [Tata Steel Research, Development and Technology, PO Box 10.000, 1970 CA IJmuiden (Netherlands); Wit, J.H.W. de [Materials innovation institute (M2i), Mekelweg 2, 2628 CD Delft (Netherlands); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Terryn, H., E-mail: hterryn@irexchange.vub.ac.b [Materials innovation institute (M2i), Mekelweg 2, 2628 CD Delft (Netherlands); Vrije Universiteit Brussel, Department of Electrochemical and Surface Engineering, Pleinlaan 2, B-1050 Brussels (Belgium)

    2011-10-30

    The interfacial bondings formed between succinic acid and myristic acid, as well as succinic anhydride molecules with a set of differently treated zinc substrates have been investigated using infrared reflection absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The compounds were selected to model typically used carboxylic-based adhesives and coatings. Moreover, the adsorption kinetic has been evaluated by means of chronoamperometry (CA) and chronovoltammetry measurements. XPS results showed a relation between the amount of carboxylates formed by adsorption of succinic acid/myristic acid and the hydroxyl fraction presented on the surfaces as proved by a higher electron transfer in CA. On the other hand a set of oxidative/reductive interactions was detected during the adsorption of succinic anhydride, in turn proving a spontaneous ring opening and adsorption mechanism. A clear relationship between the amount of adsorbents and surface hydroxyls/carbonates was detected for the adsorption of succinic anhydride. The extent to which the formed carboxylates resisted negative potentials was also investigated by cyclic voltammetry (CV) in an aqueous solution. The coordinative bonding of a bifunctional carboxylic acid group to the oxide surface was found to be not stable in the presence of a negative potential, while a monofunctional carboxylic acid group could resist displacement by water for a prolonged period of time. On the other hand, a low double layer capacitance was obtained after the adsorption of succinic anhydride, which was related to a change in potential of zero charge (PZC) upon the adsorption.

  15. Pd-catalysed ligand-enabled carboxylate-directed highly regioselective arylation of aliphatic acids

    Science.gov (United States)

    Zhu, Yan; Chen, Xiaolan; Yuan, Chunchen; Li, Guobao; Zhang, Jingyu; Zhao, Yingsheng

    2017-04-01

    α-amino acids bearing aromatic side chains are important synthetic units in the synthesis of peptides and natural products. Although various β-C-H arylation methodologies for amino acid derivatives involving the assistance of directing groups have been extensively developed, syntheses that directly employ N-protected amino acids as starting materials remain rare. Herein, we report an N-acetylglycine-enabled Pd-catalysed carboxylate-directed β-C(sp3)-H arylation of aliphatic acids. In this way, various non-natural amino acids can be directly prepared from phthaloylalanine in one step in good to excellent yields. Furthermore, a series of aliphatic acids have been shown to be amenable to this transformation, affording β-arylated propionic acid derivatives in moderate to good yields. More importantly, this ligand-enabled direct β-C(sp3)-H arylation could be easily scaled-up to 10 g under reflux conditions, highlighting the potential utility of this synthetic method.

  16. Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

    2003-05-16

    The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

  17. An acridinium sulphonylamide as a new chemiluminescent label for the determination of carboxylic acids in liquid chromatography

    NARCIS (Netherlands)

    Steijger, O.M.; Kamminga, D.A.; Lingeman, H.; Brinkman, U.A.T.

    1998-01-01

    The synthesis of a new acridinium sulphonylamide label for the liquid chromatographic determination of carboxylic acids is described. The label 10-methyl-N-(p-tolyl)-N-(p-iodoacetamidobenzenesulphonyl)-9-acridinium carboxamide iodide is synthesized from 9-acridinecarboxylic acid by a seven-step

  18. Selenium speciation in urine by ion-pairing chromatography with perfluorinated carboxylic acids and ICP-MS detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Bendahl, L.; Sidenius, U.

    2002-01-01

    Five aqueous standards, selenomethionine (SeMet), methylselenomethionine (MeSeMet), methylselenocysteine (MeSeCys), selenogammaaminobutyric acid (SeGaba) and the trimethylselenonium ion (TMSe), were separated in ion-pairing chromatographic systems based on perfluorinated carboxylic acids in metha...

  19. Theoretical evaluation of flotation performance of carboxyl hydroxamic acids with different number of polar groups on the surfaces of diaspore (010) and kaolinite (001).

    Science.gov (United States)

    Wang, Fang-ping; Zhan, Guo-ping; Jiang, Yu-ren; Guo, Jing-nan; Yin, Zhi-gang; Feng, Rui

    2013-08-01

    The adsorption behaviors of three carboxyl hydroxamic acids on diaspore (010) and kaolinite (001) have been studied by density functional theory (DFT) and molecular dynamics (MD) method. The results indicated that carboxyl hydroxamic acids could adsorb on diaspore surface by ionic bonds and hydrogen bonds, and adsorb on kaolinite surface by hydrogen bonds. The models of carboxyl hydroxamic acids adsorbed on diaspore and kaolinite surfaces are proposed.

  20. Conjugates of 1'-Aminoferrocene-1-carboxylic Acid and Proline: Synthesis, Conformational Analysis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Monika Kovačević

    2014-08-01

    Full Text Available Our previous studies showed that alteration of dipeptides Y-Fca-Ala-OMe (III into Y-Ala-Fca-OMe (IV (Y = Ac, Boc; Fca = 1'-aminoferrocene-1-carboxylic acid significantly influenced their conformational space. The novel bioconjugates Y-Fca-Pro-OMe (1, Y = Ac; 2, Y = Boc and Y-Pro-Fca-OMe (3, Y = Boc; 4, Y = Ac have been prepared in order to investigate the influence of proline, a well-known turn-inducer, on the conformational properties of small organometallic peptides with an exchanged constituent amino acid sequences. For this purpose, peptides 1–4 were subjected to detailed spectroscopic analysis (IR, NMR, CD spectroscopy in solution. The conformation of peptide 3 in the solid state was determined. Furthermore, the ability of the prepared conjugates to inhibit the growth of estrogen receptor-responsive MCF-7 mammary carcinoma cells and HeLa cervical carcinoma cells was tested.

  1. Electrochemical properties of polyolefine nonwoven fabric modified with carboxylic acid group for battery separator

    International Nuclear Information System (INIS)

    Choi, Seong-Ho; Park, Keung-Shik; Kang, Hae-Jeong; Ryu, Eun-Nyoung; Lee, Pill-Kwang

    2000-01-01

    Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto polyolefine nonwoven fabric (PNF), wherein the PNF comprises at least about 60% of a polyethylene having a melting temperature at ∼132degC and no more than about 40% of a second polypropylene having a lower melting temperature at ∼162degC, for a battery separator. The AAc-grafted PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The tensile strength decreased with increasing grafting yield, whereas the elongation decreased with increasing grafting yield. (author)

  2. Electrochemical properties of polyolefin nonwoven fabric modified with carboxylic acid group for battery separator

    International Nuclear Information System (INIS)

    Choi, Seong-Ho; Kang, Hae-Jeong; Ryu, Eun-Nyoung; Lee, Kwang-Pill

    2001-01-01

    Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto polyolefine nonwoven fabric (PNF), wherein the PNF comprises at least about 60% of a polyethylene having a melting temperature at ∼132 deg. C and no more than about 40% of a second polypropylene having a lower melting temperature at ∼162 deg. C, for a battery separator. The AAc-grafted PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The tensile strength decreased with increasing grafting yield, whereas the elongation decreased with increasing grafting yield. (author)

  3. Cu-catalyzed formal methylative and hydrogenative carboxylation of alkynes with carbon dioxide: efficient synthesis of α,β-unsaturated carboxylic acids.

    Science.gov (United States)

    Takimoto, Masanori; Hou, Zhaomin

    2013-08-19

    The sequential hydroalumination or methylalumination of various alkynes catalyzed by different catalyst systems, such those based on Sc, Zr, and Ni complexes, and the subsequent carboxylation of the resulting alkenylaluminum species with CO2 catalyzed by an N-heterocyclic carbene (NHC)-copper catalyst have been examined in detail. The regio- and stereoselectivity of the overall reaction relied largely on the hydroalumination or methylalumination reactions, which significantly depended on the catalyst and alkyne substrates. The subsequent Cu-catalyzed carboxylation proceeded with retention of the stereoconfiguration of the alkenylaluminum species. All the reactions could be carried out in one-pot to afford efficiently a variety of α,β-unsaturated carboxylic acids with well-controlled configurations, which are difficult to construct by previously reported methods. This protocol could be practically useful and attractive because of its high regio- and stereoselectivity, simple one-pot reaction operation, and the use of CO2 as a starting material. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Stereospecific synthesis of syn-α-oximinoamides by a three-component reaction of isocyanides, syn-chlorooximes, and carboxylic acids.

    Science.gov (United States)

    Pirali, Tracey; Mossetti, Riccardo; Galli, Simona; Tron, Gian Cesare

    2011-07-15

    A stereospecific multicomponent reaction among isocyanides, syn-chlorooximes, and carboxylic acids provides an efficient synthesis of biologically relevant syn-α-oximinoamides. © 2011 American Chemical Society

  5. Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

    2018-01-01

    Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

  6. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

    Directory of Open Access Journals (Sweden)

    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  7. Novel Isoniazid cocrystals with aromatic carboxylic acids: Crystal engineering, spectroscopy and thermochemical investigations

    Science.gov (United States)

    Diniz, Luan F.; Souza, Matheus S.; Carvalho, Paulo S.; da Silva, Cecilia C. P.; D'Vries, Richard F.; Ellena, Javier

    2018-02-01

    Four novel cocrystals of the anti-tuberculosis drug Isoniazid (INH), including two polymorphs, with the aromatic carboxylic acids p-nitrobenzoic (PNBA), p-cyanobenzoic (PCNBA) and p-aminobenzoic (PABA) were rationally designed and synthesized by solvent evaporation. Aiming to explore the possible supramolecular synthons of this API, these cocrystals were fully characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR) and thermal (TGA, DSC, HSM) techniques. The cocrystal formation was found to be mainly driven by the synthons formed by the pyridine and hydrazide moieties. In both INH-PABA polymorphs, the COOH acid groups are H-bonded to pyridine and hydrazide groups giving rise to the acid⋯pyridine and acid⋯hydrazide heterosynthons. In INH-PNBA and INH-PCNBA cocrystals these acid groups are only related to the pyridine moiety. In addition to the structural study, supramolecular and Hirshfeld surface analysis were also performed based on the structural data. The cocrystals were identified from the FT-IR spectra and their thermal behaviors were studied by a combination of DSC, TGA and HSM techniques.

  8. Anti-Inflammatory and Antinociceptive Activities of Anthraquinone-2-Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Jae Gwang Park

    2016-01-01

    Full Text Available Anthraquinone compounds are one of the abundant polyphenols found in fruits, vegetables, and herbs. However, the in vivo anti-inflammatory activity and molecular mechanisms of anthraquinones have not been fully elucidated. We investigated the activity of anthraquinones using acute inflammatory and nociceptive experimental conditions. Anthraquinone-2-carboxylic acid (9,10-dihydro-9,10-dioxo-2-anthracenecarboxylic acid, AQCA, one of the major anthraquinones identified from Brazilian taheebo, ameliorated various inflammatory and algesic symptoms in EtOH/HCl- and acetylsalicylic acid- (ASA- induced gastritis, arachidonic acid-induced edema, and acetic acid-induced abdominal writhing without displaying toxic profiles in body and organ weight, gastric irritation, or serum parameters. In addition, AQCA suppressed the expression of inflammatory genes such as cyclooxygenase- (COX- 2 in stomach tissues and lipopolysaccharide- (LPS- treated RAW264.7 cells. According to reporter gene assay and immunoblotting analyses, AQCA inhibited activation of the nuclear factor- (NF- κB and activator protein- (AP- 1 pathways by suppression of upstream signaling involving interleukin-1 receptor-associated kinase 4 (IRAK1, p38, Src, and spleen tyrosine kinase (Syk. Our data strongly suggest that anthraquinones such as AQCA act as potent anti-inflammatory and antinociceptive components in vivo, thus contributing to the immune regulatory role of fruits and herbs.

  9. Anti-Inflammatory and Antinociceptive Activities of Anthraquinone-2-Carboxylic Acid.

    Science.gov (United States)

    Park, Jae Gwang; Kim, Seung Cheol; Kim, Yun Hwan; Yang, Woo Seok; Kim, Yong; Hong, Sungyoul; Kim, Kyung-Hee; Yoo, Byong Chul; Kim, Shi Hyung; Kim, Jong-Hoon; Cho, Jae Youl

    2016-01-01

    Anthraquinone compounds are one of the abundant polyphenols found in fruits, vegetables, and herbs. However, the in vivo anti-inflammatory activity and molecular mechanisms of anthraquinones have not been fully elucidated. We investigated the activity of anthraquinones using acute inflammatory and nociceptive experimental conditions. Anthraquinone-2-carboxylic acid (9,10-dihydro-9,10-dioxo-2-anthracenecarboxylic acid, AQCA), one of the major anthraquinones identified from Brazilian taheebo, ameliorated various inflammatory and algesic symptoms in EtOH/HCl- and acetylsalicylic acid- (ASA-) induced gastritis, arachidonic acid-induced edema, and acetic acid-induced abdominal writhing without displaying toxic profiles in body and organ weight, gastric irritation, or serum parameters. In addition, AQCA suppressed the expression of inflammatory genes such as cyclooxygenase- (COX-) 2 in stomach tissues and lipopolysaccharide- (LPS-) treated RAW264.7 cells. According to reporter gene assay and immunoblotting analyses, AQCA inhibited activation of the nuclear factor- (NF-) κB and activator protein- (AP-) 1 pathways by suppression of upstream signaling involving interleukin-1 receptor-associated kinase 4 (IRAK1), p38, Src, and spleen tyrosine kinase (Syk). Our data strongly suggest that anthraquinones such as AQCA act as potent anti-inflammatory and antinociceptive components in vivo, thus contributing to the immune regulatory role of fruits and herbs.

  10. The effects of solvents and structure on the electronic absorption spectra of the isomeric pyridine carboxylic acid N-oxides

    Directory of Open Access Journals (Sweden)

    Drmanić Saša Ž.

    2013-01-01

    Full Text Available The ultraviolet absorption spectra of the carboxyl group of three isomeric pyridine carboxylic acids N-oxides (picolinic acid N-oxide, nicotinic acid N-oxide and isonicotinic acid N-oxide were determined in fourteen solvents in the wavelength range from 200 to 400 nm. The position of the absorption maxima (λmax of the examined acids showed that the ultraviolet absorption maximum wavelengths of picolinic acid N-oxide are the shortest, and those of isonicotinic acid N-oxide acid are the longest. In order to analyze the solvent effect on the obtained absorption spectra, the ultraviolet absorption frequencies of the electronic transitions in the carboxylic group of the examined acids were correlated using a total solvatochromic equation of the form max = v0 + sπ + aα+ bβ, where υmax is the absorption frequency (1/λmax, p is a measure of the solvent polarity, β represents the scale of solvent hydrogen bond acceptor basicities and α represent the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The solvent effects on the ultraviolet absorption maximums of the examined acids were discussed.

  11. Thermodynamic studies on corrosion inhibition of aqueous solutions of amino/carboxylic acids toward copper by EMF measurement

    International Nuclear Information System (INIS)

    Spah, Manjula; Spah, Dal Chand; Deshwal, Balraj; Lee, Seungmoon; Chae, Yoon-Keun; Park, Jin Won

    2009-01-01

    Electromotive force (E) measurements were made on an electrochemical cell [Cu x Hg|CuCl 2 (m) in a solvent S|AgCl-Ag] (where S is a dilute aqueous solution (0.01 m) of amino acid (glycine, alanine, methionine and glutamic acid) or aliphatic carboxylic acid (formic acid, acetic acid, n-butyric acid and glutaric acid)) at 30 deg. C. These measured E values were used to compute the dissociation constants (K 1 and K 2 ) and the degree of dissociation (α 1 and α 2 ) by iterative procedures. The standard cell potential (E o ) and the mean activity coefficient (γ ± ) of CuCl 2 were also determined. The E o data were next used to evaluate the Gibbs energy of transfer (ΔG tr 0 ) of CuCl 2 from water to dilute aqueous solutions of the amino/carboxylic acids. The negative ΔG tr 0 values suggested that these acids act as potential corrosion inhibitors. The magnitudes of ΔG tr 0 values show that the amino acids act as better corrosion inhibitors towards copper than the aliphatic carboxylic acids.

  12. Thermal- and photo-induced degradation of perfluorinated carboxylic acids: Kinetics and mechanism.

    Science.gov (United States)

    Liu, Jiaoqin; Qu, Ruijuan; Wang, Zunyao; Mendoza-Sanchez, Itza; Sharma, Virender K

    2017-12-01

    Perfluorinated carboxylic acids (PFCAs) of different carbon chain lengths are chemicals of concern to human health and their removal, using conventional remediation technologies, is challenging. The present paper pursuits thermal and photo-induced degradation of PFCAs (F(CF 2 ) n COOH, n = 1-9) under various concentrations of four different acids (HNO 3 , H 2 SO 4 , HCl, and H 3 PO 4 ) covering a range of strong acidic to basic pH. For thermal-induced experiments, the temperature was set at 40 °C, 60 °C, and 80 °C at acid strengths of 0.04-18.4 M. Photo-induced experiments were conducted at pH 0.5, 7.0, and 13.0 under a light intensity of (150 ± 10) × 100 μW/cm 2 . The degradation first-order rate constant (k 1, h -1 ) as a function of [H + ] was modeled by considering equilibrium of nondissociated (F(CF 2 ) n COOH, HX) and dissociated (F(CF 2 ) n COO - , X - ) species of PFCAs (HX ⇌ X -  + H + , pK a  = -0.1). Species-specific rate constants, k 1 HX , reasonably described the trend of thermal and photo decay of PFCAs, where k 1 HX increased with acidity of solution and the carbon chain length of PFCAs. Mechanism of degradation of PFCAs (e.g. perfluorooctanoic acid (PFOA)) involved homolytic breakage of CC bond between alkyl and carboxyl groups, which produced radicals and subsequently decarboxylation to perfluoroheptene-1. Density functional theory (DFT) calculations supported the mechanism. The calculations indicated that a breaking of CC bond is more feasible with nondissociated HX than dissociated X - species of PFCAs and also with increase in chain length. The potential of a combination of thermal- and photo-induced processes under acidic conditions to enhance degradation of PFOA in water is presented. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidities, photoelectron spectra, and computations on tyrosine, p-hydroxybenzoic acid, and their conjugate bases.

    Science.gov (United States)

    Tian, Zhixin; Wang, Xue-Bin; Wang, Lai-Sheng; Kass, Steven R

    2009-01-28

    Deprotonation of tyrosine in the gas phase was found to occur preferentially at the phenolic site, and the conjugate base consists of a 70:30 mixture of phenoxide and carboxylate anions at equilibrium. This result was established by developing a chemical probe for differentiating these two isomers, and the presence of both ions was confirmed by photoelectron spectroscopy. Equilibrium acidity measurements on tyrosine indicated that deltaG(acid)(o) = 332.5 +/- 1.5 kcal mol(-1) and deltaH(acid)(o) = 340.7 +/- 1.5 kcal mol(-1). Photoelectron spectra yielded adiabatic electron detachment energies of 2.70 +/- 0.05 and 3.55 +/- 0.10 eV for the phenoxide and carboxylate anions, respectively. The H/D exchange behavior of deprotonated tyrosine was examined using three different alcohols (CF3CH2OD, C6H5CH2OD, and CH3CH2OD), and incorporation of up to three deuterium atoms was observed. Two pathways are proposed to account for these results, and all of the experimental findings are supplemented with B3LYP/aug-cc-pVDZ and G3B3 calculations. In addition, it was found that electrospray ionization of tyrosine from a 3:1 (v/v) CH3OH/H2O solution using a commercial source produces a deprotonated [M-H]- anion with the gas-phase equilibrium composition rather than the structure of the ion that exists in aqueous media. Electrospray ionization from acetonitrile, however, leads largely to the liquid-phase (carboxylate) structure. A control molecule, p-hydroxybenzoic acid, was found to behave in a similar manner. Thus, the electrospray conditions that are employed for the analysis of a compound can alter the isomeric composition of the resulting anion.

  14. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    Directory of Open Access Journals (Sweden)

    M. Onciu

    2005-02-01

    Full Text Available Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP and pyridine (Py as bases and N-methyl-2-pyrolidinone (NMP as solvent, at reflux (180-190°C for 8-12 hours.

  15. Edible films developed from carboxylic acid cross-linked sesame protein isolate: barrier, mechanical, thermal, crystalline and morphological properties.

    Science.gov (United States)

    Sharma, Loveleen; Sharma, Harish Kumar; Saini, Charanjiv Singh

    2018-02-01

    Films were developed from sesame protein crosslinked with three different carboxylic acids (malic acid, citric acid and succinic acid) at 1, 3 and 5% (w/w, on protein isolate basis). The effect of crosslinking on physical, mechanical, thermal and morphological properties was studied. Succinic acid crosslinked films exhibited least water vapor permeability the highest tensile strength and overall showed superlative properties among other films. X-ray diffraction showed single main crystalline reflection at 20° indicating amorphous structure of films. DSC curves of films indicated single melting peak in the range of 103-161 °C. All films exhibited weight loss in three stages. FTIR exhibited peak at 1700 cm -1 confirming crosslinking reaction between carboxylic acids and protein. Crosslinked films were compact, nonporous and smooth as compared to film from native sesame protein isolate.

  16. Copper Complexes of Nicotinic-Aromatic Carboxylic Acids as Superoxide Dismutase Mimetics

    Directory of Open Access Journals (Sweden)

    Virapong Prachayasittikul

    2008-12-01

    Full Text Available Nicotinic acid (also known as vitamin B3 is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids. The tested copper complexes exhibited superoxide dismutase (SOD mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 μg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph was the most potent with a SOD mimetic activity of IC50 34.42 μM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO, were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to possess the lowest HOMO energy. These findings demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.

  17. A mechanistic study on the Hooker oxidation: synthesis of novel indane carboxylic acid derivatives from lapachol.

    Science.gov (United States)

    Eyong, Kenneth O; Puppala, Manohar; Kumar, Ponminor Senthil; Lamshöft, Marc; Folefoc, Gabriel N; Spiteller, Michael; Baskaran, Sundarababu

    2013-01-21

    The Hooker oxidation is one of the most intriguing transformations wherein lapachol (1) is readily converted to norlapachol (2) in very good yield. This one-pot reaction involves a very intricate mechanism in which the alkyl side chain of lapachol is shortened by one carbon unit. Previous studies have unequivocally established the involvement of an indane carboxylic acid derivative 3, as a key intermediate (Hooker intermediate), and its simultaneous conversion to norlapachol (2) via the oxidative cleavage of vicinol diol and subsequent intramolecular aldol reaction of the resulting keto acid. However, the formation of the key Hooker intermediate 3 from lapachol (1) remains ambiguous. The present study has thrown some light on the formation of the key intermediate 3 from lapachol (1) via benzilic acid rearrangement of the corresponding labile o-diquinone intermediate 8 derived from lapachol. The involvement of o-diquinone intermediate 8 in the Hooker oxidation has been further established by trapping of this labile intermediate as the corresponding phenazine derivative 9. The involvement of benzilic acid rearrangement as a key step in the Hooker oxidation is further shown with a variety of o-quinones prepared from lapachol (1).

  18. Liquid chromatographic determination of urinary 2-thiothiazolidine-4-carboxylic acid, a biomarker of carbon disulphide exposure.

    Science.gov (United States)

    Lee, B L; Yang, X F; New, A L; Ong, C N

    1995-06-23

    An effective gradient high-performance liquid chromatographic method for baseline separation of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA), with photodiode array detection at 271 nm was described. o-Methylhippuric acid was used as an internal standard (I.S.). A 1-ml urine sample was saturated with 300 mg of sodium sulphate, acidified with 100 microliters of 6 M hydrochloric acid, extracted twice with 2 ml of diethyl ether, and after evaporation, the residue was taken up in 1 ml of 0.1% (v/v) phosphoric acid. The two mobile phases used for gradient elution were: (A) 10 mM ammonium dihydrogenphosphate (pH 3.5) and (B) same concentration of buffer but containing 20% (v/v) of methanol (pH 4.8). The flow-rate was set at 1.0 ml/min. TTCA and I.S. were detected at 2.2 and 9.1 min, respectively. The method was validated with urine samples collected from normal subjects and workers occupationally exposed to carbon disulphide. The present method enables the detection of urinary TTCA at a concentration of 0.025 mg/l. Analytical recovery and reproducibility generally exceeded 90%. The proposed method is considered more sensitive, specific and reliable than other existing methods.

  19. What is the enthalpy of formation of pyrazine-2-carboxylic acid?

    International Nuclear Information System (INIS)

    Miranda, Margarida S.; Duarte, Darío J.R.; Liebman, Joel F.

    2016-01-01

    There are two contemporary conflicting, indeed, incompatible determinations of measurements of the enthalpies of combustion and of formation of pyrazine-2-carboxylic acid in the literature, (−2268.0 ± 0.9 and −271.2 ± 1.1 kJ · mol −1 ) and (−2211.4 ± 0.9 and −327.8 ± 1.1 kJ · mol −1 ). The current paper discusses these two sets of values and from the use of a measurement of the enthalpy of sublimation, a newly evaluated enthalpy of formation of pyrazine itself, and of the quantum chemical calculations at the G3(MP2)//B3LYP level, the former results are accepted and the derived gas phase enthalpy of formation, −(167.6 ± 3.1) kJ · mol −1 , suggested.

  20. Preparation of mono- and diacetyl 4,4′-dimethylbiphenyl and their corresponding carboxylic acids

    DEFF Research Database (Denmark)

    Titinchi, Salam J.J.; Kamounah, Fadhil S.; Abbo, Hanna S.

    2007-01-01

    Shape selective acetylation of 4,4′-dimethylbiphenyl using anhydrous aluminum chloride as catalyst is an effective route for the production of mono- and di-acetyl-4,4′-dimethylbiphenyl. Preparations, characterization and a catalytic study of the Friedel-Crafts acetylation of 4,4′-dimethylbiphenyl......, involving use of the Perrier addition procedure are carried out in a range of solvents and under a variety of experimental conditions. The obtained ketones are isolated and identified by various physico-chemical techniques. Mono acetylation of 4,4′-dimethylbiphenyl afforded a mixture of two isomeric acetyl...... dimethylbiphenyls. In chloroalkane or carbon disulfide solvent, the yields of isomers were in the order: 2 -> 3-; in nitromethane 3-isomer predominated. On the other hand diacetylation of the hydrocarbon gave only the 2,3′-diacetyl isomer. The mono- and di-ketones are converted to the corresponding carboxylic acids...

  1. Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

    Energy Technology Data Exchange (ETDEWEB)

    O’Donnell, Ryan M. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Sampaio, Renato N. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Li, Guocan [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Johansson, Patrik G. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Ward, Cassandra L. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Meyer, Gerald J. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States

    2016-03-10

    Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [RuII(btfmb)2(LL)]2+, [RuII(dtb)2(LL)]2+, and [RuII(bpy)2(LL)]2+, where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF3)2-bpy, and dtb is 4,4'-((CH3)3C)2-bpy, and LL is either dcb = 4,4'-(CO2H)2-bpy or mcb = 4-(CO2H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa’s of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pKa values for the commonly utilized dcb ligand, pKa1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [RuIII(btfmb–)L2]2+* localized excited state and a [RuIII(dcb–)L2]2+* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pKa* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).

  2. Metallaphotoredox-catalysed sp3-sp3 cross-coupling of carboxylic acids with alkyl halides

    Science.gov (United States)

    Johnston, Craig P.; Smith, Russell T.; Allmendinger, Simon; MacMillan, David W. C.

    2016-08-01

    In the past 50 years, cross-coupling reactions mediated by transition metals have changed the way in which complex organic molecules are synthesized. The predictable and chemoselective nature of these transformations has led to their widespread adoption across many areas of chemical research. However, the construction of a bond between two sp3-hybridized carbon atoms, a fundamental unit of organic chemistry, remains an important yet elusive objective for engineering cross-coupling reactions. In comparison to related procedures with sp2-hybridized species, the development of methods for sp3-sp3 bond formation via transition metal catalysis has been hampered historically by deleterious side-reactions, such as β-hydride elimination with palladium catalysis or the reluctance of alkyl halides to undergo oxidative addition. To address this issue, nickel-catalysed cross-coupling processes can be used to form sp3-sp3 bonds that utilize organometallic nucleophiles and alkyl electrophiles. In particular, the coupling of alkyl halides with pre-generated organozinc, Grignard and organoborane species has been used to furnish diverse molecular structures. However, the manipulations required to produce these activated structures is inefficient, leading to poor step- and atom-economies. Moreover, the operational difficulties associated with making and using these reactive coupling partners, and preserving them through a synthetic sequence, has hindered their widespread adoption. A generically useful sp3-sp3 coupling technology that uses bench-stable, native organic functional groups, without the need for pre-functionalization or substrate derivatization, would therefore be valuable. Here we demonstrate that the synergistic merger of photoredox and nickel catalysis enables the direct formation of sp3-sp3 bonds using only simple carboxylic acids and alkyl halides as the nucleophilic and electrophilic coupling partners, respectively. This metallaphotoredox protocol is suitable for

  3. Recovery of carboxylic acids produced during dark fermentation of food waste by adsorption on Amberlite IRA-67 and activated carbon.

    Science.gov (United States)

    Yousuf, Ahasa; Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye

    2016-10-01

    Amberlite IRA-67 and activated carbon were tested as promising candidates for carboxylic acid recovery by adsorption. Dark fermentation was performed without pH control and without addition of external inoculum at 37°C in batch mode. Lactic, acetic and butyric acids, were obtained, after 7days of fermentation. The maximum acid removal, 74%, from the Amberlite IRA-67 and 63% from activated carbon was obtained from clarified fermentation broth using 200gadsorbent/Lbroth at pH 3.3. The pH has significant effect and pH below the carboxylic acids pKa showed to be beneficial for both the adsorbents. The un-controlled pH fermentation creates acidic environment, aiding in adsorption by eliminating use of chemicals for efficient removal. This study proposes simple and easy valorization of waste to valuable chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Carboxylic acid reductase is a versatile enzyme for the conversion of fatty acids into fuels and chemical commodities.

    Science.gov (United States)

    Akhtar, M Kalim; Turner, Nicholas J; Jones, Patrik R

    2013-01-02

    Aliphatic hydrocarbons such as fatty alcohols and petroleum-derived alkanes have numerous applications in the chemical industry. In recent years, the renewable synthesis of aliphatic hydrocarbons has been made possible by engineering microbes to overaccumulate fatty acids. However, to generate end products with the desired physicochemical properties (e.g., fatty aldehydes, alkanes, and alcohols), further conversion of the fatty acid is necessary. A carboxylic acid reductase (CAR) from Mycobacterium marinum was found to convert a wide range of aliphatic fatty acids (C(6)-C(18)) into corresponding aldehydes. Together with the broad-substrate specificity of an aldehyde reductase or an aldehyde decarbonylase, the catalytic conversion of fatty acids to fatty alcohols (C(8)-C(16)) or fatty alkanes (C(7)-C(15)) was reconstituted in vitro. This concept was applied in vivo, in combination with a chain-length-specific thioesterase, to engineer Escherichia coli BL21(DE3) strains that were capable of synthesizing fatty alcohols and alkanes. A fatty alcohol titer exceeding 350 mg·L(-1) was obtained in minimal media supplemented with glucose. Moreover, by combining the CAR-dependent pathway with an exogenous fatty acid-generating lipase, natural oils (coconut oil, palm oil, and algal oil bodies) were enzymatically converted into fatty alcohols across a broad chain-length range (C(8)-C(18)). Together with complementing enzymes, the broad substrate specificity and kinetic characteristics of CAR opens the road for direct and tailored enzyme-catalyzed conversion of lipids into user-ready chemical commodities.

  5. Phase-separated structures of mixed Langmuir-Blodgett films of fatty acid and hybrid carboxylic acid.

    Science.gov (United States)

    Kimura, Hideto; Watanabe, Satoshi; Shibata, Hirobumi; Azumi, Reiko; Sakai, Hideki; Abe, Masahiko; Matsumoto, Mutsuyoshi

    2008-12-04

    Phase separation often occurs in mixed Langmuir-Blodgett (LB) films. Usually circular domains at the micrometer length scale form in the LB films. The size and shape of the domains are governed by a compromise between two competing interactions of line tension and dipole-dipole interaction. An attempt was made to control the line tension by varying systematically the hydrophobic moieties of the film-forming molecules. Phase-separated structures of two-component mixed LB films of fatty acid [C(k)H(2k+1)COOH (HkA)] and hybrid carboxylic acid [C(m)F(2m+1)C(n)H(2n)COOH (FmHnA)] were investigated. IR spectra of the mixed LB films of H17A and F8H10A revealed that the alkyl chains were in an all-trans conformation and that the molecular orientation remained unchanged when the two components were mixed. Nanowires formed in the mixed LB films of HkA and F8H10A. The width of the nanowires increased with an increase in k. Domain size and shape in the mixed LB films of H17A and FmHnA depended strongly on the values of m and n. Circular domains at the micrometer length scale formed in the region m + n or = 16 except for F6H10A. These results were explained by using a lattice model that considers the effect of the hydrophobic moieties of fatty acid and hybrid carboxylic acid on the line tension.

  6. LIQUID-CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC-ACIDS USING N-(4-AMINOBUTYL)-N-ETHYLISOLUMINOL AS CHEMILUMINESCENT LABEL - DETERMINATION OF IBUPROFEN IN SALIVA

    NARCIS (Netherlands)

    STEIJGER, OM; LINGEMAN, H; BRINKMAN, UAT; HOLTHUIS, JJM; SMILDE, AK; DOORNBOS, DA

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  7. Liquid chromatographic analysis of carboxylic acids using N-(4-aminobutyl)-N-ethylisoluminol as chemiluminescent label: determination of ibuprofen in saliva

    NARCIS (Netherlands)

    Steijger, O. M.; Lingeman, H.; Brinkman, U. A.; Holthuis, J. J.; Smilde, A. K.; Doornbos, D. A.

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  8. Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

    Directory of Open Access Journals (Sweden)

    Ali Ahmed Mahmoud Abdelhaleem

    2015-06-01

    Full Text Available This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ and various carboxylic acid plasticizers (CAPs. The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2 showed the highest dissolution percentage (> 95 % in 20 minutes compared to pure crystalline CZ (56 %. Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

  9. Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions and sulfonamide groups.

    Science.gov (United States)

    Rayne, Sierra; Forest, Kaya

    2010-01-01

    Temperature-dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the S(N)1 and S(N)2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degradation. Abiotic hydrolysis of monomeric FTAcrs may be a significant contributor to current environmental loadings of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylic acids (PFCAs). Polymeric FTAcrs are expected to be hydrolyzed more slowly, with estimated half-lives in soil and natural waters ranging between several centuries to several millenia absent additional surface area limitations on reactivity. Poor agreement was found between the limited experimental data on FTPE hydrolysis and computational estimates, requiring more detailed experimental data before any further modeling can occur on these compounds or their perfluoroalkyl sulfonamidoethanol phosphate ester (PFSamPE) analogs. FTIs are expected to have hydrolytic half-lives of about 130 days in most natural waters, suggesting they may be contributing to substantial FTOH and PFCA inputs in aquatic systems. Perfluoroalkyl sulfonamides (PFSams) appear unlikely to undergo abiotic hydrolysis at the S-N, C-S, or N-C linkages under environmentally relevant conditions, although potentially facile S-N hydrolysis via intramolecular catalysis by ethanol and acetic acid amide substituents warrants further investigation.

  10. Equilibrium studies of ternary systems containing some selected transition metal ions, triazoles and aromatic carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Mohamed Magdy; Radalla, Abd-Elatty; Qasem, Fatma; Khaled, Rehab [Beni-Suef University, Beni-Suef (Egypt)

    2014-01-15

    Solution equilibria of the binary and ternary complex systems of the divalent transition metal ions Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+} with 1,2,4-triazole (TRZ), 3-mercapto-1,2,4-triazole (TRZSH), and 3-amino-1,2,4-triazole (TRZAM) and aromatic carboxylic acids (phthalic, anthranilic, salicylic, and 5-sulfosalicylic acid) have been studied pH-metrically at (25.0±0.1) .deg. C, and a constant ionic strength I=1x10{sup -1} mol L{sup -1} NaNO{sub 3} in an aqueous medium. The potentiometric titration curves show that binary and ternary complexes of these ligands are formed in solution. The stability constants of the different binary and ternary complexes formed were calculated on the basis of computer analysis of the titration data. The relative stability of the different ternary complex species is expressed in terms of Δ log K values, log X and R. S.% parameters. The effect of temperature of the medium on both the proton-ligand equilibria for TRZAM and phthalic acid and their metal-ligand equilibria with Cu{sup 2+}, Ni{sup 2+}, and Co{sup 2+} has been studied along with the corresponding thermodynamic parameters. The complexation behavior of ternary complexes is ascertained using conductivity measurements. In addition, the formation of ternary complexes in solution has been confirmed by using UV-visible spectrophotometry.

  11. Erbium trifluoromethanesulfonate-catalyzed Friedel–Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Hansen, Poul Erik; Nguyen, Hai Truong

    2015-01-01

    Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel–Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation...

  12. Tropanol esters of metallocene carboxylic acids. Syntheses, labelling with 103Ru and sup(103m)Rh and organ distribution

    International Nuclear Information System (INIS)

    Wenzel, M.; Wu, Y.

    1988-01-01

    The tropanol esters of the carboxylic acids of ferrocene, 103 Ru-ruthenocene and sup(103m)Rh-rhodocinium were synthezised. The organ distribution of the 103 Ru or sup(103m)Rh labelled tropanol-esters were investigated. Only the 103 Ru labelled ester showed a high heart/blood ratio. (author)

  13. 7-(3-Chlorophenylamino-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Ghassan F. Shattat

    2010-03-01

    Full Text Available 7-(3-Chlorophenylamino-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (2 was prepared and fully characterized by NMR, IR, and MS. Compound 2 exhibited good antibacterial activity against gram-positive standard and resistant strains.

  14. Significant enhancement of PEDOT thin film adhesion to inorganic solid substrates with EDOT-acid.

    Science.gov (United States)

    Wei, Bin; Liu, Jinglin; Ouyang, Liangqi; Kuo, Chin-Chen; Martin, David C

    2015-07-22

    With its high conductivity, tunable surface morphology, relatively soft mechanical response, high chemical stability, and excellent biocompatibility, poly(3,4-ethylenedioxythiophene) (PEDOT) has become a promising coating material for a variety of electronic biomedical devices. However, the relatively poor adhesion of PEDOT to inorganic metallic and semiconducting substrates still poses challenges for long-term applications. Here, we report that 2,3-dihydrothieno(3,4-b)(1,4)dioxine-2-carboxylic acid (EDOT-acid) significantly improves the adhesion between PEDOT thin films and inorganic solid electrodes. EDOT-acid molecules were chemically bonded onto activated oxide substrates via the chemisorption of the carboxylic groups. PEDOT was then polymerized onto the EDOT-acid modified substrates, forming covalently bonded coatings. The adsorption of EDOT-acid onto the electrode surfaces was characterized by cyclic voltammetry (CV), contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy. The electrical properties of the subsequently coated PEDOT films were studied by electrochemical impedance spectroscopy and CV. An aggressive ultrasonication test confirmed the significantly improved adhesion and mechanical stability of the PEDOT films on electrodes with EDOT-acid treatment over those without treatment.

  15. Enhancing Cooperativity in Bifunctional Acid–Pd Catalysts with Carboxylic Acid-Functionalized Organic Monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Coan, Patrick D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Ellis, Lucas D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Griffin, Michael B. [National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Schwartz, Daniel K. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Medlin, J. Will [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States

    2018-03-01

    Cooperative catalysts containing a combination of noble metal hydrogenation sites and Bronsted acid sites are critical for many reactions, including the deoxygenation (DO) of biomass-derived oxygenates in the upgrading of pyrolysis oil. One route toward the design of cooperative catalysts is to tether two different catalytically active functions so that they are in close proximity while avoiding undesirable interactions that can block active sites. Here, we deposited carboxylic acid (CA)-functionalized organophosphonate monolayers onto Al2O3-supported Pd nanoparticle catalysts to prepare bifunctional catalysts containing both Bronsted acid and metal sites. Modification with phosphonic acids (PAs) improved activity and selectivity for gas-phase DO reactions, but the degree of improvement was highly sensitive to both the presence and positioning of the CA group, suggesting a significant contribution from both the PA and CA sites. Short spacer lengths of 1-2 methylene groups between the phosphonate head and CA tail were found to yield the best DO rates and selectivities, whereas longer chains performed similarly to self-assembled monolayers having alkyl tails. Results from a combination of density functional theory and Fourier transform infrared spectroscopy suggested that the enhanced catalyst performance on the optimally positioned CAs was due to the generation of strong acid sites on the Al2O3 support adjacent to the metal. Furthermore, the high activity of these sites was found to result from a hydrogen-bonded cyclic structure involving cooperativity between the phosphonate head group and CA tail function. More broadly, these results indicate that functional groups tethered to supports via organic ligands can influence catalytic chemistry on metal nanoparticles.

  16. Measurements of atmospheric carboxylic acids and carbonyl compounds in São Paulo City, Brazil.

    Science.gov (United States)

    Montero, L; Vasconcellos, P C; Souza, S R; Pires, M A; Sanchez-Ccoyllo, O R; Andrade, M F; Carvalho, L R

    2001-08-01

    Winter atmospheric measurements of gaseous lower carbonyl and carboxylic acids were carried out simultaneously (in 1999) at two distinct urban sites located in the city of São Paulo, Brazil. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. It has an unconventional mix of vehicle types in that a variety of gasoline blends, including oxygenated ones, are used. Mixing ratios of formic and acetic acids ranged, respectively, from 0.6 to 19.4 and from 0.1 to 10.6 ppbv in one of the sites studied and from 1.4 to 18.4 and from 0.4 to 6.7 ppbv in the other site. High values of formic to acetic ratios were found, especially in the latter site (average = 4.3), suggesting that photochemical production was the predominant source of the formic and acetic acid during the afternoon. Differing from the acids, levels of carbonyls were similar at both sites. Higher average mixing ratios of acetaldehyde and formaldehyde were found in the morning (18.9 and 17.2 ppbv) and gradually decreased from midday (9.5 and 11.8 ppbv) to evening (7.2 and 10.2 ppbv). In the morning, vehicular direct emission seemed to be the main primary source of formaldehyde and acetaldehyde, whereas at midday and evening these compounds appeared to be mainly formed by photochemistry. Secondary photochemical production of organic acids and aldehydes (rather than primary emissions from vehicles) was shown to be more important in São Paulo's atmosphere from midday to evening, particularly on days with strong solar radiation.

  17. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

    Czech Academy of Sciences Publication Activity Database

    Hermann, K.; Meinhard, J.; Dobrev, Petre; Linkies, A.; Pešek, Bedřich; Heß, B.; Macháčková, Ivana; Fischer, U.; Leubner-Metzger, G.

    2007-01-01

    Roč. 58, č. 11 (2007), s. 3047-3060 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid (ABA) * ABA 8'-hydroxylase (CYP707A) * 1-aminocyclopropane-1-carboxylic acid (ACC) Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  18. Evaluation of the physico-chemical properties of acid thinned ...

    African Journals Online (AJOL)

    The effect of acid hydrolysis on the physico-chemical properties of cassava starch was investigated. The acid hydrolysed (acid thinned) starches were prepared from cassava starch with 0.1M solution of hydrochloric acid. The acid hydrolysis of starch samples were carried out at 60°C in a thermostatically controlled water ...

  19. Syn vs Anti Carboxylic Acids in Hybrid Peptides: Experimental and Theoretical Charge Density and Chemical Bonding Analysis.

    Science.gov (United States)

    Pal, Rumpa; Reddy, M B Madhusudana; Dinesh, B; Venkatesha, Manjunath A; Grabowsky, Simon; Jelsch, Christian; Guru Row, Tayur N

    2018-04-12

    A comparative study of syn vs anti carboxylic acids in hybrid peptides based on experimental electron density studies and theoretical calculations shows that, in the anti form, all three bond angles surrounding C carboxyl of the -COOH group are close to ∼120°, as expected for a C-sp 2 atom, whereas in the syn form, the ∠C α -C(O)-O hydroxyl angle is significantly smaller by 5-10°. The oxygen atom in the carboxyl group is more electronegative in the anti form, so the polarity of the acidic O-H bond is higher in the anti form compared to the syn form, as observed within the limitations of H atom treatment in X-ray diffraction. Consequently, the investigated anti carboxylic acid forms the strongest O-H···O hydrogen bond among all model compounds. Furthermore, according to natural bond orbital analysis, the oxygen lone pairs are clearly nonequivalent, as opposed to the general notion of hybridization of equivalent sp 2 and sp 3 lone pairs on carbonyl or hydroxyl oxygen atoms. The hybridization of the lone pairs is directly related to the directionality and strength of hydrogen bonds.

  20. 1-Aminocyclopropane-1-carboxylic acid (ACC in plants: more than just the precursor of ethylene!

    Directory of Open Access Journals (Sweden)

    Bram eVan de Poel

    2014-11-01

    Full Text Available Ethylene is a simple two carbon atom molecule with profound effects on plants. There are quite a few review papers covering all aspects of ethylene biology in plants, including its biosynthesis, signaling and physiology. This is merely a logical consequence of the fascinating and pleiotropic nature of this gaseous plant hormone. Its biochemical precursor, 1-aminocyclopropane-1-carboxylic acid (ACC is also a fairly simple molecule, but perhaps its role in plant biology is seriously underestimated. This triangularly-shaped amino acid has many more features than just being the precursor of the lead-role player ethylene. For example, ACC can be conjugated to three different derivatives, but their biological role remains vague. ACC can also be metabolized by bacteria using ACC-deaminase, favoring plant growth and lowering stress susceptibility. ACC is also subjected to a sophisticated transport mechanism to ensure local and long-distance ethylene responses. Last but not least, there are now a few exciting studies where ACC has been reported to function as a signal itself, independently from ethylene. This review puts ACC in the spotlight, not to give it the lead-role, but to create a picture of the stunning co-production of the hormone and its precursor.

  1. 1-aminocyclopropane-1-carboxylic acid (ACC) in plants: more than just the precursor of ethylene!

    Science.gov (United States)

    Van de Poel, Bram; Van Der Straeten, Dominique

    2014-01-01

    Ethylene is a simple two carbon atom molecule with profound effects on plants. There are quite a few review papers covering all aspects of ethylene biology in plants, including its biosynthesis, signaling and physiology. This is merely a logical consequence of the fascinating and pleiotropic nature of this gaseous plant hormone. Its biochemical precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) is also a fairly simple molecule, but perhaps its role in plant biology is seriously underestimated. This triangularly shaped amino acid has many more features than just being the precursor of the lead-role player ethylene. For example, ACC can be conjugated to three different derivatives, but their biological role remains vague. ACC can also be metabolized by bacteria using ACC-deaminase, favoring plant growth and lowering stress susceptibility. ACC is also subjected to a sophisticated transport mechanism to ensure local and long-distance ethylene responses. Last but not least, there are now a few exciting studies where ACC has been reported to function as a signal itself, independently from ethylene. This review puts ACC in the spotlight, not to give it the lead-role, but to create a picture of the stunning co-production of the hormone and its precursor. PMID:25426135

  2. Biomass-based production of low-molecular-mass aliphatic carboxylic acids - BioHap

    Energy Technology Data Exchange (ETDEWEB)

    Alen, R.; Paloheimo, T.; Markkanen, E.; Louhelainen, J. (Jyvaeskylae Univ. (Finland). Dept. of Chemistry), Email: raimo.j.alen@jyu.fi; Viikari, L.; Martikainen, J. (Helsinki Univ. (Finland). Dept. of Applied Chemsitry and Microbiology), Email: liisa.viikari@helsinki.fi

    2010-10-15

    The suitability of the Propionibacterium acidipropionici (ATCC 4875) strain was studied for producing aliphatic carboxylic acids (mainly propionic acid) from wood-derived monosaccharides as carbon sources by fermentation. The optimal treatment conditions based on the separate experiments with model substrates (glucose and xylose) were applied to a mixture of carbohydrates (about 75% of the dry solids) in various hydrolysates from the hot-water treatment (at 150 deg C for 120 min) of pine and birch chips (the total dissolved material 10-15% of the feedstock dry solids) prior to kraft pulping. In the latter case, the oligo- and polysaccharides were first hydrolysed by enzymes to fermentable monosaccharides (hexoses and pentoses). The results indicated that a yield of about 50% of the consumed sugars (theoretical yield 54%) could be obtained and the fermentation was not significantly disturbed, for example, by the presence of possible inhibitors (i.e., lignin-derived aromatics, extractives and furans) present in small amounts in all hydrolysates. This preliminary study offers useful data for the forthcoming studies aiming at a fullscale application. (orig.)

  3. Carboxyl terminal domain basic amino acids of mycobacterial topoisomerase I bind DNA to promote strand passage.

    Science.gov (United States)

    Ahmed, Wareed; Bhat, Anuradha Gopal; Leelaram, Majety Naga; Menon, Shruti; Nagaraja, Valakunja

    2013-08-01

    Bacterial DNA topoisomerase I (topoI) carries out relaxation of negatively supercoiled DNA through a series of orchestrated steps, DNA binding, cleavage, strand passage and religation. The N-terminal domain (NTD) of the type IA topoisomerases harbor DNA cleavage and religation activities, but the carboxyl terminal domain (CTD) is highly diverse. Most of these enzymes contain a varied number of Zn(2+) finger motifs in the CTD. The Zn(2+) finger motifs were found to be essential in Escherichia coli topoI but dispensable in the Thermotoga maritima enzyme. Although, the CTD of mycobacterial topoI lacks Zn(2+) fingers, it is indispensable for the DNA relaxation activity of the enzyme. The divergent CTD harbors three stretches of basic amino acids needed for the strand passage step of the reaction as demonstrated by a new assay. We also show that the basic amino acids constitute an independent DNA-binding site apart from the NTD and assist the simultaneous binding of two molecules of DNA to the enzyme, as required during the catalytic step. Although the NTD binds to DNA in a site-specific fashion to carry out DNA cleavage and religation, the basic residues in CTD bind to non-scissile DNA in a sequence-independent manner to promote the crucial strand passage step during DNA relaxation. The loss of Zn(2+) fingers from the mycobacterial topoI could be associated with Zn(2+) export and homeostasis.

  4. Molecular hybrids of CdSe semiconductor nanocrystals with terthiophene carboxylic acid or its polymeric analogue

    Energy Technology Data Exchange (ETDEWEB)

    Pokrop, Rafal; Pamula, Katarzyna; Deja-Drogomirecka, Sylwia; Zagorska, Malgorzata [Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00 664 Warsaw (Poland); Reiss, Peter [SPrAM (UMR 5819 CEA-CNRS-Univ. J. Fourier-Grenoble I)/LEMOH, CEA Grenoble/INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Louarn, Guy [Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes-CNRS, 2 rue de la Houssiniere, 44322 Nantes Cedex 3 (France); Chandezon, Frederic, E-mail: frederic.chandezon@cea.fr [SPrAM (UMR 5819 CEA-CNRS-Univ. J. Fourier-Grenoble I)/LEMOH, CEA Grenoble/INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Pron, Adam [SPrAM (UMR 5819 CEA-CNRS-Univ. J. Fourier-Grenoble I)/LEMOH, CEA Grenoble/INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2010-10-01

    Hybrid materials consisting of CdSe nanocrystals (CdSe NCs) and 7-(4,4''-dioctyl-2,2':5',2''-terthiophene-3'-yl)heptanoic acid (TTHA) or its high molecular analogue-poly(7-(4,4''-dioctyl-2,2':5',2''-terthiophene-3'-yl)heptanoic acid) (PTTHA) have been prepared from TOPO capped NCs via ligand exchange. Detailed spectroscopic and spectroelectrochemical (UV-vis-NIR, Raman) studies of these hybrids enabled us to determine the alignment of the HOMO and LUMO levels of their components. Since, for NCs of 3.7 nm, the alignment of the energy levels in both hybrids is staggered, the elaborated new materials are of potential use in photovoltaic devices. In the CdSe-PTTHA hybrid material a uniform distribution of the NCs within the polymer matrix is evidenced by TEM images. This is caused by strong interactions between nanocrystals surface and coordinating carboxylic function of the polymer.

  5. Oxidation of ethoxylated fatty alcohols to alkylpolyglycol carboxylic acids using noble metals as catalysts

    Directory of Open Access Journals (Sweden)

    Sagredos, Angelos

    2009-09-01

    Full Text Available The conversion of ethoxylated fatty alcohols to the corresponding carboxylic acids through dehydrogenation/ oxidation using noble-metal catalysts has been studied. Ethoxylated primary aliphatic alcohols, ethoxylated random secondary aliphatic alcohols and ethoxylated alkylphenols have been converted to the corresponding acids in the presence of a base. The noble metal catalysts Palladium and Platinum were used without significant degradation of the ethoxyl chain in yields that exceeded 90%. On the other hand, the catalysts Rhodium and Ruthenium gave yields of about 80% and 60% respectively.La conversión de alcoholes grasos etoxilados a los correspondientes ácidos carboxílicos por deshidrogenación/ oxidación con metales nobles como catalizador ha sido estudiada. Alcoholes primarios alifáticos etoxilados, alcoholes alifáticos secundarios etoxilados al azar y alquilfenoles etoxilados han sido convertidos a los correspondientes ácidos en presencia de base. Los catalizadores paladio y platino fueron usados sin degradación significativa de las cadenas etoxiladas con un rendimiento que excedió del 90%. Por otra parte catalizadores de rodio y rutenio produjeron rendimientos del 80 y 60%, respectivamente.

  6. Reaction kinetics for the biocatalytic conversion of phenazine-1-carboxylic acid to 2-hydroxyphenazine.

    Directory of Open Access Journals (Sweden)

    Mingmin Chen

    Full Text Available The phenazine derivative 2-hydroxyphenazine (2-OH-PHZ plays an important role in the biocontrol of plant diseases, and exhibits stronger bacteriostatic and fungistatic activity than phenazine-1-carboxylic acid (PCA toward some pathogens. PhzO has been shown to be responsible for the conversion of PCA to 2-OH-PHZ, however the kinetics of the reaction have not been systematically studied. Further, the yield of 2-OH-PHZ in fermentation culture is quite low and enhancement in our understanding of the reaction kinetics may contribute to improvements in large-scale, high-yield production of 2-OH-PHZ for biological control and other applications. In this study we confirmed previous reports that free PCA is converted to 2-hydroxy-phenazine-1-carboxylic acid (2-OH-PCA by the action of a single enzyme PhzO, and particularly demonstrate that this reaction is dependent on NADP(H and Fe3+. Fe3+ enhanced the conversion from PCA to 2-OH-PHZ and 28°C was a optimum temperature for the conversion. However, PCA added in excess to the culture inhibited the production of 2-OH-PHZ. 2-OH-PCA was extracted and purified from the broth, and it was confirmed that the decarboxylation of 2-OH-PCA could occur without the involvement of any enzyme. A kinetic analysis of the conversion of 2-OH-PCA to 2-OH-PHZ in the absence of enzyme and under different temperatures and pHs in vitro, revealed that the conversion followed first-order reaction kinetics. In the fermentation, the concentration of 2-OH-PCA increased to about 90 mg/L within a red precipitate fraction, as compared to 37 mg/L within the supernatant. The results of this study elucidate the reaction kinetics involved in the biosynthesis of 2-OH-PHZ and provide insights into in vitro methods to enhance yields of 2-OH-PHZ.

  7. On the possibility of using short chain length mono-carboxylic acids for stabilization of magnetic fluids

    Energy Technology Data Exchange (ETDEWEB)

    Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna Moscow Region (Russian Federation)]. E-mail: avd@nf.jinr.ru; Bica, Doina [Laboratory of Magnetic Fluids, CFATR, Romanian Academy, Timisoara Division, Timisoara (Romania); Vekas, Ladislau [National Center for Engineering of Systems with Complex Fluids, University Politehnica, Timisoara (NC ESCF-UPT) (Romania); Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Marinica, Oana [National Center for Engineering of Systems with Complex Fluids, University Politehnica, Timisoara (NC ESCF-UPT) (Romania); Balasoiu, Maria [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna Moscow Region (Russian Federation); Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary); Aksenov, Victor L. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna Moscow Region (Russian Federation); Rosta, Laszlo [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Garamus, Vasil M. [GKSS Research Centre, Geesthacht (Germany); Schreyer, Andreas [GKSS Research Centre, Geesthacht (Germany)

    2007-04-15

    Short chain length mono-carboxylic acids (lauric and myristic acids) are used to coat magnetite nanoparticles in non-polar organic liquids, which results in highly stable magnetic fluids. The new fluids are compared with classical organic fluids stabilized by oleic acid (OA). Magnetic granulometry and small-angle neutron scattering (polarized mode) reveal a great difference in the particle size distribution function for the studied magnetic fluids, particularly a decrease in the characteristic particle radius of magnetite when lauric and myristic acids are used instead of OA.

  8. 2-substituted thiazolidine-4(R)-carboxylic acids as prodrugs of L-cysteine. Protection of mice against acetaminophen hepatotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, H.T.; Goon, D.J.; Muldoon, W.P.; Zera, R.T.

    1984-05-01

    A number of 2-alkyl- and 2-aryl-substituted thiazolidine-4(R)-carboxylic acids were evaluated for their protective effect against hepatotoxic deaths produced in mice by LD/sub 90/ doses of acetaminophen. 2(RS)-Methyl-, 2(RS)-n-propyl-, and 2(RS)-n- pentylthiazolidine -4(R)-carboxylic acids (compounds 1b,d,e, respectively) were nearly equipotent in their protective effect based on the number of surviving animals at 48 h as well as by histological criteria. 2(RS)-Ethyl-, 2(RS)-phenyl-, and 2(RS)-(4-pyridyl)thiazolidine-4(R)-carboxylic acids (compounds 1c,f,g) were less protective. The enantiomer of 1b, viz., 2(RS)- methylthiazolidine -4(S)-carboxylic acid (2b), was totally ineffective in this regard. Thiazolidine-4(R)-carboxylic acid (1a), but not its enantiomer, 2a, was a good substrate for a solubilized preparation of rat liver mitochondrial proline oxidase (K/sub m/ 1.1 x 10(-4) M; V/sub max/ . 5.4 mumol min-1 (mg of protein)-1). Compound 1b was not a substrate for proline oxidase but dissociated to L-cysteine in this system. At physiological pH and temperature, the hydrogens on the methyl group of 1b underwent deuterium exchange with solvent D/sub 2/O (k1 . 2.5 X 10(-5) s), suggesting that opening of the thiazolidine ring must have taken place. Indeed, 1b labeled with /sup 14/C in the 2 and methyl positions was rapidly metabolized by the rat to produce /sup 14/CO/sub 2/, 80% of the dose being excreted in this form in the expired air after 24 h. It is suggested that these 2-substituted thiazolidine-4(R)-carboxylic acids are prodrugs of L-cysteine that liberate this sulfhydryl amino acid in vivo by nonenzymatic ring opening, followed by solvolysis.

  9. Phosphazene-promoted metal-free ring-opening polymerization of ethylene oxide initiated by carboxylic acid

    KAUST Repository

    Zhao, Junpeng

    2014-03-11

    The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP4) used as promoter. Kinetic study showed an induction period, i.e., transformation of carboxylic acid to hydroxyl ester, followed by slow chain growth together with simultaneous and fast end-group transesterification, which led to poly(ethylene oxide) (PEO) consisting of monoester (monohydroxyl), diester, and dihydroxyl species. An appropriate t-BuP4/acid ratio was proven to be essential to achieve better control over the polymerization and low dispersity of PEO. This work provides important information and enriches the toolbox for macromolecular and biomolecular engineering with protic initiating sites. © 2014 American Chemical Society.

  10. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    Science.gov (United States)

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Synthesis, Antifungal Activity and QSAR of Some Novel Carboxylic Acid Amides

    Directory of Open Access Journals (Sweden)

    Shijie Du

    2015-03-01

    Full Text Available A series of novel aromatic carboxylic acid amides were synthesized and tested for their activities against six phytopathogenic fungi by an in vitro mycelia growth inhibition assay. Most of them displayed moderate to good activity. Among them N-(2-(1H-indazol-1-ylphenyl-2-(trifluoromethylbenzamide (3c exhibited the highest antifungal activity against Pythium aphanidermatum (EC50 = 16.75 µg/mL and Rhizoctonia solani (EC50 = 19.19 µg/mL, compared to the reference compound boscalid with EC50 values of 10.68 and 14.47 µg/mL, respectively. Comparative molecular field analysis (CoMFA and comparative molecular similarity indices analysis (CoMSIA were employed to develop a three-dimensional quantitative structure-activity relationship model for the activity of the compounds. In the molecular docking, a fluorine atom and the carbonyl oxygen atom of 3c formed hydrogen bonds toward the hydroxyl hydrogens of TYR58 and TRP173.

  12. Synthesis, spectroscopic and DFT studies of novel 4-(morpholinomethyl)-5-oxo-1-phenylpyrrolidine-3-carboxylic acid

    Science.gov (United States)

    Devi, Poornima; Fatma, Shaheen; Bishnoi, Abha; Srivastava, Krishna; Shukla, Shraddha; Kumar, Roop

    2018-04-01

    A novel 4-(morpholinomethyl)-5-oxo-1-phenylpyrrolidine-3-carboxylic acid has been synthesized and its structural elucidation has been done by UV, FT-IR, 1H and 13C NMR spectroscopy. All quantum chemical calculations were carried out at level of density functional theory (DFT) with B3LYP function using 6-31G (d, p) basis atomic set. AIM approach has been incorporated for the analysis of various intermolecular interactions. Polarizability and hyperpolarizabilities values have been calculated along with the exploration of nonlinear optical properties of the title compound. DFT computed total first static hyperpolarizability (β0 = 0.2747 × 10-30 esu) indicates that title molecule could be an area of interest as an attractive future NLO material. For the analysis of thermal behaviour of title molecule, thermodynamic properties such as heat capacity, entropy and enthalpy change at various temperatures have been calculated. The NBO computations were done for the correlation of possible transitions with the electronic transitions. Electrophilic and nucleophilic regions were identified with the help of MESP plot. Determination of energy gap has been done by using HOMO and LUMO energy values, along with the computation of electronegativity and electrophilicity indices.

  13. A Precise Method for Processing Data to Determine the Dissociation Constants of Polyhydroxy Carboxylic Acids via Potentiometric Titration.

    Science.gov (United States)

    Huang, Kaixuan; Xu, Yong; Lu, Wen; Yu, Shiyuan

    2017-12-01

    The thermodynamic dissociation constants of xylonic acid and gluconic acid were studied via potentiometric methods, and the results were verified using lactic acid, which has a known pKa value, as a model compound. Solutions of xylonic acid and gluconic acid were titrated with a standard solution of sodium hydroxide. The determined pKa data were processed via the method of derivative plots using computer software, and the accuracy was validated using the Gran method. The dissociation constants associated with the carboxylic acid group of xylonic and gluconic acids were determined to be pKa 1  = 3.56 ± 0.07 and pKa 1  = 3.74 ± 0.06, respectively. Further, the experimental data showed that the second deprotonation constants associated with a hydroxyl group of each of the two acids were pKa 2  = 8.58 ± 0.12 and pKa 2  = 7.06 ± 0.08, respectively. The deprotonation behavior of polyhydroxy carboxylic acids was altered using various ratios with Cu(II) to form complexes in solution, and this led to proposing a hypothesis for further study.

  14. Difference between Extra- and Intracellular T1 Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR

    DEFF Research Database (Denmark)

    Karlsson, Magnus; Jensen, Pernille Rose; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    on the quantification of intracellular metabolicactivity. It is expected that the significantly shorter T1valueof the carboxylic moieties inside cells is a result of macro-molecular crowding. An artificial cytosol has been preparedand applied to predict the T1of other carboxylic acids. Wedemonstrate the value...

  15. Short-chain carboxylic acids, a new class of teratogens: studies of potential biochemical mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, M.E.; Rawlings, S.J.; Brown, N.A.

    1986-12-01

    Certain short-chain carboxylic acids (SCCA) appear to share a common teratogenic potential, although the structural requirements for activity remain obscure. By using a whole rat embryo culture model system, several biochemical processes have been examined, either as potential initial sites of teratogenic action or as early steps in the pathway to malformation. Valproate, methoxyacetate, and butyrate were the prototype SCCA examined. Measurement of (/sup 14/C)glucose utilization and lactate production confirmed that energy production by the early organogenesis embryo is predominantly from glycolysis. While the positive control agent, iodoacetate, caused a significant inhibition of lactate production, none of the SCCA affected this process or glucose utilization at teratogenic concentrations. Pinocytosis by the visceral yolk sac (VYS) was measured by the uptake of (/sup 125/I)polyvinylpyrrolidone. This process ultimately supplies the embryo with amino-acids and is essential for normal development. SCCA induce morphological abnormalities of the VYS in embryo culture. Pinocytosis was slightly reduced by valproate, but not the other SCCA. However, comparison with the action of an antiserum, for which inhibition of pinocytosis is the initial teratogenic insult, suggests that this is not the mechanism for valproate. Incorporation of (/sup 3/H)thymidine into embryo or yolk sac was not affected after 3 hr of SCCA exposure, but there was a marked effect of the positive control, hydroxyurea. This suggests that DNA synthesis is not directly influenced by SCCA. It can be concluded that SCCA do not exert their teratogenic effects by actions on glycolysis; maintenance of cellular acetyl CoA; pinocytosis or DNA synthesis. These observations contrast with preliminary results which suggest significant effects of SCCA on embryonic and yolk sac lipid metabolic pathways.

  16. Solubility and spectroscopic studies of the interaction of palladium with simple carboxylic acids and fulvic acid at low temperature

    Science.gov (United States)

    Wood, Scott A.; Tait, C. Drew; Vlassopoulos, Dimitri; Janecky, D. R.

    1994-01-01

    The interaction of Pd with some O-donor organic acid anions has been investigated using solubility measurements and a variety of spectroscopic techniques (UV-visible, Raman, FTIR, 13C NMR). Some of the ligands investigated (acetate, oxalate and fulvic acid) occur naturally in relatively high concentrations, whereas others (phthalate and salicylate) serve as models of potential binding sites on humic and fulvic acids. Solubility measurements show that the presence of acetate, phthalate, salicylate and fulvic acid (oxalate was not studied via solubility methods) can increase the mobility of Pd over various pH ranges, depending on the organic ligand. In the case of acetate, UV-visible and Raman spectroscopy ( 13C NMR results were inconclusive) provide strong evidence for the formation of electrostatically bound, possibly outer-sphere palladium acetate complexes. Oxalate was confirmed by UV-visible and FTIR spectroscopy to compete favorably with chloride (0.56 M NaCl) for Pd even at oxalate concentrations as low as 1 mM at pH = 6-7. Available data from the literature suggest that oxalate may have an influence on Pd mobility at free oxalate concentrations as low as 10 -8-10 -9 M. UV-visible spectroscopy provides evidence of an initially rapid, followed by a slower, reaction between PdCl 42- and o-phthalate ion. Our findings lend support to the idea that similar binding sites on fulvic acid may be capable of complexing and solubilizing Pd in the natural environment. Although thermodynamic data are required to fully quantify the extent, it is concluded that simple carboxylic acid anions and/or fulvic and humic acids should be capable of significantly enhancing Pd transport in the surficial environment by forming truly dissolved complexes. On the other hand, flocculation of fulvic/humic acids, owing to changing ionic strengths or pH, or adsorption of these acids onto mineral surfaces, may also provide effective means of immobilizing Pd. These results have applications in

  17. Quantification of the xylem-to-phloem transfer of amino acids by use of inulin (14C)carboxylic acid as xylem transfer marker

    International Nuclear Information System (INIS)

    Van Bel, A.J.

    1984-01-01

    Inulin ( 14 C)carboxylic acid and 14 C-labelled amino acid (α-aminoisobutyric acid (aib) and valine) solutions were introduced into the transpiration stream through the cut stem bases of young (4-12 leaves) tomato plants. Inulin carboxylic acid (inu) was translocated exclusively by the xylem, whereas the amino acid distribution resulted from both xylem and phloem import. Comparison of the distribution of inu and aib permitted a quantitative assessment of the xylem-to-phloem transfer in the stem. Of aib, 20.6% traversed from xylem to phloem in a plant with 12 leaves. The phloem import was not evenly distributed over the leaves and varied from 0% (first five leaves) to 95% (top leaf) of the aib import per leaf. Doubling the flow rates in the xylem reduced the aib supply to 25% in the top leaf and 55% in the next leaf, which reflects a reduced xylem-to-phloem transfer. (author)

  18. Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols and Hydroxide Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Santilli, Carola; Makarov, Ilya; Fristrup, Peter

    2016-01-01

    Primary alcohols have been reacted with hydroxide and the ruthenium complex [RuCl2(IiPr)(p-cymene)] to afford carboxylic acids and dihydrogen. The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation and extraction. The transformat......Primary alcohols have been reacted with hydroxide and the ruthenium complex [RuCl2(IiPr)(p-cymene)] to afford carboxylic acids and dihydrogen. The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation and extraction....... The transformation can be applied to a range of benzylic and saturated aliphatic alcohols containing halide and (thio)ether substituents, while olefins and ester groups are not compatible with the reaction conditions. Benzylic alcohols undergo faster conversion than other substrates, and a competing Cannizzaro...

  19. Simultaneous retention index analysis of urinary amino acids and carboxylic acids for graphic recognition of abnormal state.

    Science.gov (United States)

    Paik, Man-Jeong; Lee, Hong-Jin; Kim, Kyoung-Rae

    2005-07-05

    Simultaneous profiling analysis of urinary amino acids (AAs) and carboxylic acids (CAs) was combined with retention index (I) analysis for graphic recognition of abnormal metabolic state. The temperature-programmed I values of the AA and CA standards measured as ethoxycarbonyl (EOC)/methoxime (MO)/tert-butyldimethylsilyl (TBDMS) derivatives were used as the reference I values. Urine samples were subjected to the sequential EOC, MO and TBDMS reactions for the analysis by gas chromatography (GC) and GC-mass spectrometry. The complex GC profiles were then transformed into their respective I patterns in bar graphic forms by plotting the normalized peak area ratios (%) of the identified AAs and CAs against their reference I values as the identification numbers. When the present method was applied to infant urine specimens from normal controls and patients with inherited metabolic diseases such as phenylketonuria, maple syrup urine disease, methylmalonic aciduria or isovaleric aciduria, each I pattern of bar graph more distinctly displayed quantitative abundances of urinary AAs and CAs in qualitative I scale, thus allowing graphic discrimination between normal and abnormal states.

  20. Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake

    International Nuclear Information System (INIS)

    Motas Guzmàn, Miguel; Clementini, Chiara; Pérez-Cárceles, Maria Dolores; Jiménez Rejón, Sandra; Cascone, Aurora; Martellini, Tania; Guerranti, Cristiana; Cincinelli, Alessandra

    2016-01-01

    Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from < LOQ (< 10 ng/L) to 397 ng/L with a mean concentration of 66 ± 68 ng/L and a median of 29 ng/L. The presence of these compounds was revealed in 50 samples out of 67 analyzed. Influence of number of pregnancies and food habits on PFCAs concentrations was also investigated. Statistically significant differences in PFCA levels were found when the women were divided into maternal age classes and into the categories primiparae and multiparae. A greater transfer of PFC during breastfeeding by primiparous was evidenced and thus a higher exposure to these contaminants for the first child. Moreover, it was possible to hypothesize that the content of PFCs is in general correlated to the eating habits of donors and, in particular, with the fish consumption. Finally, PFOA daily intakes and risk index (RI) were estimated for the first six months of life and we found that ingestion rates of PFOA did not exceed the tolerable daily intake (TDI) recommended by the European Food Safety Authority (EFSA). - Graphical abstract: Figure SI 1. Concentrations (ng/L) of PFCs recovered in 67 samples of human breast milk. - Highlights: • Perfluorinated carboxylic acids were analyzed in a set of 67 breast milk samples collected from Spanish women. • PFOA appeared as the major contributor to the total perfluorinated carboxylic acids. • PFOA concentrations were significantly higher in milk of primiparous participants. • PFOA daily intake and risk index were estimated for the firsts six month of life.

  1. Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake

    Energy Technology Data Exchange (ETDEWEB)

    Motas Guzmàn, Miguel [Área de Toxicología, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Clementini, Chiara [University of Siena, Department of Physical Sciences, Earth and Environment, Via Mattioli, 4, 53100 Siena (Italy); Pérez-Cárceles, Maria Dolores; Jiménez Rejón, Sandra [Department of Legal Medicine, School of Medicine, University of Murcia & Instituto Murciano de Investigacion Biomedica (IMIB), (IMIB-VIRGEN DE LA ARRIXACA), Murcia (Spain); Cascone, Aurora; Martellini, Tania [Department of Chemistry “Ugo Schiff”, via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze (Italy); Guerranti, Cristiana [University of Siena, Department of Physical Sciences, Earth and Environment, Via Mattioli, 4, 53100 Siena (Italy); Bioscience Research Center, Via Aurelia Vecchia 32, 58015 Orbetello, GR (Italy); Cincinelli, Alessandra, E-mail: acincinelli@unifi.it [Department of Chemistry “Ugo Schiff”, via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze (Italy)

    2016-02-15

    Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from < LOQ (< 10 ng/L) to 397 ng/L with a mean concentration of 66 ± 68 ng/L and a median of 29 ng/L. The presence of these compounds was revealed in 50 samples out of 67 analyzed. Influence of number of pregnancies and food habits on PFCAs concentrations was also investigated. Statistically significant differences in PFCA levels were found when the women were divided into maternal age classes and into the categories primiparae and multiparae. A greater transfer of PFC during breastfeeding by primiparous was evidenced and thus a higher exposure to these contaminants for the first child. Moreover, it was possible to hypothesize that the content of PFCs is in general correlated to the eating habits of donors and, in particular, with the fish consumption. Finally, PFOA daily intakes and risk index (RI) were estimated for the first six months of life and we found that ingestion rates of PFOA did not exceed the tolerable daily intake (TDI) recommended by the European Food Safety Authority (EFSA). - Graphical abstract: Figure SI 1. Concentrations (ng/L) of PFCs recovered in 67 samples of human breast milk. - Highlights: • Perfluorinated carboxylic acids were analyzed in a set of 67 breast milk samples collected from Spanish women. • PFOA appeared as the major contributor to the total perfluorinated carboxylic acids. • PFOA concentrations were significantly higher in milk of primiparous participants. • PFOA daily intake and risk index were estimated for the firsts six month of life.

  2. Syntheses, structures, photoluminescence and photocatalysis of 2D layered lanthanide-carboxylates with 2, 2′-dithiodibenzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ling; Zhong, Jie-Cen; Qiu, Xing-Tai; Sun, Yan-Qiong, E-mail: sunyq@fzu.edu.cn; Chen, Yi-Ping

    2017-02-15

    Two series of lanthanide-carboxylates, [Ln(2,2′-dtba)(2,2′-Hdtba)(EtOH)]{sub n} (I:Ln=Eu(1a), Dy(1b)) and [Ln(2,2′-dtba)(2,2′-Hdtba)(4,4′-bpy){sub 0.5}]{sub n} (II:Ln=Eu(2a), Dy(2b), Tb(2c) 2,2′-H{sub 2}dtba=2,2′-dithiodibenzoic acid, 4,4′-bpy=4,4′-bipyridine) have been synthesized under hydrothermal conditions. Interestingly, the H{sub 2}dtba organic ligand was generated by in situ S–S reaction of 2-mercaptobenzoic acid. Compounds I and II possess different 2D layered structures based on similar 1D [Ln(2,2′-dtba)]{sup +} chains. Photoluminescence studies reveal that compounds I and II exhibit strong lanthanide characteristic emission bands. Remarkably, Compounds 1b and 2a both exhibit good photocatalytic activity for degradation of Rhodamine-B (Rh-B) under the simulated sunlight irradiation. - Graphical abstract: Two series of lanthanide-carboxylates have been in situ synthesized under hydrothermal conditions. The lanthanide-carboxylates exhibit strong lanthanide characteristic emission bands and good photocatalytic activity for degradation of Rhodamine-B. - Highlights: • 2D layered lanthanide-carboxylates with 2,2′-dithiodibenzoic acid. • In situ S–S reaction of 2-mercaptobenzoic acid under hydrothermal condition. • The Emission spectra of I and II exhibit the characteristic transition of lanthanide ions. • Compounds 1b and 2a exhibit good photocatalytic activity for degradation of Rhodamine-B.

  3. Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides.

    Science.gov (United States)

    Chang, Chi-Hao; Chou, Chih-Ming

    2018-04-06

    This study explores a Pd-catalyzed decarboxylative Heck-type Csp 3 -Csp 2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.

  4. Discovery of novel dihydrobenzofuran cyclopropane carboxylic acid based calcium sensing receptor antagonists for the treatment of osteoporosis.

    Science.gov (United States)

    Liang, Gui-Bai; Zhou, Changyou; Huo, Xianghong; Wang, Hank; Yang, Xuelin; Huang, Shaoqiang; Wang, Haisheng; Wilkinson, Hilary; Luo, Lusong; Tang, Wei; Sutton, David; Li, Hong; Zaller, Dennis; Meinke, Peter T

    2016-08-15

    In a search for novel small molecule calcium-sensing receptor (CaSR) antagonists as oral bone anabolic agents, we discovered dihydrobenzofuran cyclopropane carboxylic acid derivatives, such as 12f (IC50=27.6nM), are highly potent calcium-sensing receptor antagonists. Studies in rats established that compound 12f stimulates parathyroid hormone (PTH) release in a fast-acting, pulsatile manner. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Synthesis of pregnane 3-carboxylic acids via Pd-catalyzed alkoxycarbonylation and their effect on NMDA receptor activity

    Czech Academy of Sciences Publication Activity Database

    Šťastná, Eva; Chodounská, Hana; Pouzar, Vladimír; Borovská, Jiřina; Vyklický ml., Ladislav

    2011-01-01

    Roč. 76, č. 9 (2011), s. 1141-1161 ISSN 0010-0765 R&D Projects: GA ČR(CZ) GA203/08/1498; GA ČR(CZ) GA309/07/0271 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : neurosteroids * carboxylic acid * alkoxycarbonylation * steroids * NMDA receptor activity Subject RIV: CC - Organic Chemistry Impact factor: 1.283, year: 2011

  6. Cofactor balance by nicotinamide nucleotide transhydrogenase (NNT) coordinates reductive carboxylation and glucose catabolism in the tricarboxylic acid (TCA) cycle.

    Science.gov (United States)

    Gameiro, Paulo A; Laviolette, Laura A; Kelleher, Joanne K; Iliopoulos, Othon; Stephanopoulos, Gregory

    2013-05-03

    Cancer and proliferating cells exhibit an increased demand for glutamine-derived carbons to support anabolic processes. In addition, reductive carboxylation of α-ketoglutarate by isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) was recently shown to be a major source of citrate synthesis from glutamine. The role of NAD(P)H/NAD(P)(+) cofactors in coordinating glucose and glutamine utilization in the tricarboxylic acid (TCA) cycle is not well understood, with the source(s) of NADPH for the reductive carboxylation reaction remaining unexplored. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial enzyme that transfers reducing equivalents from NADH to NADPH. Here, we show that knockdown of NNT inhibits the contribution of glutamine to the TCA cycle and activates glucose catabolism in SkMel5 melanoma cells. The increase in glucose oxidation partially occurred through pyruvate carboxylase and rendered NNT knockdown cells more sensitive to glucose deprivation. Importantly, knocking down NNT inhibits reductive carboxylation in SkMel5 and 786-O renal carcinoma cells. Overexpression of NNT is sufficient to stimulate glutamine oxidation and reductive carboxylation, whereas it inhibits glucose catabolism in the TCA cycle. These observations are supported by an impairment of the NAD(P)H/NAD(P)(+) ratios. Our findings underscore the role of NNT in regulating central carbon metabolism via redox balance, calling for other mechanisms that coordinate substrate preference to maintain a functional TCA cycle.

  7. The Effects of Benzofuran-2-Carboxylic Acid Derivatives as Countermeasures in Immune Modulation and Cancer Cell Inhibition

    Science.gov (United States)

    Sundaresan, A.; Marriott, K.; Mao, J.; Bhuiyan, S.; Denkins, P.

    2015-06-01

    Microgravity and radiation exposure experienced during space flights result in immune system suppression. In long-term spaceflight, the crew is exposed to space radiation, microgravity, infectious agents from other crew members, and microbial contamination, all of which have a significant impact on the body's immune system and may contribute to the development of autoimmune diseases, allergic reactions, and/or cancer initiation. Many studies have revealed strong effects of microgravity on immune cell function, and microgravity is now considered as one of the major causes of immune dysfunction during space flight (Sundaresan, Int. J. Transp. Phenom. 12(1-2), 93-100, 2011; Martinelli et al., IEEE Eng. Biol. Med. 28(4), 85-90, 2009). We screened two newly synthetized derivatives of benzofuran 2-carboxylic acid, KMEG and KM12. The former KMEG was assessed for lymphoproliferative activities while the latter, KM12, was used in an array of cancer cell lines for testing its cancer inhibiting effects. For ground-based studies, synthetic benzofuran-2-carboxylic acid derivatives were assessed for biological effects in several scenarios, which involved exposure to modeled microgravity and radiation, as well as their immune enhancement and anti-cancer effects. Initial findings indicate that the benzofuran-2-carboxylic acid derivatives possibly have immune enhancing and anti-tumor properties in human lymphocytes and cancer cells exposed to analog spaceflight conditions modeled microgravity and γ-radiation).

  8. Developmental Toxicity of (4S-2- (4-hydroxy-3-methoxyphenyl thiazolidine-4-carboxylic acid in Zebrafish ( Danio rerio

    Directory of Open Access Journals (Sweden)

    Cansu Akbulut

    2017-08-01

    Full Text Available ABSTRACT (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid is new synthesized substance obtained from cysteine and valine. Thiazolidine derivates have important biological responses so scientists work intensively on these compounds in recent years. It is obvious that thiazolidine contained compounds will be used in future in the pharmaceutical industry to treat important diseases. Median lethal concentrations (LC50 for 48 h and 96 h were found as 1.106±0.052 mM and 0.804mM ± 0.102 respectively. According to LC50, exposure doses were determined as control, 0.4 mM, 0.2 mM and 0.1 mM (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid. Developmental toxicity and apoptotic features on zebrafish development were evaluated in this study. The results of this study indicate that (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid exposure cause developmental defects like pericardial edema, bent spine, tail malformation, blood accumulation, yolk sac edema but on the other hand concentration-dependent decrease in apoptotic rate. Likewise, concentration-dependent decrease in hatching and increase in mortality of embryos were also detected.

  9. Hydrogen-bonding interactions in thiosemicarbazones of carboxylic acids: Structure of 2-ketobutyric acid thiosemicarbazone hemihydrate

    International Nuclear Information System (INIS)

    Sonawane, P.; Chikate, R.; Kumbhar, A.; Padhye, S.; Doedens, R.J.

    1991-01-01

    2-Thiosemicarbazonobutanoic acid hemihydrate, C 5 H 9 N 3 O 2 S.0.5H 2 O, M r =184.22, triclinic, Panti 1, a=8.163(2), b=8.868(2), c=12.438(2) A, α=72.99(2), β=79.47(2), γ=84.06(2)deg, V=845.3(3) A 3 , Z=4, D x =1.447 Mg m -3 , λ(Mo Kα)=0.71073 A, μ=0.332 mm -1 , F(000)=392, T=296 K, R=0.038 for 3830 independent reflections with I>3σ(I). Three hydrogen bonds link the two crystallographically independent molecules in a pairwise fashion. The two molecules both have E configurations about each C-N and N-N bond, but differ by nearly 180deg in the orientation of the -COOH group. (orig.)

  10. Changes of sour taste and the composition of carboxylic acids induced in brewed coffee by γ-irradiation on green beans and storage of roast beans

    International Nuclear Information System (INIS)

    Tomoda, Goro; Matsuyama, Jun; Nagano, Akiko; Namatame, Mitsuko; Morita, Yoshiaki.

    1980-01-01

    Brazil santos green coffee beans were irradiated with 60 Co-γ rays at doses of 0, 0.05, 0.5 and 1.5 Mrad respectively and changes of the composition of carboxylic acids in roast beans were analyzed by means of GLC together with those of the organoleptic properties of roast beans during storage by use of the cup testing. The total acid content immediately after roasting was about 6,000 mg/100 g (roast beans) and the composition of carboxylic acids was as follows. Chlorogenic acid: hydroxy-carboxylic acids: mono-carboxylic acid: others = 73 : 18 : 7 : 2. Fresh coffee flavour was influenced markedly especially in acid taste by both irradiation of γ-rays on green beans and storage of roast beans, because of the change of above acids composition. On γ-ray irradiation, the change of the acid composition were more clear than that of stored roast beans. Therefore, the quality of γ-irradiated coffee beans seems to be closely associated with the ratio of hydroxy-carboxylic acids mg/ monocarboxylic acids mg, but little with total acid content. (author)

  11. [14C]-radiolabeling of {[trans-(8β)]-6-methyl-1-(1-methylethyl) ergoline-8-carboxylic acid, 4-methoxycyclohexyl ester (Z)-2-buteneidioate (1:1)}

    International Nuclear Information System (INIS)

    Marzoni, G.; Wheeler, W.J.; Garbrecht, W.L.

    1988-01-01

    The 5HT 2 -receptor antagonist, [ 14 C]-labeled brace[trans-(8β)]-6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid, 4-methoxycyclohexyl ester (Z)-2-butenedioate (1:1)brace (LY281067) was synthesized from unlabeled 6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid. The [ 14 C] label was introduced into the carboxyl group attached to the 8 position of the ergoline nucleus. This site is stable to metabolism. The synthesis involves removal of an unlabeled carboxyl group and subsequent reinsertion of a [ 14 C]-labeled carboxyl group into the same position. The radiolabel is not introduced until near the end of the synthesis which allows for ease of handling and scale-up of intermediates. (author)

  12. Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures.

    Science.gov (United States)

    Lego, Denise; Plaumann, Markus; Trantzschel, Thomas; Bargon, Joachim; Scheich, Henning; Buntkowsky, Gerd; Gutmann, Torsten; Sauer, Grit; Bernarding, Johannes; Bommerich, Ute

    2014-07-01

    Parahydrogen-induced polarization (PHIP) is a promising new tool for medical applications of MR, including MRI. The PHIP technique can be used to transfer high non-Boltzmann polarization, derived from parahydrogen, to isotopes with a low natural abundance or low gyromagnetic ratio (e.g. (13)C), thus improving the signal-to-noise ratio by several orders of magnitude. A few molecules acting as metabolic sensors have already been hyperpolarized with PHIP, but the direct hyperpolarization of drugs used to treat neurological disorders has not been accomplished until now. Here, we report on the first successful hyperpolarization of valproate (valproic acid, VPA), an important and commonly used antiepileptic drug. Hyperpolarization was confirmed by detecting the corresponding signal patterns in the (1)H NMR spectrum. To identify the optimal experimental conditions for the conversion of an appropriate VPA precursor, structurally related molecules with different side chains were analyzed in different solvents using various catalytic systems. The presented results include hyperpolarized (13)C NMR spectra and proton images of related systems, confirming their applicability for MR studies. PHIP-based polarization enhancement may provide a new MR technique to monitor the spatial distribution of valproate in brain tissue and to analyze metabolic pathways after valproate administration. Copyright © 2014 John Wiley & Sons, Ltd.

  13. How CO2 Interacts with Carboxylic Acids: A Rotational Study of Formic Acid-CO2.

    Science.gov (United States)

    Vigorito, Annalisa; Gou, Qian; Calabrese, Camilla; Melandri, Sonia; Maris, Assimo; Caminati, Walther

    2015-10-05

    The rotational spectra of the 1:1 formic acid-carbon dioxide molecular complex and of its monodeuterated isotopologues are analysed in the 6.5-18.5 and 59.6-74.4 GHz frequency ranges using a pulsed jet Fourier transform microwave spectrometer and a free-jet absorption millimetre wave spectrometer, respectively. Precise values of the rotational and quartic centrifugal distortion constants are obtained from the measured frequencies, and quadrupole coupling constants are determined from the deuterium hyperfine splittings. Structural parameters are estimated from the moments of inertia and their differences among isotopologues: the complex has a planar structure with the two subunits held together by a HC(O)OH⋅⋅⋅O=C=O (2.075 Å) and a HC(OH)O⋅⋅⋅CO2 (2.877 Å) interactions. The ab initio intermolecular binding energy, obtained at the counterpoise corrected MP2/aug-cc-pVTZ level of calculation, is De =17 kJ mol(-1). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Application of 2-Aminothiazoline-4-carboxylic Acid as a Forensic Marker of Cyanide Exposure.

    Science.gov (United States)

    Rużycka, Monika; Giebułtowicz, Joanna; Fudalej, Marcin; Krajewski, Paweł; Wroczyński, Piotr

    2017-02-20

    Cyanides are infamous for their highly poisonous properties. Accidental cyanide poisoning occurs frequently, but occasionally, intentional poisonings also occur. Inhalation of fumes generated by fire may also cause cyanide poisoning. There are many limitations in direct analysis of cyanide. 2-Aminothiazoline-4-carboxylic acid (ATCA), a cyanide metabolite, seems to be the only surrogate that is being used in the detection of cyanide because of its stability and its cyanide-dependent quality in a biological matrix. Unfortunately, toxicokinetic studies on diverse animal models suggest significant interspecies differences; therefore, the attempt to extrapolate animal models to human models may be unsuccessful. The aim of the present study was to evaluate the use of ATCA as a forensic marker of cyanide exposure. For this purpose, post-mortem materials (blood and organs) from fire victims (n = 32) and cyanide-poisoned persons (n = 3) were collected. The distribution of ATCA in organs and its thermal stability were evaluated. The variability of cyanides in a putrid sample and in the context of their long-term and higher temperature stability was established. The presence of ATCA was detected by using an LC-MS/MS method and that of cyanide was detected spectrofluorimetrically. This is the first report on the endogenous ATCA concentrations and the determination of ATCA distribution in tissues of fire victims and cyanide-poisoned persons. It was found that blood and heart had the highest ATCA concentrations. ATCA was observed to be thermally stable even at 90 °C. Even though the cyanide concentration was not elevated in putrid samples, it was unstable during long-term storage and at higher temperature, as expected. The relationship between ATCA and cyanides was also observed. Higher ATCA concentrations were related to increased levels of cyanide in blood and organs (less prominent). ATCA seems to be a reliable forensic marker of exposure to lethal doses of cyanide.

  15. Pre-staining thin layer chromatography method for amino acid ...

    African Journals Online (AJOL)

    The modified thin layer chromatography can be used for the analysis of amino acids. When compared to the classical thin layer chromatography, the improved method was more rapid and inexpensive and the results obtained were clean and reproducible. However, it is suitable for the high throughput screening of amino ...

  16. ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC

    Science.gov (United States)

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular structure. The energy diffe...

  17. Synthesis of new oxovanadium (IV) complexes of potential insulinmimetic activity with coumarin-3-carboxylic acid ligands and substituted derivatives

    International Nuclear Information System (INIS)

    Salas Fernandez, Paloma; Alvino de la Sota, Nora; Galli Rigo-Righi, Carla

    2013-01-01

    This work comprises the design and synthesis of four new oxovanadium (IV) complexes, a metal which possesses insulin-mimetic action. Coumarin-3-carboxylic acid and three of its 6 -and 6,8- derivatives were used as ligands. Coumarins are of interest due to their well-known biological properties and pharmacological applications; these include the insulino-sensibilizing effect of certain alcoxy-hydroxy-derivatives which might lead to the eventual existence of a synergetic effect with the active metal center. The synthesis of the vanadyl complexes was preceded by the synthesis of the coumarin-3-carboxylic acid and its 6-bromo- derivative, as well as the syntheses of three derivatives not previously reported: 6-bromo-8-metoxi-, 6-bromo-8-nitro-, and 6-bromo-8-hydroxy-, which were prepared by a Knoevenagel condensation reaction. The complexes, on their part, were prepared by a metathesis reaction between VOSO 4 and the corresponding ligands, on the basis of methods reported for other vanadyl complexes and under strict pH control. The coumarin-3-carboxylic ligands and the derivatives were characterized by 1 H-NMR-, FTIR- and UV-Vis-spectroscopy. In the case of the complexes, their paramagnetic character did not allow for NMR characterization, being thus identified by FT-IR-spectroscopy and by the quantitative determination of their vanadium contents. (author)

  18. Carboxylic Acid-Functionalized Conducting-Polymer Nanotubes as Highly Sensitive Nerve-Agent Chemiresistors

    Science.gov (United States)

    Kwon, Oh Seok; Park, Chul Soon; Park, Seon Joo; Noh, Seonmyeong; Kim, Saerona; Kong, Hye Jeong; Bae, Joonwon; Lee, Chang-Soo; Yoon, Hyeonseok

    2016-09-01

    Organophosphates are powerful inhibitors of acetylcholinesterase, which is critical to nerve function. Despite continuous research for detecting the highly toxic organophosphates, a new and improved methodology is still needed. Herein we demonstrate simple-to-fabricate chemiresistive gas sensors using conducting-polymer polypyrrole (PPy) nanotube transducers, which are chemically specific and capable of recognizing sub-ppb concentrations (ca. 0.5 ppb) of dimethyl methylphosphonate (DMMP), a simulant of nerve agent sarin. Interestingly, the introduction of carboxylic groups on the surface of PPy nanotube transistors resulted in enhanced sensitivity to DMMP via intermolecular hydrogen bonding. Furthermore, it was found that the sensitivity of the nanotube transducer depended on the degree of the carboxylic group introduced. Finally, a sensor array composed of 5 different transducers including the carboxylated nanotubes exhibited excellent selectivity to DMMP in 16 vapor species.

  19. Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene

    International Nuclear Information System (INIS)

    Souane, R.

    2005-03-01

    In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO 2 2+ form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO 2 ) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO 2 L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid (ΔlogΒ110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO 2 2+ . This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23. (author)

  20. Formation and High-order Carboxylic Acids (RCOOH) in Interstellar Analogous Ices of Carbon Dioxide (CO2) and Methane(CH4)

    Science.gov (United States)

    Zhu, Cheng; Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2018-01-01

    This laboratory study simulated the abiotic formation of carboxylic acids (RCOOH) in interstellar analogous ices of carbon dioxide (CO2) and methane (CH4) at 10 K upon exposure to energetic electrons. The chemical processing of the ices and the subsequent warm-up phase were monitored online and in situ, exploiting Fourier Transform Infrared Spectrometry and quadrupole mass spectrometry. Characteristic absorptions of functional groups of carboxylic acids (RCOOH) were observed in the infrared spectra of the irradiated ice. Two proposed reaction mechanisms replicated the kinetic profiles of the carboxylic acids along with the decay profile of the precursors during the irradiation via hydrocarbon formation, followed by carboxylation and/or through acetic acid along with mass growth processes of the alkyl chain. Mass spectra recorded during the warm-up phase demonstrated that these acids are distributed from acetic acid (CH3COOH) up to decanoic acid (C9H19COOH). High-dose irradiation studies (91 ± 14 eV) converted low-molecular-weight acids such as acetic acid (CH3COOH) and propionic acid (C2H5COOH) to higher-molecular-weight carboxylic acids, compared to low-dose irradiation studies (18 ± 3 eV). The traces of the {{{H}}}2{{C}}= {{C}}({OH}{)}2+ (m/z = 60) fragment—a link to linear carboxylic acids—implied that higher-order acids (C n H2n+1COOH, n ≥ 5) are likely branched, which correlates with the recent analysis of the structures of the monocarboxylic acids in the Murchison meteorite.

  1. Rapid Screening of Carboxylic Acids from Waste and Surface Waters by ESI-MS/MS Using Barium Ion Chemistry and On-Line Membrane Sampling.

    Science.gov (United States)

    Duncan, Kyle D; Volmer, Dietrich A; Gill, Chris G; Krogh, Erik T

    2016-03-01

    Negative ion tandem mass spectrometric analysis of aliphatic carboxylic acids often yields only non-diagnostic ([M - H](-)) ions with limited selective fragmentation. However, carboxylates cationized with Ba(2+) have demonstrated efficient dissociation in positive ion mode, providing structurally diagnostic product ions. We report the application of barium adducts followed by collision induced dissociation (CID), to improve selectivity for rapid screening of carboxylic acids in complex aqueous samples. The quantitative MS/MS method presented utilizes common product ions of [M - H + Ba](+) precursor ions. The mechanism of product ion formation is investigated using isotopically labeled standards and a series of structurally related carboxylic acids. The results suggest that hydrogen atoms in the β and γ positions yield common product ions ([BaH](+) and [BaOH](+)). Furthermore, the diagnostic product ion at m/z 196 serves as a qualifying ion for carboxylate species. This methodology has been successfully used in conjunction with condensed phase membrane introduction mass spectrometry (CP-MIMS), with barium acetate added directly to the methanol acceptor phase. The combination enables rapid screening of carboxylic acids directly from acidified water samples (wastewater effluent, spiked natural waters) using a capillary hollow fiber PDMS membrane immersion probe. We have applied this technique for the direct analysis of complex naphthenic acid mixtures spiked into natural surface waters using CP-MIMS. Selectivity at the ionization and tandem mass spectrometry level eliminate isobaric interferences from hydroxylated species present within the samples, which have been observed in negative electrospray ionization.

  2. Elimination of inhibiting action of p-methylcyclohexane carboxylic acid on electrode processes in alternating-current polarography

    International Nuclear Information System (INIS)

    Dzhafarova, T.A.; Zhdanov, S.I.; Niyazov, A.N.; Dzumaev, R.M.

    1978-01-01

    By the method of alternating-current polarography studied is the inhibiting action of p-methylcyclohexane carboxylic acid on electrode processes of Cu, Pb, Cd and Zn reduction and its elimination by iodide ions. It is shown that acid prevents from Pd and Cd ion reduction at mercury-dropping electrode; the more close is the ion reduction potential to the maximum acid adsorption potential and the more is its concentration in the solution, the stronger prevention is. Iodide ions introduction in the solution leads to the acceleration of inhibited processes with the shift of the reduction potentials in the negative region. The less I quantity is necessary to accelerate the electrode process, the more close its potential is to the I adsorption potential. It is assumed that activating effect of iodide ions is caused by the decrease of the degree of electrode surface filling by acid molecules in the result of competition adsorption with I

  3. Production of the Antibiotic Phenazine-1-Carboxylic Acid by Fluorescent Pseudomonas Species in the Rhizosphere of Wheat

    OpenAIRE

    Thomashow, Linda S.; Weller, David M.; Bonsall, Robert F.; Pierson, Leland S.

    1990-01-01

    Pseudomonas fluorescens 2-79 and P. aureofaciens 30-84 produce the antibiotic phenazine-1-carboxylic acid and suppress take-all, an important root disease of wheat caused by Gaeumannomyces graminis var. tritici. To determine whether the antibiotic is produced in situ, wheat seeds were treated with strain 2-79 or 30-84 or with phenazine-nonproducing mutants or were left untreated and then were sown in natural or steamed soil in the field or growth chamber. The antibiotic was isolated only from...

  4. Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110)

    International Nuclear Information System (INIS)

    Song Fei; Mao Hongying; Guan Dandan; Dou Weidong; Zhang Hanjie; Li Haiyang; He Pimo; Bao Shining; Hofmann, Philip

    2009-01-01

    The interface electronic properties of fluorene-1-carboxylic acid (FC-1) adsorbed on Cu(110) have been studied by ultraviolet photoemission spectroscopy (UPS) and first-principles calculations. Both the molecular orbitals and the Cu valence band are significantly modified upon adsorption. FC-1 is chemically bonded to Cu(110) through charge donation and back donation involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the molecule. An observed reduction of the work function can be attributed to the adsorption induced charge redistribution, and the positive interface dipole.

  5. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    Science.gov (United States)

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)). Copyright © 2012 Elsevier B.V. All rights reserved.

  6. The effect of dietary fiber from wheat processing streams on the formation of carboxylic acids and microbiota in the hindgut of rats.

    Science.gov (United States)

    Haskå, Lina; Andersson, Roger; Nyman, Margareta

    2011-04-13

    Colonic fermentation of dietary fiber produces carboxylic acids and may stimulate the growth of beneficial bacteria. This study investigated how byproducts of wheat processing (distillers' grains and two fractions from the wet fractionation to starch and gluten, one of which was treated with xylanase) affect the composition of the cecal microbiota and the formation of carboxylic acids in rats. Differences were mostly found between diets based on supernatants and pellets, rather than between fiber sources. Cecal pools and levels of most carboxylic acids in portal blood were higher for rats fed the supernatant diets, while cecal pH and ratios of acetic to propionic acid in portal blood were lower. The diet based on supernatant from distillers' grains gave the highest level of bifidobacteria. Molecular weight and solubility are easier to modify with technological processes, which provides an opportunity to optimize these properties in the development of health products.

  7. The influence of the substrate structure in the telluro-cyclo-functionalization reaction of {gamma}, {delta}-unsaturated carboxylic acids and their corresponding benzyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Denilson N.; Santos, Rute A.; Comasseto, Joao V. [Sao Paulo Univ., SP (Brazil). Inst. de Quimica

    1998-07-01

    {gamma},{delta}-Unsaturated carboxylic acids containing mono substituted double bonds react with aryl tellurium trichlorides to give the expected telluro lactone. Reaction of the corresponding benzyl esters gives the addition product of the aryl tellurium trichlorides to the double bond {gamma}, {delta}-Unsaturated carboxylic acids containing 1,1-disubstituted double bonds lead to a mixture of the expected telluro lactone and the product of hydrochloric acid addition to the double bond; the corresponding benzyl ester gives the telluro lactone as the only product. The stereoselectivity of the reaction is low; mixtures of the two possible diastereomeric lactones are formed in approximately 1:1 ratios. (author)

  8. Investigation of the role of aromatic carboxylic acids in cross-linking processes in low-rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Eskay, T.P.; Britt, P.F.; Buchanan, A.C. III

    1997-03-01

    In the pyrolysis and liquefaction of low-rank coals, low-temperature cross-linking reactions have been correlated with the loss of carboxyl groups and the evolution of CO{sub 2} and H{sub 2}O. It is not clearly understood how decarboxylation leads to cross-linking beyond the suggestion that decarboxylation could be a radical process that involves radical recombination or radical addition reactions. We have recently conducted a study of the pyrolysis of 1,2-(3,3{prime}-dicarboxyphenyl)ethane (1) and 1,2-(4,4{prime}-dicarboxyphenyl)ethane (2) and found that decarboxylation occurs readily between 350-425 {degrees}C with no evidence of coupling products or products representative of cross-links. We proposed that decarboxylation occurred primarily by an acid-promoted cationic pathway, and the source of acid was a second carboxylic acid. The decarboxylation of 1 and 2 was investigated in diphenyl ether and naphthalene as inert diluents. In each solvent, the rate of decarboxylation dropped by roughly a factor of 2 upon dilution from the neat liquid to ca. 0.4 mole fraction of acid, but further dilution had no effect on the rate. This could be a consequence of hydrogen bonding or an intramolecular protonation. Molecular mechanics calculations indicated that 1 and 2 can adopt an appropriate conformation for internal proton transfer from a carboxy group on one ring to the second aryl ring without a significant energy penalty. In addition, the dicarboxylic acid could internally hydrogen bond, which may further complicate the reaction mechanism. Therefore, we have conducted a study of the pyrolysis of a monocarboxybibenzyl, 1-(3-carboxyphenyl)-2-(4-biphenyl)ethane (3), to determine if decarboxylation occurs by an ionic pathway in the absence of intramolecular pathways.

  9. Effect of a Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A Small-angle Neutron Scattering Study

    International Nuclear Information System (INIS)

    Arum Patriati; Edy Giri Rachman Putra

    2009-01-01

    The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH 3 (CH 2 ) 10 COOH and hexadecanoic acid, CH 3 (CH 2 ) 14 COOH as a co-surfactant in the 0.3M SDS micellar solution has been studied using small angle neutron scattering (SANS). Here, the present of dodecanoic acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 21.7 Armstrong to 35.5 Armstrong at a fixed minor axis of 16.7 Armstrong in the present of 0.005M to 0.1M dodecanoic acid. Nevertheless, this effect was not shown in the present of hexadecanoic acid with the same concentration range. The present of hexadecanoic acid molecules gave a small effect on growth of SDS micelles where the major axis of the micelle was simply elongated from 21.5 Armstrong to 23.5 Armstrong. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules is one of the determining factors in forming a mixed micelles structure. (author)

  10. [Effects of overexpression of carboxylation pathway genes and inactivation of malic enzymes on malic acid production in Escherichia coli].

    Science.gov (United States)

    Lou, Fei; Li, Ning; Zhao, Yujiao; Guo, Shiting; Wang, Zhiwen; Chen, Tao

    2016-11-25

    Malic acid is a dicarboxylic acid that is widely used in food, pharmaceutical and chemical industries. We studied the effects of overexpression of carboxylation pathway genes and inactivation of malic enzymes on the aerobic production of malic acid. Over expression of phosphoenolpyruvate (PEP) carboxylase (ppc) generated strain E21, which increased malic acid production from 0.57 g/L to 3.83 g/L. Then pyc gene from Coryenbacterium glutamicus and pck gene from Actinobacillus succinogenes were overexpressed in E21 separately. The resulting strains E21 (pTrcpyc) and E21 (pTrc-A-pck) produced 6.04 and 5.01 g/L malate with a yield of 0.79 and 0.65 mol/mol glucose, respectively. Deleting two malic enzymes (encoded by maeA and maeB) also led to an increase of 36% in malic acid production with a production of 5.21 g/L. However, the combination of malic enzymes deletion and pyc overexpression could not further increase the yield of malic acid. After optimization of fermentation conditions, strain E21 (pTrcpyc) produced 12.45 g/L malic acid with a yield of 0.84 mol/mol which is 63.2% of the theoretical yield.

  11. Benzene-poly-carboxylic acid complex, a novel anti-cancer agent induces apoptosis in human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Fuad Fares

    Full Text Available Some cases of breast cancer are composed of clones of hormonal-independent growing cells, which do not respond to therapy. In the present study, the effect of Benzene-Poly-Carboxylic Acid Complex (BP-C1 on growth of human breast-cancer cells was tested. BP-C1 is a novel anti-cancer complex of benzene-poly-carboxylic acids with a very low concentration of cis-diammineplatinum (II dichloride. Human breast cancer cells, MCF-7 and T47D, were used. Cell viability was detected by XTT assay and apoptosis was detected by Flow Cytometry and by annexin V/FITC/PI assay. Caspases were detected by western blot analysis and gene expression was measured by using the Applied Biosystems® TaqMan® Array Plates. The results showed that exposure of the cells to BP-C1 for 48 h, significantly (P<0.001 reduced cell viability, induced apoptosis and activated caspase 8 and caspace 9. Moreover, gene expression experiments indicated that BP-C1 increased the expression of pro-apoptotic genes (CASP8AP1, TNFRSF21, NFkB2, FADD, BCL10 and CASP8 and lowered the level of mRNA transcripts of inhibitory apoptotic genes (BCL2L11, BCL2L2 and XIAP. These findings may lead to the development of new therapeutic strategies for treatment of human cancer using BP-C1 analog.

  12. Synthesis and bioevaluation of 2-phenyl-4-methyl-1,3-selenazole-5-carboxylic acids as potent xanthine oxidase inhibitors.

    Science.gov (United States)

    Guan, Qi; Cheng, Zengjin; Ma, Xiaoxue; Wang, Lijie; Feng, Dongjie; Cui, Yuanhang; Bao, Kai; Wu, Lan; Zhang, Weige

    2014-10-06

    A series of 2-phenyl-4-methyl-1,3-selenazole-5-carboxylic acid derivatives (8a-f, 9a-m) were synthesized and evaluated for inhibitory activity against xanthine oxidase in vitro. Structure-activity relationship analyses have also been presented. Most of the target compounds exhibited potency levels in the nanomolar range. Compound 9e emerged as the most potent xanthine oxidase inhibitor (IC50 = 5.5 nM) in comparison to febuxostat (IC50 = 18.6 nM). Steady-state kinetics measurements with the bovine milk enzyme indicated a mixed type inhibition with Ki and Ki' values of 0.9 and 2.3 nM, respectively. A molecular modeling study on compounds 9e was performed to gain an insight into its binding mode with xanthine oxidase, and to provide the basis for further structure-guided design of new non-purine xanthine oxidase inhibitors related with 2-phenyl-4-methyl-1,3-selenazole-5-carboxylic acid scaffold. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Isolation and Identification of Two l-Azetidine-2-carboxylic Acid-Degrading Soil Microorganisms, Enterobacter agglomerans and Enterobacter amnigenus

    Science.gov (United States)

    Yeung; Lee; Woodard

    1998-02-27

    Soil samples collected at several times during the growing season and at different locations within Convallaria majalis beds in Ann Arbor, MI, were screened for their ability to grow with the cyclic amino acid, l-azetidine-2-carboxylic acid (l-A-2-C), as their sole nitrogen source (i.e., metabolize l-A-2-C). Two different soil microorganisms were isolated, characterized, and identified using fundamental selection methods, the standard battery of biochemical characterization tests, and scanning electron microscopy. The assignment of the identity of these organisms as Enterobacter agglomerans and Enterobacter amnigenus was further verified by comparison with authentic microbial samples obtained from ATCC that were able to utilize l-A-2-C as their sole nitrogen source.

  14. Zeolite-catalysed preparation of alpha-hydroxy carboxylic acids and esters thereof

    OpenAIRE

    Taarning, Esben; Shunmugavel, Saravanamurugan; Holm, Martin Spangsberg

    2010-01-01

    A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.

  15. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    Science.gov (United States)

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  16. Infrared study of some 2-substituted-6-hydroxy-4-pyrimidine carboxylic acids. Correlation with MO-calculations

    Directory of Open Access Journals (Sweden)

    IVAN O. JURANIC

    2000-06-01

    Full Text Available The IR spectra of a series of 2-substituted-6-hydroxy-4-pyrimidine carboxylic acids (substituent = OH, SH, CH3, CH3S and NH2 were studied from the aspect of the influence of the subsitutent on the polarizability of some bonds, keto-enol tautomerism and hydrogen bond formation. The spectra were taken using solids due to the low solubility of the acids. Theoretical calculations were done using the MNDO-AM1 semiempirical molecular-orbital method. The stabilities of various tautomers were calculated simulating the dielectric continuum using the COSMO facility of the MOPAC program package. Theoretical calculations were made for all the possible tautomers of the 2-substituted-6-hydroxy-4-pyrimidine carboxylic acids. For the most stable isomers, the vibrational spectra were calculated. For the majority of the compounds the most stable isomer was identified having the structure 2-Y-6-oxo-4-carboxy-3H-pyrimidine. Besides this structure, for the 2-amino-, and 2-methyl- derivatives the zwitterionic forms have very similar stability. The 2-hydroxy compound is most stable as the 2,6-dioxo-1H, 3H isomer. The calculated vibrations for the compounds with a single stable structure correlate very well with the experimental frequencies. For the 2-methyl- and 2-amino- compounds the correlation is considerably less satisfactory. The most probable reason for this deviation is the existence of two or more tautomets in equilibrium. The correlation of the measured frequencies and the pKa values of the acids, indicate that the same tautomers exist in the solid state and in the solution.

  17. Zeolite-catalysed preparation of alpha-hydroxy carboxylic acids and esters thereof

    DEFF Research Database (Denmark)

    2010-01-01

    A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.......A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst....

  18. Double Hydrogen Bonding between Side Chain Carboxyl Groups in Aqueous Solutions of Poly (β-L-Malic Acid): Implication for the Evolutionary Origin of Nucleic Acids

    Science.gov (United States)

    Francis, Brian R.; Watkins, Kevin; Kubelka, Jan

    2017-01-01

    The RNA world hypothesis holds that in the evolutionary events that led to the emergence of life RNA preceded proteins and DNA and is supported by the ability of RNA to act as both a genetic polymer and a catalyst. On the other hand, biosynthesis of nucleic acids requires a large number of enzymes and chemical synthesis of RNA under presumed prebiotic conditions is complicated and requires many sequential steps. These observations suggest that biosynthesis of RNA is the end product of a long evolutionary process. If so, what was the original polymer from which RNA and DNA evolved? In most syntheses of simpler RNA or DNA analogs, the D-ribose phosphate polymer backbone is altered and the purine and pyrimidine bases are retained for hydrogen bonding between complementary base pairs. However, the bases are themselves products of complex biosynthetic pathways and hence they too may have evolved from simpler polymer side chains that had the ability to form hydrogen bonds. We hypothesize that the earliest evolutionary predecessor of nucleic acids was the simple linear polyester, poly (β-D-malic acid), for which the carboxyl side chains could form double hydrogen bonds. In this study, we show that in accord with this hypothesis a closely related polyester, poly (β-L-malic acid), uses carboxyl side chains to form robust intramolecular double hydrogen bonds in moderately acidic solution. PMID:29061955

  19. Design of co-crystals/salts of some Nitrogenous bases and some derivatives of thiophene carboxylic acids through a combination of hydrogen and halogen bonds.

    Science.gov (United States)

    Jennifer, Samson Jegan; Muthiah, Packianathan Thomas

    2014-01-01

    The utility of N-heterocyclic bases to obtain molecular complexes with carboxylic acids is well studied. Depending on the solid state interaction between the N-heterocyclic base and a carboxylic acid a variety of neutral or ionic synthons are observed. Meanwhile, pyridines and pyrimidines have been frequently chosen in the area of crystal engineering for their multipurpose functionality. HT (hetero trimers) and LHT (linear heterotetramers) are the well known synthons that are formed in the presence of pyrimidines and carboxylic acids. Fourteen crystals involving various substituted thiophene carboxylic acid derivatives and nitrogenous bases were prepared and characterized by using single crystal X-ray diffraction. The 14 crystals can further be divided into two groups [1a-7a], [8b-14b] based on the nature of the nitrogenous base. Carboxylic acid to pyridine proton transfer has occurred in 3 compounds of each group. In addition to the commonly occurring hydrogen bond based pyridine/carboxylic acid and pyrimidine/carboxylic acid synthons which is the reason for assembly of primary motifs, various other interactions like Cl…Cl, Cl…O, C-H…Cl, C-H…S add additional support in organizing these supermolecules into extended architectures. It is also interesting to note that in all the compounds π-π stacking occurs between the pyrimidine-pyrimidine or pyridine-pyridine or acid-acid moieties rather than acid-pyrimidine/pyridine. In all the compounds (1a-14b) either neutral O-H…Npyridyl/pyrimidine or charge-assisted Npyridinium-H…Ocarboxylate hydrogen bonds are present. The HT (hetero trimers) and LHT (linear heterotetramers) are dominant in the crystal structures of the adducts containing N-heterocyclic bases with two proton acceptors (1a-7a). Similar type supramolecular ladders are observed in 5TPC44BIPY (8b), TPC44BIPY (9b), TPC44TMBP (11b). Among the seven compounds [8b-14b] the extended ligands are linear in all except for the TMBP (10b, 11b, 12b). The

  20. Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene--divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi

    2003-05-16

    The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent.

  1. Determination of ferulic acid and related compounds by thin layer ...

    African Journals Online (AJOL)

    The analysis of certain phenolic compounds from plants, and their chemical transformation with microorganisms or isolated enzymes, has application in the food and pharmaceutical industry. The rapid quantitative estimation of ferulic acid by thin layer chromatography is described by measurement of the area of the ...

  2. Comparison of CO2 and oxygen DC submerged thermal plasmas for decomposition of carboxylic acid in aqueous solution

    Science.gov (United States)

    Safa, S.; Hekmat-Ardakan, A.; Soucy, G.

    2014-11-01

    The feasibility of the carboxylic acid decomposition with two different direct current (DC) thermal plasma torches was investigated. An oxygen DC submerged thermal plasma torch and a newly designed submerged DC plasma torch operating with a mixture of carbon dioxide and methane (CO2/CH4) were used. Sebacic acid was selected as a representative of pollutants in the most wastewater produced by chemical process industries. The effect of different operational conditions including treatment time, the reactor pressure as well as the role of oxidizing agents such as (H2O2) were investigated on the decomposition rate of sebacic acid. Concentration of sebacic acid was quantified by Ion Chromatography/Mass Spectrometry (IC/MS). The oxygen plasma showed higher decomposition rate in basic medium. Adding H2O2 into aqueous solution enhanced the sebacic acid decomposition rate with the CO2/CH4 plasma up to the same decomposition rate of the oxygen plasma. Increasing the pressure also increased the decomposition rate for both plasmas with an increase twice higher for the CO2/CH4 plasma than that of the oxygen plasma. This work therefore presents the conditions in which these plasmas can provide the same decomposition rate for contaminants in aqueous solution.

  3. Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

    International Nuclear Information System (INIS)

    Akal, Z.Ü.; Alpsoy, L.; Baykal, A.

    2016-01-01

    Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

  4. Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Akal, Z.Ü., E-mail: zulker@fatih.edu.tr [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Alpsoy, L. [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Department of Medical Biology, 34500 Büyükçekmece, Istanbul (Turkey); Baykal, A. [Department of Chemistry, Fatih University, 34500 Büyükçekmece, Istanbul (Turkey)

    2016-08-15

    Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

  5. Do carboximide–carboxylic acid combinations form co-crystals? The role of hydroxyl substitution on the formation of co-crystals and eutectics

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2015-05-01

    Full Text Available Carboxylic acids, amides and imides are key organic systems which provide understanding of molecular recognition and binding phenomena important in biological and pharmaceutical settings. In this context, studies of their mutual interactions and compatibility through co-crystallization may pave the way for greater understanding and new applications of their combinations. Extensive co-crystallization studies are available for carboxylic acid/amide combinations, but only a few examples of carboxylic acid/imide co-crystals are currently observed in the literature. The non-formation of co-crystals for carboxylic acid/imide combinations has previously been rationalized, based on steric and computed stability factors. In the light of the growing awareness of eutectic mixtures as an alternative outcome in co-crystallization experiments, the nature of various benzoic acid/cyclic imide combinations is established in this paper. Since an additional functional group can provide sites for new intermolecular interactions and, potentially, promote supramolecular growth into a co-crystal, benzoic acids decorated with one or more hydroxyl groups have been systematically screened for co-crystallization with one unsaturated and two saturated cyclic imides. The facile formation of an abundant number of hydroxybenzoic acid/cyclic carboximide co-crystals is reported, including polymorphic and variable stoichiometry co-crystals. In the cases where co-crystals did not form, the combinations are shown invariably to result in eutectics. The presence or absence and geometric disposition of hydroxyl functionality on benzoic acid is thus found to drive the formation of co-crystals or eutectics for the studied carboxylic acid/imide combinations.

  6. Do carboximide-carboxylic acid combinations form co-crystals? The role of hydroxyl substitution on the formation of co-crystals and eutectics.

    Science.gov (United States)

    Kaur, Ramanpreet; Gautam, Raj; Cherukuvada, Suryanarayan; Guru Row, Tayur N

    2015-05-01

    Carboxylic acids, amides and imides are key organic systems which provide understanding of molecular recognition and binding phenomena important in biological and pharmaceutical settings. In this context, studies of their mutual interactions and compatibility through co-crystallization may pave the way for greater understanding and new applications of their combinations. Extensive co-crystallization studies are available for carboxylic acid/amide combinations, but only a few examples of carboxylic acid/imide co-crystals are currently observed in the literature. The non-formation of co-crystals for carboxylic acid/imide combinations has previously been rationalized, based on steric and computed stability factors. In the light of the growing awareness of eutectic mixtures as an alternative outcome in co-crystallization experiments, the nature of various benzoic acid/cyclic imide combinations is established in this paper. Since an additional functional group can provide sites for new intermolecular inter-actions and, potentially, promote supramolecular growth into a co-crystal, benzoic acids decorated with one or more hydroxyl groups have been systematically screened for co-crystallization with one unsaturated and two saturated cyclic imides. The facile formation of an abundant number of hydroxybenzoic acid/cyclic carboximide co-crystals is reported, including polymorphic and variable stoichiometry co-crystals. In the cases where co-crystals did not form, the combinations are shown invariably to result in eutectics. The presence or absence and geometric disposition of hydroxyl functionality on benzoic acid is thus found to drive the formation of co-crystals or eutectics for the studied carboxylic acid/imide combinations.

  7. Influence of carboxylic acid type on microstructure and magnetic properties of polymeric complex sol–gel driven NiFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Hessien, M.M. [Materials Science & Engineering Group, Department of Chemistry, Faculty of Science, Taif University (Saudi Arabia); Advanced Materials Dept, Central Metallurgical Research and Development Institute (CMRDI), P.O. Box: 87, Helwan, Cairo (Egypt); Mostafa, Nasser Y., E-mail: nmost69@yahoo.com [Materials Science & Engineering Group, Department of Chemistry, Faculty of Science, Taif University (Saudi Arabia); Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia (Egypt); Abd-Elkader, Omar H. [Department of Zoology, Science College, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Electron Microscope and Thin Films Department, National Research Center (NRC), El-Behooth Street, Dokki, Cairo 12622 (Egypt)

    2016-01-15

    Citric, oxalic and tartaric acids were used for synthesis of NiFe{sub 2}O{sub 4} using polymeric complex precursor route. The dry precursor gels were calcined at various temperatures (400–1100 °C) for 2 h. All carboxylic acids produce iron-deficient NiFe{sub 2}O{sub 4} with considerable amount of α-Fe{sub 2}O{sub 3} at 400 °C. Increase in the annealing temperature caused reaction of α-Fe{sub 2}O{sub 3} with iron-deficient ferrite phase. The amount of initially formed α-Fe{sub 2}O{sub 3} is directly correlated with stability constant and inversely correlated with the decomposition temperature of Fe(III) carboxylate precursors. In case of tartaric acid precursor, single phase of the ferrite was obtained at 450 °C. However, in case of oxalic acid and citric acid precursors, single phase ferrite was obtained at 550 °C and 700 °C, respectively. The lattice parameters were increased with increasing annealing temperature and with decreasing the amount of α-Fe{sub 2}O{sub 3}. Maximum saturation magnetization (55 emu/g) was achieved using tartaric acid precursor annealed at 1100 °C. - Highlights: • Citric, oxalic and tartaric acids were used for synthesis of NiFe{sub 2}O{sub 4}. • Carboxylic acid type affects the produced powders. • At low temperatures all carboxylic acids produce iron-deficient NiFe{sub 2}O{sub 4} and α-Fe{sub 2}O{sub 3}. • α-Fe{sub 2}O{sub 3} is correlated with the decomposition of Fe(III) carboxylate precursors.

  8. Cloning and characterization of a benzoic acid/salicylic acid carboxyl methyltransferase gene involved in floral scent production from lily (Lilium 'Yelloween').

    Science.gov (United States)

    Wang, H; Sun, M; Li, L L; Xie, X H; Zhang, Q X

    2015-11-19

    In lily flowers, the volatile ester methyl benzoate is one of the major and abundant floral scent compounds; however, knowledge regarding the biosynthesis of methyl benzoate remains unknown for Lilium. In this study, we isolated a benzoic acid/salicylic acid carboxyl methyltransferase (BSMT) gene, LiBSMT, from petals of Lilium 'Yelloween'. The gene has an open reading frame of 1083 base pairs (bp) and encodes a protein of 41.05 kDa. Sequence alignment and phylogenetic analyses of LiBSMT revealed 40-50% similarity with other known benzenoid carboxyl methyltransferases in other plant species, and revealed homology to BSMT of Oryza sativa. Heterologous expression of this gene in Escherichia coli yielded an enzyme responsible for catalyzing benzoic acid and salicylic acid to methyl benzoate and methyl salicylate, respectively. Quantitative real-time polymerase chain reaction analysis showed that LiBSMT was preferentially expressed in petals. Moreover, the expression of LiBSMT in petals was developmentally regulated. These expression patterns correlate well with the emission of methyl benzoate. Our results indicate that LiBSMT plays an important role in floral scent methyl benzoate production and emission in lily flowers.

  9. Investigations and design of pyridine-2-carboxylic acid thiazol-2-ylamide analogs as methionine aminopeptidase inhibitors using 3D-QSAR and molecular docking

    DEFF Research Database (Denmark)

    Hauser, Alexander Sebastian

    2014-01-01

    -dimensional quantitative structure–activity relationship (3D-QSAR) studies were carried out on a series of pyridine-2-carboxylic acid thiazol-2-ylamide-based MetAP inhibitors using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. The models were...... complexes, four new pyridine-2-carboxylic acid thiazol-2-ylamide analogs were designed. These analogs exhibit significantly better predicted activity than the reported molecules. The present work has implications for the development of novel antibiotics as potent MetAP inhibitors....

  10. Swift and efficient sono-hydrolysis of nitriles to carboxylic acids under basic condition: role of the oxide anion radical in the hydrolysis mechanism.

    Science.gov (United States)

    Lignier, Pascal; Estager, Julien; Kardos, Nathalie; Gravouil, Lydie; Gazza, Julien; Naffrechoux, Emmanuel; Draye, Micheline

    2011-01-01

    Carboxylic acids are promising candidates for new sustainable strategies in organic synthesis. In this paper, we ascertain the potential of ultrasound for the hydrolysis of nitriles into carboxylic acids through the study of key parameters of the reaction: pH, hydrolysis medium, reaction time and activation technique. The positive influence of ultrasound under basic conditions is due to more than mechanical effects of cavitation. Indeed, the rate of hydrolysis is dramatically increased under sonication in NaOH solutions. A radical mechanism involving the oxide anion radical O(*-) is proposed. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Binding of carboxylate and trimethylammonium salts to octa-acid and TEMOA deep-cavity cavitands

    Science.gov (United States)

    Sullivan, Matthew R.; Sokkalingam, Punidha; Nguyen, Thong; Donahue, James P.; Gibb, Bruce C.

    2017-01-01

    In participation of the fifth statistical assessment of modeling of proteins and ligands (SAMPL5), the strength of association of six guests ( 3- 8) to two hosts ( 1 and 2) were measured by 1H NMR and ITC. Each host possessed a unique and well-defined binding pocket, whilst the wide array of amphiphilic guests possessed binding moieties that included: a terminal alkyne, nitro-arene, alkyl halide and cyano-arene groups. Solubilizing head groups for the guests included both positively charged trimethylammonium and negatively charged carboxylate functionality. Measured association constants ( K a ) covered five orders of magnitude, ranging from 56 M-1 for guest 6 binding with host 2 up to 7.43 × 106 M-1 for guest 6 binding to host 1.

  12. 1-Alkyl-1,4-dihydro-4-iminoquinoline-3-carboxylic acids

    African Journals Online (AJOL)

    Prof Jo Michael

    The two aforementioned properties of 4-imino acid 2, namely a relatively high solubility in water and a propensity to convert in alkaline medium into the corresponding 4-oxo acid 4 (anion) points to a potential for use in vivo drug delivery5 systems. The mass spectra of the 4-imino acids 2 (R1 = H or Me, Scheme 1) in general.

  13. Prediction of protein modification sites of pyrrolidone carboxylic acid using mRMR feature selection and analysis.

    Directory of Open Access Journals (Sweden)

    Lu-Lu Zheng

    Full Text Available Pyrrolidone carboxylic acid (PCA is formed during a common post-translational modification (PTM of extracellular and multi-pass membrane proteins. In this study, we developed a new predictor to predict the modification sites of PCA based on maximum relevance minimum redundancy (mRMR and incremental feature selection (IFS. We incorporated 727 features that belonged to 7 kinds of protein properties to predict the modification sites, including sequence conservation, residual disorder, amino acid factor, secondary structure and solvent accessibility, gain/loss of amino acid during evolution, propensity of amino acid to be conserved at protein-protein interface and protein surface, and deviation of side chain carbon atom number. Among these 727 features, 244 features were selected by mRMR and IFS as the optimized features for the prediction, with which the prediction model achieved a maximum of MCC of 0.7812. Feature analysis showed that all feature types contributed to the modification process. Further site-specific feature analysis showed that the features derived from PCA's surrounding sites contributed more to the determination of PCA sites than other sites. The detailed feature analysis in this paper might provide important clues for understanding the mechanism of the PCA formation and guide relevant experimental validations.

  14. Synthesis of new derivatives of 1-(3-aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid

    Directory of Open Access Journals (Sweden)

    RAHMI KASIMOGULLAR

    2010-12-01

    Full Text Available 1-(3-Aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid (1 was synthesized according to the literature. 2-(3-Aminophenyl-2,6-dihydro-3,4-diphenyl-7H-pyrazolo[3,4-d]pyridazin-7-one (5 was obtained by the cyclocondensation reaction of 1 with hydrazine hydrate. New pyrazole derivatives of compounds 1 and 5 were synthesized by their reaction with β-diketones, β-ketoesters, β-naphthol, phenol and various other reagents. The structures of the synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR and mass spectroscopy, as well as elemental analysis.

  15. Design, synthesis, and fungicidal activity of novel carboxylic acid amides represented by N-benzhydryl valinamode carbamates.

    Science.gov (United States)

    Du, Xiu-Jiang; Bian, Qiang; Wang, Hong-Xue; Yu, Shu-Jing; Kou, Jun-Jie; Wang, Zhi-Peng; Li, Zheng-Ming; Zhao, Wei-Guang

    2014-08-07

    Carboxylic acid amide (CAA) fungicides are an important class of agricultural fungicide with oomycete activity and low toxicity toward mammalian cells. To find CAA analogues with high activity against resistant pathogens, a series of substituted N-benzhydryl valinamide carbamate derivatives were designed and synthesized by introducing substituted aromatic rings into valinamide carbamate leads. Bioassays showed that some title compounds exhibited very good in vitro fungicidal activity against Phytophthora capsici and in vivo fungicidal activities against Pseudoperonospora cubensis. Topomer CoMFA was performed to explore the structure-activity relationship on the basis of the in vitro data. The dimethoxy substituted aromatic analogue 9e was found to display higher in vitro fungicidal activity against Phytophthora capsici than iprovalicarb but lower activity than mandipropamid, and higher in vivo fungicidal activity against Pseudoperonospora cubensis than dimethomorph at a dosage of 6.25 μg mL(-1).

  16. Non-carboxylic analogues of aryl propionic acid: synthesis, anti-inflammatory, analgesic, antipyretic and ulcerogenic potential.

    Science.gov (United States)

    Eissa, S I; Farrag, A M; Galeel, A A A

    2014-09-01

    As a part of ongoing studies in developing new potent anti-inflammatory and analgesic agents, a series of novel 6-methoxy naphthalene derivatives was efficiently synthesized and characterized by spectral and elemental analyses. The newly synthesized compounds were evaluated for their anti-inflammatory activities using carrageenin-induced rat paw edema model, analgesic activities using acetic acid induced writhing model in mice and anti-pyretic activity using yeast induced hyperpyrexia method as well as ulcerogenic effects. Among the synthesized compounds, thiourea derivative (6a, e) exhibited higher anti-inflammatory activity than the standard drug naproxen in reduction of the rat paw edema (88.71, 89.77%) respectively. All of the non-carboxylic tested compounds were found to have promising anti-inflammatory, analgesic and antipyretic activity, while were devoid of any ulcerogenic effects. © Georg Thieme Verlag KG Stuttgart · New York.

  17. NSAIDs do not require the presence of a carboxylic acid to exert their anti-inflammatory effect - why do we keep using it?

    Science.gov (United States)

    Ullah, Nasir; Huang, Zhangjian; Sanaee, Forough; Rodriguez-Dimitrescu, Alexandra; Aldawsari, Fahad; Jamali, Fakhreddin; Bhardwaj, Atul; Islam, Nazar Ul; Velázquez-Martínez, Carlos A

    2016-12-01

    The carboxylic acid group (-COOH) present in classical NSAIDs is partly responsible for the gastric toxicity associated with the administration of these drugs. This concept has been extensively proven using NSAID prodrugs. However, the screening of NSAIDs with no carboxylic acid at all has been neglected. The goal of this work was to determine if new NSAID derivatives devoid of acidic moieties would retain the anti-inflammatory activity of the parent compound, without causing gastric toxicity. To test this concept, we replaced the carboxylic acid group in ibuprofen, flurbiprofen, and naproxen with three ammonium moieties. We tested the resulting water-soluble NSAID derivatives for anti-inflammatory and ulcerogenic activity in vitro and in vivo. In this regard, we observed that all non-acidic NSAIDs exerted a potent anti-inflammatory activity, suggesting that the acid group in commercial 2-phenylpropionic acid NSAIDs not be an essential requirement for anti-inflammatory activity. These data provide complementary evidence supporting the discontinuation of ulcerogenic acidic NSAIDs.

  18. Synthesis of α-(Pentafluorosulfanyl)- and α-(Trifluoromethyl)-Substituted Carboxylic Acid Derivatives by Ireland-Claisen Rearrangement.

    Science.gov (United States)

    Dreier, Anna-Lena; Beutel, Bernd; Mück-Lichtenfeld, Christian; Matsnev, Andrej V; Thrasher, Joseph S; Haufe, Günter

    2017-02-03

    Earlier studies have shown that [3,3]-sigmatropic rearrangements of allyl esters are useful for the construction of fluorine-containing carboxylic acid derivatives. This paper describes the synthesis of 3-aryl-pent-4-enoic acid derivatives bearing either a pentafluorosulfanyl (SF 5 ) or a trifluoromethyl (CF 3 ) substituent in the 2-position by treatment of corresponding SF 5 - or CF 3 -acetates of p-substituted cinnamyl alcohols with triethylamine followed by trimethylsilyl triflate (TMSOTf). This Ireland-Claisen rearrangement delivered approximate 1:1 mixtures of syn/anti diastereoisomers due to tiny differences (energy of (Z)/(E)-isomeric ester enolates and in the alternative Zimmerman-Traxler transition states of model compounds as shown by DFT calculations. Acidic reaction conditions have to be avoided since addition of the reagents in opposite sequence (first TMSOTf then Et 3 N) led to oligomerization of the cinnamyl SF 5 - and CF 3 -acetates. Treatment of the corresponding regioisomeric 1-phenyl-prop-2-en-1-yl acetates under the latter conditions resulted in [1,3]-sigmatropic rearrangement and subsequent oligomerization of the intermediately formed cinnamyl esters. When Et 3 N was added first followed by TMSOTf, no further reaction of the formed ester was detected.

  19. HTGR fuel development: loading of uranium on carboxylic acid cation-exchange resins using solvent extraction of nitrate

    International Nuclear Information System (INIS)

    Haas, P.A.

    1975-09-01

    The reference fuel kernel for recycle of 233 U to HTGR's (High-Temperature Gas-Cooled Reactors) is prepared by loading carboxylic acid cation-exchange resins with uranium and carbonizing at controlled conditions. The purified 233 UO 2 (NO 3 ) 2 solution from a fuel reprocessing plant contains excess HNO 3 (NO 3 - /U ratio of approximately 2.2). The reference flowsheet for a 233 U recycle fuel facility at Oak Ridge uses solvent extraction of nitrate by a 0.3 M secondary amine in a hydrocarbon diluent to prepare acid-deficient uranyl nitrate. This nitrate extraction, along with resin loading and amine regeneration steps, was demonstrated in 14 runs. No significant operating difficulties were encountered. The process is controlled via in-line pH measurements for the acid-deficient uranyl nitrate solutions. Information was developed on pH values for uranyl nitrate solution vs NO 3 - /U mole ratios, resin loading kinetics, resin drying requirements, and other resin loading process parameters. Calculations made to estimate the capacities of equipment that is geometrically safe with respect to control of nuclear criticality indicate 100 kg/day or more of uranium for single nitrate extraction lines with one continuous resin loading contactor or four batch loading contactors. (auth)

  20. 2-Benzamido-4-methylthiazole-5-carboxylic Acid Derivatives as Potential Xanthine Oxidase Inhibitors and Free Radical Scavengers.

    Science.gov (United States)

    Ali, Md Rahmat; Kumar, Suresh; Afzal, Obaid; Shalmali, Nishtha; Ali, Wazid; Sharma, Manju; Bawa, Sandhya

    2017-02-01

    The new chemical entities febuxostat and topiroxostat have been approved by the US Food and Drug Administration, opening new avenues for exploiting different heterocycles other than purines as xanthine oxidase (XO) inhibitors. A different series of substituted 2-benzamido-4-methylthiazole-5-carboxylic acid derivatives (5a-r) was synthesized and characterized by the collective use of IR, 1 H and 13 C NMR, and mass spectroscopy, for the treatment of gout and hyperuricemia. In vitro studies of the synthesized derivatives revealed that the presence of a fluoro group at the para position in 5b (IC50 = 0.57 μm) and a chloro group in 5c (IC50 = 0.91 μm) signifies excellent XO inhibitory activity among the series, along with their DPPH free radial scavenging activity. In vivo serum uric acid inhibition studies established that 5b and 5c displayed 62 and 53% uric acid inhibition, respectively. Studies on enzyme kinetics indicated that 5b acts as a mixed type inhibitor. In silico prediction by various softwares also helped in the recognition of potent XO inhibitors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Mass spectrometric studies of stable isotope-labelled carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Andersson, B.Aa.; Dinger, F.; Dinh-Nguyen, N.

    1975-01-01

    Low resolution mass spectra of deuterium and carbon-13 labelled fatty acid pyrrolidides are discussed. The simple fragmentation pattern of pyrrolidides makes them superior to other derivatives, regarding location of isotopes. Deuteriation of ethylenic fatty acid pyrrolidides therefore seems to be an improved method to locate carbon-carbon double bonds by mass spectrometry. (author)

  2. CEC enantioseparations of carboxylic acids on silica-based monoliths modified with ergot alkaloid derivative

    Czech Academy of Sciences Publication Activity Database

    Messina, A.; Moroni, S.; Flieger, Miroslav; Sinibaldi, M.; Ursini, O.

    2009-01-01

    Roč. 30, č. 16 (2009), s. 2890-2896 ISSN 0173-0835 Institutional research plan: CEZ:AV0Z50200510 Keywords : 2-Aryloxypropionic acids * chiral separations * dansyl amino acid derivatives Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.077, year: 2009

  3. One pot direct synthesis of amides or oxazolines from carboxylic acids using Deoxo-Fluor reagent.

    Science.gov (United States)

    Kangani, Cyrous O; Kelley, David E

    2005-12-19

    A mild and highly efficient one pot-one step condensation and/or condensation-cyclization of various acids to amides and/or oxazolines using Deoxo-Fluor reagents is described. Parallel syntheses of various free fatty acids with 2-amino-2, 2-dimethyl-1-propanol resulted with excellent yields.

  4. Separation of carboxylic acids in human serum by isotachophoresis using a commercial field-deployable analytical platform combined with in-house glass microfluidic chips

    Czech Academy of Sciences Publication Activity Database

    Smejkal, P.; Breadmore, M. C.; Guijt, R. M.; Grym, Jakub; Foret, František; Bek, F.; Macka, M.

    2012-01-01

    Roč. 755, NOV 28 (2012), s. 115-120 ISSN 0003-2670 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : ITP system * carboxylic acids * microfluidic chips Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.387, year: 2012

  5. Mechanism of Alkene, Alkane, and Alcohol Oxidation with H2O2 by an in Situ Prepared Mn-II/Pyridine-2-carboxylic Acid Catalyst

    NARCIS (Netherlands)

    Saisaha, Pattama; Dong, Jia Jia; Meinds, Tim G.; de Boer, Johannes W.; Hage, Ronald; Mecozzi, Francesco; Kasper, Johann B.; Browne, Wesley R.

    The oxidation of alkenes, alkanes, and alcohols with H2O2 is catalyzed efficiently using an in situ prepared catalyst comprised of a MnII salt and pyridine-2-carboxylic acid (PCA) together with a ketone in a wide range of solvents. The mechanism by which these reactions proceed is elucidated, with a

  6. Tropanol esters of metallocene carboxylic acids. Syntheses, labelling with /sup 103/Ru and sup(103m)Rh and organ distribution

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, M.; Wu, Y.

    1988-01-01

    The tropanol esters of the carboxylic acids of ferrocene, /sup 103/Ru-ruthenocene and sup(103m)Rh-rhodocinium were synthezised. The organ distribution of the /sup 103/Ru or sup(103m)Rh labelled tropanol-esters were investigated. Only the /sup 103/Ru labelled ester showed a high heartblood ratio.

  7. Hydrophilic carboxylic acids and iridoid glycosides in the juice of American and European cranberries (Vaccinium macrocarpon and V. oxycoccos), lingonberries (V. vitis-idaea), and blueberries (V. myrtillus)

    DEFF Research Database (Denmark)

    Jensen, Heidi Dorthe; Krogfelt, Karen A; Cornett, Claus

    2002-01-01

    iridoid glucosides were shown to be monotropein and 6,7-dihydromonotropein by MS and NMR spectroscopy. A fast reversed-phase HPLC method for quantification of the hydrophilic carboxylic acids was developed and used for analyses of cranberry, lingonberry, and blueberry juices. The level of hydrophilic...

  8. Orientation of Pterin-6-Carboxylic Acid on Gold Capped Silicon Nanopillars Platforms: Surface Enhanced Raman Spectroscopy and Density Functional Theory Studies

    DEFF Research Database (Denmark)

    Castillo, John J.; Rozo, Ciro E.; Bertel, Linda

    2016-01-01

    The orientation of pterin-6-carboxylic acid on gold nanopillars was investigated by surface enhanced Raman spectroscopy and density functional theory methods. The experimentally vibrations from pterin-6-COOH free and attached to the Au surface display vibration features indicating chemical...

  9. Trametes versicolor carboxylate reductase uncovered.

    Science.gov (United States)

    Winkler, Margit; Winkler, Christoph K

    The first carboxylate reductase from Trametes versicolor was identified, cloned, and expressed in Escherichia coli . The enzyme reduces aromatic acids such as benzoic acid and derivatives, cinnamic acid, and 3-phenylpropanoic acid, but also aliphatic acids such as octanoic acid are reduced.

  10. A general three-step one-pot synthesis of novel (E)-6-chloro-2-(aryl/hetarylvinyl)quinoline-3-carboxylic acids.

    Science.gov (United States)

    Li, Yang; Wang, Yang; Zou, Hongtao

    2017-05-01

    In this work, a facile and general three-step one-pot synthesis of structurally new (E)-6-chloro-2-(aryl/hetarylvinyl)quinoline-3-carboxylic acid derivatives has been achieved from easily available ethyl 6-chloro-2-(chloromethyl) quinoline-3-carboxylate and aromatic or heteroaromatic aldehydes. This strategy features simple one-pot operation, tolerance of a wide range of substituents, and good yields. Moreover, these newly synthesized compounds belong to a new class of quinoline derivatives and could be good candidates for the development of more complex quinoline compounds for use in medicinal chemistry.

  11. New co-crystal and salt form of sulfathiazole with carboxylic acid and ...

    Indian Academy of Sciences (India)

    aminobenzamide and 2,4- dinitrobenzoic acid have been synthesized. These new forms are characterized by single crystal X-ray diffrac- tion, infrared spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

  12. Complexes of molybdenum (6) and tungsten (6) with amino- and pyridine carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V.I.; Mozgin, S.V.; Felin, M.G.; Subbotina, N.A.; Ajzenberg, M.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

    1984-01-01

    By interaction of Na/sub 2/MO/sub 4/ with amino acid excess in muriatic medium the complexes Mo/sub 2/O/sub 4/ (OH)/sub 3/L (LH-anthranilic, nicotinic acids, histidine), Mo/sub 2/O/sub 5/ (OH)L' (L'H-..cap alpha..- and ..beta..-alanine, valine, isonicotinic acid), W/sub 3/O/sub 8/ (OH) (H/sub 2/O)/sub 4/ L'' (L'H-nicotinic, isonicotinic acids, histidine) are isolated. On the basis of the data of elementary analysis, IR spectroscopy and thermogravimetry assumptions on their composition and structure have been suggested.

  13. Direct Hydrogenation of Biobased Carboxylic Acids Mediated by a Nitrogen-centered Tridentate Phosphine Ligand.

    Science.gov (United States)

    Deng, Li; Kang, Bin; Englert, Ulli; Klankermayer, Jürgen; Palkovits, Regina

    2016-01-01

    A novel nitrogen-centered tridentate ligand was identified from a series of multidentate ligands and applied for the direct hydrogenation of 9 biogenic acids into alcohols, lactones and esters with high yields. Comparison of substrates and ruthenium precursors suggested that the Ru(II) hydride cationic species was more active to transform acids than the corresponding lactone or esters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Effect of phenols and carboxylic acids on photochromism of 1-alkyl-2-(arylazo)imidazoles

    International Nuclear Information System (INIS)

    Gayen, Pallab; Sinha, Chittaranjan

    2012-01-01

    Light irradiated trans-to-cis isomerization of 1-alkyl-2-(arylazo)imidazole in the presence of phenol, catechol, benzoic acid and salicylic acid (called co-factors) has been studied in this work. The rate of trans→cis photoisomerization is decreased in the presence of co-factor in the medium and is dependent on the concentration of active quotient about photochrome. The decrease in rate follows catechol>benzoic acid>phenol>salicylic acid. This trend is due to the effects of dissociation ability of –O–H/–COOH, intermolecular association of the molecules etc. The reverse change, cis-to-trans, is very slow in light irradiation and has been carried out by a thermal process in the dark. The quantum yield of isomerization follows the same sequence of effects of co-factors. - Highlights: ► Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. ► The process is sensitive to the environment of the photochrome and the solution. ► The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. ► The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. ► The activation energy is less than these values when carried out in fresh solution only.

  15. Mixed culture syngas fermentation and conversion of carboxylic acids into alcohols.

    Science.gov (United States)

    Liu, Kan; Atiyeh, Hasan K; Stevenson, Bradley S; Tanner, Ralph S; Wilkins, Mark R; Huhnke, Raymond L

    2014-01-01

    Higher alcohols such as n-butanol and n-hexanol have higher energy density than ethanol, are more compatible with current fuel infrastructure, and can be upgraded to jet and diesel fuels. Several organisms are known to convert syngas to ethanol, but very few can produce higher alcohols alone. As a potential solution, mixed culture fermentation between the syngas fermenting Alkalibaculum bacchi strain CP15 and propionic acid producer Clostridium propionicum was studied. The monoculture of CP15 produced only ethanol from syngas without initial addition of organic acids to the fermentation medium. However, the mixed culture produced ethanol, n-propanol and n-butanol from syngas. The addition of propionic acid, butyric acid and hexanoic acid to the mixed culture resulted in a 50% higher conversion efficiency of these acids to their respective alcohols compared to CP15 monoculture. These findings illustrate the great potential of mixed culture syngas fermentation in production of higher alcohols. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. In-situ spectroscopic investigations of the redox behavior of poly(indole-5-carboxylic-acid) modified electrodes in acidic aqueous solutions.

    Science.gov (United States)

    Talbi, H; Billaud, D; Louarn, G; Pron, A

    2001-03-01

    The oxidation of electrochemically grown poly(indole-5-carboxylic-acid) (P5CO2H) and its spectroscopic properties have been studied by in-situ spectroelectrochemical techniques. The purpose of this paper is to characterize the different modifications on the P5CO2H backbone, induced by the electrochemical oxidation in aqueous acidic solution. We have identified, on the basis of Raman spectra, the vibrational modes associated with neutral and oxidized segments of polymer. It was shown that at least three chemically and optically different species (perhaps other products too) are produced in different potential regimes upon oxidation of this polymer. The results obtained also indicate that the molecular properties of this conducting polymer are better revealed by in-situ resonant spectra than by ex-situ infrared and Raman studies.

  17. Proton-conducting membranes based on benzimidazole-containing sulfonated poly(ether ether ketone) compared with their carboxyl acid form

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongtao; Wu, Jing; Zhao, Chengji; Zhang, Gang; Zhang, Yang; Shao, Ke; Xu, Dan; Lin, Haidan; Han, Miaomiao; Na, Hui [Alan G MacDiarmid Institute, College of Chemistry, Jilin University, Changchun 130012 (China)

    2009-10-15

    A series of sulfonated poly(ether ether ketone) containing pendant carboxyl (C-SPEEKs) have been synthesized using a nucleophilic polycondesation reaction. A condensation reaction between 1,2-diaminobenzene and carboxyl resulted in a new series of copolymers containing benzimidazole groups (SPEEK-BIms). The expected structures of the sulfonated copolymers are confirmed by {sup 1}H NMR. The dependence of ion exchange capacity, water uptake, proton conductivity and methanol diffusion coefficient of SPEEK-BIm membranes has been studied and compared with their carboxyl acid form. The results suggest that the introduction of benzimidazole groups may be responsible for many excellent properties of the membranes for fuel cell. It is noticeable that the markedly improved oxidative stability is benefit for the application of membrane. (author)

  18. Calculated Third Order Rate Constants for Interpreting the Mechanisms of Hydrolyses of Chloroformates, Carboxylic Acid Halides, Sulfonyl Chlorides and Phosphorochloridates

    Directory of Open Access Journals (Sweden)

    T. William Bentley

    2015-05-01

    Full Text Available Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1 to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3 are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides. Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride.

  19. Spectroscopic and first principles investigation on 4-[(4-pyridinylmethylene)amino]-benzoic acid bearing pyridyl and carboxyl anchoring groups

    Science.gov (United States)

    Zhang, Lei; Wang, Qiaoyi

    2018-03-01

    We report a combined experimental and computational investigation on the structure and photophysics of 4-[(4-pyridinylmethylene)amino]-benzoic acid, a functional molecule bearing two anchoring groups for attachment onto a TiO2 surface and perovskite surface, for potential solar cell application. This molecule possesses interesting adsorption properties in perovskite solar cell because the pyridyl group serves as the Lewis base and targets Lewis acidic sites in the perovskite surface, while the carboxyl group targets TiO2 surface, improving the coupling between the perovskite surface and the TiO2 surface. The electronic structures of the molecule and its photochemistry are revealed by the UV-vis absorption spectra and the fluorescence spectra under visible light irradiation, which are combined with density functional theory (DFT) and time-dependent density functional theory (TDDFT) analysis. Considering the bi-anchoring groups and the conjugated π system embedded in the molecule, we anticipate it can molecular engineer the TiO2/perovskite interface in perovskite solar cell.

  20. Single amino acids in the carboxyl terminal domain of aquaporin-1 contribute to cGMP-dependent ion channel activation

    Directory of Open Access Journals (Sweden)

    Yool Andrea J

    2003-10-01

    Full Text Available Abstract Background Aquaporin-1 (AQP1 functions as an osmotic water channel and a gated cation channel. Activation of the AQP1 ion conductance by intracellular cGMP was hypothesized to involve the carboxyl (C- terminus, based on amino acid sequence alignments with cyclic-nucleotide-gated channels and cGMP-selective phosphodiesterases. Results Voltage clamp analyses of human AQP1 channels expressed in Xenopus oocytes demonstrated that the nitric oxide donor, sodium nitroprusside (SNP; 3–14 mM activated the ionic conductance response in a dose-dependent manner. Block of soluble guanylate cyclase prevented the response. Enzyme immunoassays confirmed a linear dose-dependent relationship between SNP and the resulting intracellular cGMP levels (up to 1700 fmol cGMP /oocyte at 14 mM SNP. Results here are the first to show that the efficacy of ion channel activation is decreased by mutations of AQP1 at conserved residues in the C-terminal domain (aspartate D237 and lysine K243. Conclusions These data support the idea that the limited amino acid sequence similarities found between three diverse classes of cGMP-binding proteins are significant to the function of AQP1 as a cGMP-gated ion channel, and provide direct evidence for the involvement of the AQP1 C-terminal domain in cGMP-mediated ion channel activation.

  1. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Ruth; Bhaumik, Asim [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Dutta, Saikat [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-11-01

    A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state {sup 13}C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N{sub 2} sorption, HR-TEM, and NH{sub 3} temperature programmed desorption-thermal conductivity detector (TPD-TCD) analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H)-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  2. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Directory of Open Access Journals (Sweden)

    Ruth Gomes

    2014-11-01

    Full Text Available A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state 13C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N2 sorption, HR-TEM, and NH3 temperature programmed desorption-thermal conductivity detector (TPD-TCD analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  3. Synthesis of purin-2-yl carboxylate from O6-methylguanosine.

    Science.gov (United States)

    Maruyama, Tokumi; Moriwaka, Nobuyasu; Demizu, Yosuke; Ohtsuka, Masami

    2005-01-01

    O6-methylguanosine derivative was treated with sodium nitrite or isoamylnitrite in the presence of the carboxylic acid to give the purin-2-yl carboxylate (2), an unusual product bearing a carboxylic group at 2-position of purine moiety.

  4. Adsorption of Carboxylic Acids on Reservoir Minerals from Organic and Aqueous Phase

    DEFF Research Database (Denmark)

    Madsen, Lene; Lind, Ida

    1998-01-01

    Adsorption of organic acids onto North Sea chalk and pure minerals from a hydrocarbon phase and an aqueous phase show that the maximum adsorption is larger for calcite than for silicate surfaces in the hydrocarbon phase. The opposite is observed, however, in the aqueous phase. This suggests...

  5. Case Studies in Systems Chemistry. Final Report. [Includes Complete Case Study, Carboxylic Acid Equilibria

    Science.gov (United States)

    Fleck, George

    This publication was produced as a teaching tool for college chemistry. The book is a text for a computer-based unit on the chemistry of acid-base titrations, and is designed for use with FORTRAN or BASIC computer systems, and with a programmable electronic calculator, in a variety of educational settings. The text attempts to present computer…

  6. Atmospheric chemistry of perfluorinated carboxylic acids: Reaction with OH radicals and atmospheric lifetimes

    DEFF Research Database (Denmark)

    Hurley, MD; Andersen, Mads Peter Sulbæk; Wallington, TJ

    2004-01-01

    Relative rate techniques were used to study the kinetics of the reactions of OH radicals with a homologous series of perfluorinated acids, F(CF2)(n)COOH (n = 1, 2, 3, 4), in 700 Torr of air at 296 +/- 2 K. For n > 1, the length of the F(CF2)(n) group had no discernible impact on the reactivity of...

  7. Engineering Escherichia coli for the synthesis of short- and medium-chain α,β-unsaturated carboxylic acids.

    Science.gov (United States)

    Kim, Seohyoung; Cheong, Seokjung; Gonzalez, Ramon

    2016-07-01

    Concerns over sustained availability of fossil resources along with environmental impact of their use have stimulated the development of alternative methods for fuel and chemical production from renewable resources. In this work, we present a new approach to produce α,β-unsaturated carboxylic acids (α,β-UCAs) using an engineered reversal of the β-oxidation (r-BOX) cycle. To increase the availability of both acyl-CoAs and enoyl-CoAs for α,β-UCA production, we use an engineered Escherichia coli strain devoid of mixed-acid fermentation pathways and known thioesterases. Core genes for r-BOX such as thiolase, hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and enoyl-CoA reductase were chromosomally overexpressed under the control of a cumate inducible phage promoter. Native E. coli thioesterase YdiI was used as the cycle-terminating enzyme, as it was found to have not only the ability to convert trans-enoyl-CoAs to the corresponding α,β-UCAs, but also a very low catalytic efficiency on acetyl-CoA, the primer and extender unit for the r-BOX pathway. Coupling of r-BOX with YdiI led to crotonic acid production at titers reaching 1.5g/L in flask cultures and 3.2g/L in a controlled bioreactor. The engineered r-BOX pathway was also used to achieve for the first time the production of 2-hexenoic acid, 2-octenoic acid, and 2-decenoic acid at a final titer of 0.2g/L. The superior nature of the engineered pathway was further validated through the use of in silico metabolic flux analysis, which showed the ability of r-BOX to support growth-coupled production of α,β-UCAs with a higher ATP efficiency than the widely used fatty acid biosynthesis pathway. Taken together, our findings suggest that r-BOX could be an ideal platform to implement the biological production of α,β-UCAs. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  8. Quantum Chemical Calculation of p Kas of Environmentally Relevant Functional Groups: Carboxylic Acids, Amines and Thiols in Aqueous Solution.

    Science.gov (United States)

    Lian, Peng; Johnston, Ryne C; Parks, Jerry M; Smith, Jeremy C

    2018-04-10

    Developing accurate quantum chemical approaches for calculating p K a s is of broad interest. Useful accuracy can be obtained by using density functional theory (DFT) in combination with a polarizable continuum solvent model. However, some classes of molecules present problems for this approach, yielding errors greater than 5 p K units. Various methods have been developed to improve the accuracy of the combined strategy. These methods perform well, but either do not generalize or introduce additional degrees of freedom, increasing the computational cost. The Solvation Model based on Density (SMD) has emerged as one of the most commonly used continuum solvent models. Nevertheless, for some classes of organic compounds, e.g. thiols, the p K a s calculated with the original SMD model show errors of 6-10 p K units, and we traced these errors to inaccuracies in the solvation free energies of the anions. To improve the accuracy of p K a s calculated with DFT and the SMD model, we developed a scaled solvent-accessible surface approach for constructing the solute-solvent boundary. By using a 'direct' approach in which all quantities are computed in the presence of the continuum solvent, the use of thermodynamic cycles is avoided. Furthermore, no explicit water molecules are required. Three benchmark datasets of experimentally measured p K a values, including 28 carboxylic acids, 10 aliphatic amines, and 45 thiols, were used to assess the optimized SMD model, which we call SMD with a scaled solvent-accessible surface (SMD sSAS ). Of the methods tested, the M06-2X density functional approximation, 6-31+G(d,p) basis set, and SMD sSAS solvent model provided the most accurate p K a s for each set, yielding mean unsigned errors of 0.9, 0.4, and 0.5 p K units, respectively, for carboxylic acids, aliphatic amines, and thiols. This approach is therefore useful for efficiently calculating the p K a s of environmentally relevant functional groups.

  9. Two multi-dimensional frameworks constructed from zinc coordination polymers with pyridine carboxylic acids

    International Nuclear Information System (INIS)

    Guo Yuanyuan; Ma Pengtao; Wang Jingping; Niu Jingyang

    2011-01-01

    Two novel zinc coordination polymers [Zn 2 (H 2 O)L(MoO 4 )] n (1) and [Zn 4 (PO 4 ) 2 L'(H 2 O)] n (2) (H 2 L=2,2'-bipyridine-6.6'-dicarboxylic acid, H 2 L'=2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, UV spectra, single-crystal X-ray diffraction and thermogravimetric analyses. Structural analyses indicate that 1 represents a 2-D sheet structure built by dimeric [Zn 2 L(H 2 O)] 2+ units and MoO 4 2- groups whereas 2 displays an interesting 3-D framework constructed by tetranuclear zinc clusters, L' 2- ligands and PO 4 3- groups. Examination of UV spectra suggests that both 1 and 2 can stably exist in the pH range of 2.45-5.45 and 3.01-8.55 in aqueous solution, respectively. The room-temperature solid-state photoluminescence of 1 and 2 are derived from the intra-ligands π-π* transitions of H 2 L and H 2 L' ligands and the ligand-to-metal-charge-transfer transitions. - Graphical Abstract: Two new transition metal coordination polymers, namely, [Zn 2 (H 2 O)L 1 (MoO 4 )] n (1), [Zn 4 (PO 4 ) 2 L 2 (H 2 O)] n (2) (H 2 L 1 =2,2'-bipyridine-6,6'-dicarboxylic acid, H 2 L 2 =2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized. 1 represents a 2-D sheet structure while 2 represents 3-D network. Highlights: →Two new transition metal coordination polymers have been hydrothermally synthesized. → The two compounds have been characterized by elemental analyses, IR, UV spectra, single-crystal X-ray diffraction, thermogravimetric analyses and photoluminescence. → Compound 1 represents a 2-D sheet structure while 2 represents 3-D network.

  10. Actions of a proline analogue, L-thiazolidine-4-carboxylic acid (T4C, on Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Anahí Magdaleno

    Full Text Available It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C. The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC(50 = 0.89+/-0.02 mM at 28 degrees C, and the inhibitory effect of this analogue was synergistic (p<0.05 with temperature (0.54+/-0.01 mM at 37 degrees C. T4C significantly diminished parasite survival (p<0.05 in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM. All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress.

  11. Fe(6-Me-PyTACN)-catalyzed, one-pot oxidative cleavage of methyl oleate and oleic acid into carboxylic acids with H2O2 and NaIO4

    NARCIS (Netherlands)

    Spannring, Peter; Prat, Irene; Costas, Miquel; Lutz, Martin; Bruijnincx, Pieter C. A.; Weckhuysen, Bert. M.; Klein Gebbink, Bert

    2014-01-01

    The first Fe-based catalytic system for the oxidative cleavage of unsaturated fatty acids and esters to carboxylic acids is reported. The system comprises [Fe(OTf)(2)(6-Me-PyTACN)] (2) (6-Me-PyTACN = 1-[(6-methyl-2-pyridyl) methyl]-4,7-dimethyl-1,4,7-triazacyclononane, OTf = trifluoromethane

  12. Field Observation of Heterogeneous Formation of Dicarboxylic acids, Keto-carboxylic acids, α-Dicarbonyls and Nitrate in Xi'an, China during Asian dust storm periods

    Science.gov (United States)

    Wang, G.; Wang, J.; Ren, Y.; Li, J.

    2015-12-01

    To understand the formation mechanism of secondary organic aerosols (SOA) on dust surfaces, this study investigated the concentrations and compositions of dicarboxylic acids (C2-C11), keto-carboxylic acids (C3-C7), α-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) collected in Xi'an, China during the nondust storm and dust storm periods of 2009 and 2011. During the events the ambient particulate dicarboxylic acids were 932-2240 ng m-3, which are comparable and even higher than those in nondust periods. Molecular compositions of the above SOA are similar to those in nondust periods with oxalic acid being the leading species. In the presence of the dust storms, all the above mentioned SOA species in Xi'an were predominantly enriched on the coarse particles (>2.1μm), and oxalic acid well correlated with NO3- (R2=0.72, pfine particles and a strong correlation of oxalic acid with SO42-. Our results further demonstrate that NO3- in the dust periods in Xi'an was mostly derived from secondary oxidation, whereas SO42- during the events was largely derived from surface soil of Gobi deserts. We propose a formation pathway to explain these observations, in which nitric acid and/or nitrogen oxides react with dust to produce Ca(NO3)2 and form a liquid phase on the surface of dust aerosols via water vapor-absorption of Ca(NO3)2, followed by a partitioning of the gas-phase water-soluble organic precursors (e.g.,glyoxal and methylglyoxal) into the aqueous-phase and a subsequent oxidation into oxalic acid. To the best of our knowledge, we found for the first time the enrichment of glyoxal and methylglyoxal on dust surface. Our data suggest an important role of nitrate in the heterogeneous formation process of SOA on the surface of Asian dust.

  13. In situ SERS and X-ray photoelectron spectroscopy studies on the pH-dependant adsorption of anthraquinone-2-carboxylic acid on silver electrode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dan, E-mail: dany@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Jia, Shaojie [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Fodjo, Essy Kouadio [Laboratory of Physical Chemistry, University Felix Houphouet Boigny, 22 BP 582, Abidjan 22, Cote d’Ivoire (Cote d' Ivoire); Xu, Hu [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Wang, Yuhong, E-mail: yuhong_wang502@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Deng, Wei [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

    2016-03-30

    Graphical abstract: The orientation of anthraquinone-2-carboxylic acid (AQ-2-COOH) has been investigated by in situ surface-enhanced Raman scattering (in situ SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) on silver surface. - Highlights: • The adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on Ag electrode is influenced by the pH. • The pH-dependant adsorption of AQ-2-COOH has been confirmed by in situ surface-enhanced Raman scattering (in situ SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS). • The results can provide insights into electron transfer reactions of AQ-2-COOH in biological systems. - Abstract: In this study, in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) are used to investigate the redox reaction and adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on an Ag electrode at different pH values. The obtained results indicate that AQ-2-COOH is adsorbed tilted on the Ag electrode through O-atom of ring carbonyl in a potential range from −0.3 to −0.5 V vs. SCE, but the orientation turns to more tilted orientation with both O-atom of the ring carbonyl and carboxylate group in positive potential region for pH 6.0 and 7.4. However, at pH 10.0, the orientation adopts tilted conformation constantly on the Ag electrode with both O-atom of the anthraquinone ring and carboxylate group in the potential range from −0.3 to −0.5 V vs. SCE or at positive potentials. Moreover, the adsorption behavior of AQ-2-COOH has been further confirmed by AR-XPS on the Ag surface. Proposed reasons for the observed changes in orientation are presented.

  14. Functionalization and Chemical Modification of 2-Hydroxyethyl Methacrylate with Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Nasirtabrizi

    2012-01-01

    Full Text Available Free radical polymerization of the resulting monomers methyl methacrylate (MMA, ethyl methacrylate (EMA, methylacrylate (MA and ethylacrylate (EA with 2-hydroxyethyl methacrylate (HEMA (in 1:1 mole ratio were carried out using azobis(isoboutyronitrile (AIBN as initiator at the temperature ranges 60-70°C. The modification of polymers were carried out by 9-anthracenecarboxylic acid (9-ACA via the esterification reaction between —OH of poly(HEMA and —COOH of 9-ACA, in presence of N,N′-dicyclohexyl-carbodiimide (DCC, 4-(dimethylamino pyridine (DMAP and N,N-dimethyl formamid (DMF. It was found that the molar ratio acid/alcohol/catalysts= 0.02: 0.02: 0.02 and 0.002, optimal for preparation of the ester. As demonstrated by FT-IR, 1H-NMR and dynamic mechanical thermal analysis (DMTA. The Tg value of methacrylate and acrylate copolymers containing 9-ACA groups was found to increase with incorporation of 9-ACA groups in polymer structures. The presence of 9-ACA groups in the polymer side chains created new polymers with novel modified properties that find some applications in polymer industry. These anthracenic factors could take part in cyclo addition reaction with other factors such as anhydrides and kinons.

  15. Hydrazones of 2-aryl-quinoline-4-carboxylic acid hydrazides: synthesis and preliminary evaluation as antimicrobial agents.

    Science.gov (United States)

    Metwally, Kamel A; Abdel-Aziz, Lobna M; Lashine, El-Sayed M; Husseiny, Mohamed I; Badawy, Rania H

    2006-12-15

    A new series of 2-arylquinoline-4-carboxylic acid hydrazide-hydrazones was synthesized using an appropriate synthetic route. All the target compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus as an example for Gram-positive bacteria, Escherichia coli as an example for Gram-negative bacteria, and Candida albicans as a representative of fungi. The minimum inhibitory concentration (MIC) was determined for test compounds as well as for reference standards. Among the compounds tested, compounds having nitro substituents at the arylidene moiety showed the most potent antifungal as well as antibacterial activities against E. coli. Compound 23 displayed an antifungal activity comparable to that of nystatin. However, none of the compounds demonstrated any antibacterial activity against S. aureus. Hydrophobicity of the target compounds correlated weakly with their antibacterial and antifungal activities. The most potent compounds namely, 7, 18, 19, 22, and 23 were assessed for hemolytic toxicity and found to be non-hemolytic up to a concentration of 100mug/mL. In addition, the most potent compound (23) was evaluated for in vitro cytotoxic activity against various cancer cell lines. This compound was found to display no cytotoxic activity but rather it induces the proliferation rate of Hep-G2 cells.

  16. Meso-ester and carboxylic acid substituted BODIPYs with far-red and near-infrared emission for bioimaging applications

    KAUST Repository

    Ni, Yong

    2014-01-21

    A series of meso-ester-substituted BODIPY derivatives 1-6 are synthesized and characterized. In particular, dyes functionalized with oligo(ethylene glycol) ether styryl or naphthalene vinylene groups at the α positions of the BODIPY core (3-6) become partially soluble in water, and their absorptions and emissions are located in the far-red or near-infrared region. Three synthetic approaches are attempted to access the meso-carboxylic acid (COOH)-substituted BODIPYs 7 and 8 from the meso-ester-substituted BODIPYs. Two feasible synthetic routes are developed successfully, including one short route with only three steps. The meso-COOH-substituted BODIPY 7 is completely soluble in pure water, and its fluorescence maximum reaches around 650 nm with a fluorescence quantum yield of up to 15 %. Time-dependent density functional theory calculations are conducted to understand the structure-optical properties relationship, and it is revealed that the Stokes shift is dependent mainly on the geometric change from the ground state to the first excited singlet state. Furthermore, cell staining tests demonstrate that the meso-ester-substituted BODIPYs (1 and 3-6) and one of the meso-COOH-substituted BODIPYs (8) are very membrane-permeable. These features make these meso-ester- and meso-COOH-substituted BODIPY dyes attractive for bioimaging and biolabeling applications in living cells. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Cytotoxicity of Benzaldehyde Nitrogen Mustard-2-Pyridine Carboxylic Acid Hydrazone Being Involved in Topoisomerase IIα Inhibition

    Directory of Open Access Journals (Sweden)

    Yun Fu

    2014-01-01

    Full Text Available The antitumor property of iron chelators and aromatic nitrogen mustard derivatives has been well documented. Combination of the two pharmacophores in one molecule in drug designation is worth to be explored. We reported previously the syntheses and preliminary cytotoxicity evaluation of benzaldehyde nitrogen mustard pyridine carboxyl acid hydrazones (BNMPH as extended study, more tumor cell lines (IC50 for HepG2: 26.1 ± 3.5 μM , HCT-116: 57.5 ± 5.3 μM, K562: 48.2 ± 4.0 μM, and PC-12: 19.4 ± 2.2 μM were used to investigate its cytotoxicity and potential mechanism. In vitro experimental data showed that the BNMPH chelating Fe2+ caused a large number of ROS formations which led to DNA cleavage, and this was further supported by comet assay, implying that ROS might be involved in the cytotoxicity of BNMPH. The ROS induced changes of apoptosis related genes, but the TFR1 and NDRG1 metastatic genes were not obviously regulated, prompting that BNMPH might not be able to deprive Fe2+ of ribonucleotide reductase. The BNMPH induced S phase arrest was different from that of iron chelators (G1 and alkylating agents (G2. BNMPH also exhibited its inhibition of human topoisomerase IIα. Those revealed that the cytotoxic mechanism of the BNMPH could stem from both the topoisomerase II inhibition, ROS generation and DNA alkylation.

  18. Crystal structure and ligand affinity of avidin in the complex with 4‧-hydroxyazobenzene-2-carboxylic acid

    Science.gov (United States)

    Strzelczyk, Paweł; Bujacz, Grzegorz

    2016-04-01

    Avidin is a protein found in egg white that binds numerous organic compounds with high affinity, especially biotin and its derivatives. Due to its extraordinary affinity for its ligands, avidin is extensively used in biotechnology. X-ray crystallography and fluorescence-based biophysical techniques were used to show that avidin binds the dye 4‧-hydroxyazobenzene-2-carboxylic acid (HABA) with a lower affinity than biotin. The apparent dissociation constant determined for the avidin complex with HABA by microscale thermophoresis (MST) is 4.12 μM. The crystal structure of avidin-HABA complex was determined at a resolution of 2.2 Å (PDB entry 5chk). The crystals belong to a hexagonal system, in the space group P6422. In that structure, the hydrazone tautomer of HABA is bound at the bottom part of the central calyx near the polar residues. We show interactions of the dye with avidin and compare them with the previously reported avidin-biotin complex.

  19. Solvent extraction of uranium(VI) and thorium(IV) from nitrate media by carboxylic acid amides

    International Nuclear Information System (INIS)

    Preston, J.S.; Preez, A.C. du

    1995-01-01

    A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR 2 ') and non-substituted amides (R.CO.NH 2 ) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities. The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35 degree C. In contrast, the N,N-dialkyl amides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides. 15 refs., 8 figs., 8 tabs

  20. Complete Genome Sequence of Pseudomonas Parafulva PRS09-11288, a Biocontrol Strain Produces the Antibiotic Phenazine-1-carboxylic Acid.

    Science.gov (United States)

    Zhang, Yu; Chen, Ping; Ye, Guoyou; Lin, Haiyan; Ren, Deyong; Guo, Longbiao; Zhu, Bo; Wang, Zhongwei

    2018-01-22

    Rhizoctonia solani is a plant pathogenic fungus, which can infect a wide range of economic crops including rice. In this case, biological control of this pathogen is one of the fundmental way to effectively control this pathogen. The Pseudomonas parafulva strain PRS09-11288 was isolated from rice rhizosphere and shows biocontrol ability against R. solani. Here, we analyzed the P. parafulva genome, which is ~ 4.7 Mb, with 4310 coding sequences, 76 tRNAs, and 7 rRNAs. Genome analysis identified a phenazine biosynthetic pathway, which can produce antibiotic phenazine-1-carboxylic acid (PCA). This compound is responsible for biocontrol ability against R. solani Kühn, which is one of the most serious fungus disease on rice. Analysis of the phenazine biosynthesis gene mutant, ΔphzF, which is very important in this pathway, confirmed the relationship between the pathway and PCA production using LC-MS profiles. The annotated full genome sequence of this strain sheds light on the role of P. parafulva PRS09-11288 as a biocontrol bacterium.

  1. Assessment of exposure to carbon disulfide in viscose production workers from urinary 2-thiothiazolidine-4-carboxylic acid determinations

    Energy Technology Data Exchange (ETDEWEB)

    Riihimaeki, V.K.; Kivistoe, H.P.; Peltonen, K.; Helpioe, E.A.; Aitio, A. (Department of Industrial Hygiene and Toxicology, Institute of Occupational Health, Helsinki (Finland))

    1992-01-01

    The follow-up of environmental carbon disulfide (CS2) exposure and urinary excretion of 2-thiothiazolidine-4-carboxylic acid (TTCA) among 20 operatives over a 4-day working week in two viscose producing factories confirmed earlier observations that TTCA is a sensitive and reliable indicator of exposure to CS2. Exposure to as low as 0.5-1.0 ppm (1.6-3.2 mg/m3) of CS2 (8-hour time-weighted average [TWA]) was associated with detectable amounts of TTCA in end-of-shift urine. Moreover, the excretion of TTCA, relative to estimated CS2 uptake, appeared surprisingly constant in the studied work force. Approximately 3% (range 2-6.5%) of absorbed CS2 was detected in urine as TTCA. The proportional TTCA excretion did not show dose dependency in the estimated CS2 dose range which varied by about 20-fold. TTCA elimination exhibited both a fast (T 1/2 6 hour) and a slow (T 1/2 68 hour) phase. The slow elimination is compatible with a high lipid solubility and reversible protein binding of CS2. Consequently, urinary excretion of TTCA, relative to CS2 exposure, increased by about a third during the workweek. Urinary TTCA concentration of 4.5 mmol/mol creatinine in a postshift sample corresponded to a TWA exposure to 10 ppm CS2 towards the end of the working week.

  2. Rapid adsorption of 2,4-dichlorophenoxyacetic acid by iron oxide nanoparticles-doped carboxylic ordered mesoporous carbon.

    Science.gov (United States)

    Tang, Lin; Zhang, Sheng; Zeng, Guang-Ming; Zhang, Yi; Yang, Gui-De; Chen, Jun; Wang, Jing-Jing; Wang, Jia-Jia; Zhou, Yao-Yu; Deng, Yao-Cheng

    2015-05-01

    The ordered mesoporous carbon composite functionalized with carboxylate groups and iron oxide nanoparticles (Fe/OMC) was successfully prepared and used to adsorb 2,4-dichlorophenoxyacetic acid (2,4-D) from wastewater. The resultant adsorbent possessed high degree of order, large specific surface area and pore volume, and good magnetic properties. The increase in initial pollutant concentration and contact time would make the adsorption capacity increase, but the pH and temperature are inversely proportional to 2,4-D uptake. The equilibrium of adsorption was reached within 120 min, and the equilibrated adsorption capacity increased from 99.38 to 310.78 mg/g with the increase of initial concentration of 2,4-D from 100 to 500 mg/L. Notablely, the adsorption capacity reached 97% of the maximum within the first 5 min. The kinetics and isotherm study showed that the pseudo-second-order kinetic and Langmuir isotherm models could well fit the adsorption data. These results indicate that Fe/OMC has a good potential for the rapid adsorption of 2,4-D and prevention of its further diffusion. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Saponin biosynthesis in Saponaria vaccaria. cDNAs encoding beta-amyrin synthase and a triterpene carboxylic acid glucosyltransferase.

    Science.gov (United States)

    Meesapyodsuk, Dauenpen; Balsevich, John; Reed, Darwin W; Covello, Patrick S

    2007-02-01

    Saponaria vaccaria (Caryophyllaceae), a soapwort, known in western Canada as cowcockle, contains bioactive oleanane-type saponins similar to those found in soapbark tree (Quillaja saponaria; Rosaceae). To improve our understanding of the biosynthesis of these saponins, a combined polymerase chain reaction and expressed sequence tag approach was taken to identify the genes involved. A cDNA encoding a beta-amyrin synthase (SvBS) was isolated by reverse transcription-polymerase chain reaction and characterized by expression in yeast (Saccharomyces cerevisiae). The SvBS gene is predominantly expressed in leaves. A S. vaccaria developing seed expressed sequence tag collection was developed and used for the isolation of a full-length cDNA bearing sequence similarity to ester-forming glycosyltransferases. The gene product of the cDNA, classified as UGT74M1, was expressed in Escherichia coli, purified, and identified as a triterpene carboxylic acid glucosyltransferase. UGT74M1 is expressed in roots and leaves and appears to be involved in monodesmoside biosynthesis in S. vaccaria.

  4. Binding of cyclic carboxylates to octa-acid deep-cavity cavitand

    Science.gov (United States)

    Gibb, Corinne L. D.; Gibb, Bruce C.

    2014-04-01

    As part of the fourth statistical assessment of modeling of proteins and ligands (sampl.eyesopen.com) prediction challenge, the strength of association of nine guests ( 1- 9) binding to octa-acid host was determined by a combination of 1H NMR and isothermal titration calorimetry. Association constants in sodium tetraborate buffered (pH 9.2) aqueous solution ranged from 5.39 × 102 M-1 in the case of benzoate 1, up to 3.82 × 105 M-1 for trans-4-methylcyclohexanoate 7. Overall, the free energy difference between the free energies of complexation of these weakest and strongest binding guests was ΔΔG° = 3.88 kcal mol-1. Based on a multitude of previous studies, the anticipated order of strength of binding was close to that which was actually obtained. However, the binding of guest 3 (4-ethylbenzoate) was considerably stronger than initially estimated.

  5. New γ -Lactone Carboxylic Acids from the Lichen Parmotrema praesorediosum (Nyl. Hale, Parmeliaceae

    Directory of Open Access Journals (Sweden)

    Bui Linh Chi Huynh

    2016-05-01

    Full Text Available From the lichen Parmotrema praesorediosum (Nyl. Hale, Parmeliaceae, collected in Vietnam, five new (1, 2, 3, 5, 6 and one known (4 g -lactonic acids were isolated. The structures of the new compounds were established by 1D and 2D NMR spectroscopy, as well as high resolution-electrospray ionization (HR-ESI-MS analysis. The absolute configuration of new compounds was determined by ultraviolet circular dichroism spectroscopy. Compounds were evaluated for their cytotoxic activity against HeLa (human epithelial carcinoma, NCI-H460 (human lung cancer and MCF-7 (human breast cancer cell lines at the concentration of 100 µg/mL. Among six compounds, 1 possessed medium activity against MCF-7 cell line with the inhibition of 52.5%. Meanwhile, the rest showed no cytotoxic activity against three surveyed cancer cell lines.

  6. Ionic networks derived from the protonation of dendritic amines with carboxylic acid end‐functionalized PEGs

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Skov, Anne Ladegaard; Hvilsted, Søren

    2013-01-01

    The synthesis and characterization of novel ionic networks linked by the ammonium salts of poly(propylene imine) (PPI) dendrimers of the first (PPI G1) and second (PPI G2) generation and two short bis carboxymethyl ether terminated poly(ethylene glycol)s (DiCOOH‐PEG) with different molecular...... weights (Mn ∼ 250 and Mn ∼ 600) are reported. Likewise, an ionic network based on PPI G1 and a long αω‐dicarboxylic acid functionalized PEG (Mn ∼ 4800) were evaluated. Simpler ionic structures based on tris(2‐aminoethyl)amine or hexamethylene diamine and the short DiCOOH‐PEGs are also investigated....... The ionic structures formed were confirmed by differential scanning calorimetry, Fourier Transform Infrared spectroscopy in the attenuated‐total‐reflection mode, and 1H‐13C NMR spectroscopy. A comprehensive 1H NMR analysis revealed that only the primary amines of the PPI G1 dendrimer residing...

  7. High fluorescence emission of carboxylic acid functionalized polystyrene/BaTiO{sub 3} nanocomposites and rare earth metal complexes: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cao, X. T.; Showkat, A. M.; Wang, Z.; Lim, K. T., E-mail: ktlim@pknu.ac.kr [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2015-03-30

    Noble fluorescence nanocomposite compound based on barium titanate nanoparticles (BTO), polystyrene (PSt), and terbium ion (Tb{sup 3+}) was synthesized by a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, Friedel-Crafts alkylation reaction and coordinate chemistry. Initially, a modification of surface of BTO was conducted by an exchange process with S-benzyl S’-trimethoxysilylpropyltrithiocarbonate to create macro-initiator for polymerization of styrene. Subsequently, aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-COOH) was generated by substitution reaction between 4-(Chloromethyl) benzoic acid and PSt chains. The coordination of the nanohybrids with Tb{sup 3+} ions afforded fluorescent Tb{sup 3+} tagged aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-Tb{sup 3+}) complexes. Structure, morphology, and fluorescence properties of nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR and SEM analyses confirmed the formation of BTO-g-PSt-Tb{sup 3+}nanohybrids. Furthermore, TGA profiles demonstrated the grafting of aryl carboxylic acid functionalized polystyrene on BTO surface. Optical properties of BTO-g-PSt-Tb{sup 3+} complexes were investigated by fluorescence spectroscopy.

  8. Antimicrobial activity of different sodium and potassium salts of carboxylic acid against some common foodborne pathogens and spoilage-associated bacteria.

    Science.gov (United States)

    Cabezas-Pizarro, Jorge; Redondo-Solano, Mauricio; Umaña-Gamboa, Christian; Arias-Echandi, María Laura

    Cleaning and disinfection represent the most important activities associated with the elimination of dirt and microorganisms at food processing plants. Improper procedures may lead to cross contamination of food leading to its spoilage or even the transmission of foodborne pathogens. Several strategies have been used in order to achieve a good disinfection of surfaces and products; nevertheless, microbial resistance to common-use-products has developed lately. Due to this fact, the development of new non-toxic-food compatible chemical agents that reduce the impact of foodborne pathogens and spoilage causing microorganisms is desirable for the food industry. The objective of the present study was to evaluate the antimicrobial activity of different sodium and potassium salts of aliphatic and aromatic carboxylic acid on the growth of common food spoilage and pathogenic microorganisms. Growth curves were determined for Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Salmonella Enteritidis, and Listeria monocytogenes in contact with different concentrations of carboxylic acid salts. The inhibitory effect of both aliphatic and aromatic carboxylic acid salts, in accordance with concentration levels, was 100>50>25mg/ml. The inhibitory effect of aliphatic salts was butanoic>hexanoic> octanoic>decanoic and, benzoic>gallic>caffeic acid salts for aromatic salts. In general, sodium salts were more inhibitory than potassium salts (p≤0.05). Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Antimicrobial activities, DNA interactions, spectroscopic (FT-IR and UV-Vis) characterizations, and DFT calculations for pyridine-2-carboxylic acid and its derivates

    Science.gov (United States)

    Tamer, Ömer; Tamer, Sevil Arabacı; İdil, Önder; Avcı, Davut; Vural, Hatice; Atalay, Yusuf

    2018-01-01

    In this paper, pyridine- 2- carboxylic acid, also known as picolinic acid (pic), and its two derivate, 4- methoxy-pyridine- 2- carboxylic acid (4-Mpic) and 4- chloro-pyridine- 2- carboxylic acid (4-Clpic) have been characterized by FT-IR and UV-Vis spectroscopy techniques as well as DFT calculations. B3LYP level of Density Functional Theory (DFT) method was used to obtain ground state geometries, vibration wavenumbers, first order hyperpolarizabilities and molecular electrostatic potential (MEP) surfaces for pic, 4Clpic and 4Mpic. The electronic absorption wavelengths and HOMO-LUMO energies were investigated by time dependent B3LYP (TD-B3LYP) level with the conductor-like polarizable continuum model (CPCM). The effects of Cl atom and OCH3 group on HOMO-LUMO energy gaps and first order hyperpolarizability parameters of pic, 4Clpic and 4Mpic molecules were examined. All molecules were screened for their antibacterial activities against Gram-positive and Gram-negative bacteria and for their antifungal activities against yeast strains by using minimal inhibitory concentration method (MIC). All compounds (pic, 4Mpic and 4Clpic) have been found to be very active against to the Gram (+) and Gram (-) bacteria. The DNA interactions of pic, 4Clpic and 4Mpic were analyzed by molecular docking simulations, and the interaction of the 4Mpic molecule with DNA is found to be higher than 4Clpic and pic.

  10. THz and mid-IR spectroscopy of interstellar ice analogs: methyl and carboxylic acid groups.

    Science.gov (United States)

    Ioppolo, S; McGuire, B A; Allodi, M A; Blake, G A

    2014-01-01

    A fundamental problem in astrochemistry concerns the synthesis and survival of complex organic molecules (COMs) throughout the process of star and planet formation. While it is generally accepted that most complex molecules and prebiotic species form in the solid phase on icy grain particles, a complete understanding of the formation pathways is still largely lacking. To take full advantage of the enormous number of available THz observations (e.g., Herschel Space Observatory, SOFIA, and ALMA), laboratory analogs must be studied systematically. Here, we present the THz (0.3-7.5 THz; 10-250 cm(-1)) and mid-IR (400-4000 cm(-1)) spectra of astrophysically-relevant species that share the same functional groups, including formic acid (HCOOH) and acetic acid (CH3COOH), and acetaldehyde (CH3CHO) and acetone ((CH3)2CO), compared to more abundant interstellar molecules such as water (H2O), methanol (CH3OH), and carbon monoxide (CO). A suite of pure and mixed binary ices are discussed. The effects on the spectra due to the composition and the structure of the ice at different temperatures are shown. Our results demonstrate that THz spectra are sensitive to reversible and irreversible transformations within the ice caused by thermal processing, suggesting that THz spectra can be used to study the composition, structure, and thermal history of interstellar ices. Moreover, the THz spectrum of an individual species depends on the functional group(s) within that molecule. Thus, future THz studies of different functional groups will help in characterizing the chemistry and physics of the interstellar medium (ISM).

  11. Thermal pretreatment of olive mill wastewater for efficient methane production: control of aromatic substances degradation by monitoring cyclohexane carboxylic acid.

    Science.gov (United States)

    Pontoni, Ludovico; d'Antonio, Giuseppe; Esposito, Giovanni; Fabbricino, Massimiliano; Frunzo, Luigi; Pirozzi, Francesco

    2015-01-01

    Anaerobic digestion is investigated as a sustainable depurative strategy of olive oil mill wastewater (OOMW). The effect of thermal pretreatment on the anaerobic biodegradation of aromatic compounds present in (OMWW) was investigated. The anaerobic degradation of phenolic compounds, well known to be the main concern related to this kind of effluents, was monitored in batch anaerobic tests at a laboratory scale on samples pretreated at mild (80±1 °C), intermediate (90±1 °C) and high temperature (120±1 °C). The obtained results showed an increase of 34% in specific methane production (SMP) for OMWW treated at the lowest temperature and a decrease of 18% for treatment at the highest temperature. These results were related to the different decomposition pathways of the lignocellulosic compounds obtained in the tested conditions. The decomposition pathway was determined by measuring the concentrations of volatile organic acids, phenols, and chemical oxygen demand (COD) versus time. Cyclohexane carboxylic acid (CHCA) production was identified in all the tests with a maximum concentration of around 200 µmol L(-1) in accordance with the phenols degradation, suggesting that anaerobic digestion of aromatic compounds follows the benzoyl-CoA pathway. Accurate monitoring of this compound was proposed as the key element to control the process evolution. The total phenols (TP) and total COD removals were, with SMP, the highest (TP 62.7%-COD 63.2%) at 80 °C and lowest (TP 44.9%-COD 32.2%) at 120 °C. In all cases, thermal pretreatment was able to enhance the TP removal ability (up to 42% increase).

  12. Synthesis, characterization and crystal structure of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid

    Science.gov (United States)

    Muche, Simon; Müller, Matthias; Hołyńska, Małgorzata

    2018-03-01

    The condensation reaction of ortho-vanillin and L-cysteine leads to formation of a racemic mixture of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid and not, as reported in the available literature, to a Schiff base. The racemic mixture was fully characterized by 1D and 2D NMR techniques, ESI-MS and X-ray diffraction. Addition of ZnCl2 led to formation of crystals in form of colorless needles, suitable for X-ray diffraction studies. The measured crystals were identified as the diastereomer (2R,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid 1. The bulk material is racemic. Thiazolidine exists as zwitterion in solid state, as indicated by the crystal structure.

  13. Synthetic applications of Pd(II)-catalyzed C-H carboxylation and mechanistic insights: expedient routes to anthranilic acids, oxazolinones, and quinazolinones.

    Science.gov (United States)

    Giri, Ramesh; Lam, Jonathan K; Yu, Jin-Quan

    2010-01-20

    A Pd(II)-catalyzed reaction protocol for the carboxylation of ortho-C-H bonds in anilides to form N-acyl anthranilic acids has been developed. This reaction procedure provides a novel and efficient strategy for the rapid assembly of biologically and pharmaceutically significant molecules, such as benzoxazinones and quinazolinones, from simple anilides without installing and removing an external directing group. The reaction conditions are also amenable to the carboxylation of N-phenyl pyrrolidinones. A monomeric palladacycle containing p-toluenesulfonate as an anionic ligand has been characterized by X-ray crystallography, and the crucial role of p-toluenesulfonic acid in the activation of C-H bonds in the presence of carbon monoxide is discussed. Identification of two key intermediates, a mixed anhydride and benzoxazinone formed by reductive elimination from organometallic Ar(CO)Pd(II)-OTs species, provides mechanistic evidence for a dual-reaction pathway.

  14. Effects of humic acid and solution chemistry on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles

    Science.gov (United States)

    Hwang, G.; Gomez-Flores, A.; Choi, S.; Han, Y., , Dr; Kim, H.

    2017-12-01

    The influence of humic acid, ionic strength and ionic species on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles (CB-NPs) was systemically investigated in aqueous media. The experimental conditions of stability tests were selected to the changes in the solution chemistry (0.1-10 mM NaCl and 0.01-1 mM CaCl2) and in the presence/absence of humic acid (1 and 5 mg L-1) in an aquatic environment. The CB-NPs suspension was more rapidly settled in NaCl solution than in CaCl2. Specifically, in the case of NaCl, the aggregation rate of CB-NPs increased with ionic strength. Contrary, CB-NPs dispersed in CaCl2 were insensitive to the aggregation as the ionic strength increased; that was because specific adsorption of the divalent cation Ca2+ occurred since the zeta potential of the CB-NPs is reversed to a positive charge with increasing of the ionic strength. It was confirmed that humic acid greatly influences the stability of the CB-NPs. In particular, the dispersion of CB-NPs was improved in the whole range of ionic strengths of NaCl as well as of CaCl2. To support the results, the interaction energy between CB-NPs was calculated for each condition by using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and modified-DLVO theories. In the presence of humic acid, the improved stability of CB-NPs is attributed to the steric repulsive force.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01020766), the Ministry of Education (MOE) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation (2015H1C1A1035930) and Korea Energy and Mineral Resources Engineering Program (KEMREP).

  15. Synthesis and characterization of acidic mesoporous borosilicate thin films.

    Science.gov (United States)

    Xiu, Tongping; Liu, Qian; Wang, Jiacheng

    2009-02-01

    Work on the synthesis and characterization of acidic wormhole-like ordered mesoporous borosilicate thin films (MBSTFs) on silicon wafers is described in this paper. The MBSTFs coated by the dip-coating method were prepared through an evaporation-induced self-assembly (EISA) process using nonionic block copolymers as structure-directing agents. Fourier transform infrared (FT-IR) spectroscopy confirmed the formation of borosiloxane bonds (Si-O-B). High-resolution transmission electron microscopy (HRTEM) and N2 sorption evidenced a wormhole-like mesoporous structure in the MBSTFs obtained. Scanning electron microscopy (SEM) images of the cross sections and surfaces of the samples showed that MBSTFs on silicon wafers were continuous, homogeneous and did not crack. The acidic properties of the MBSTFs were characterized by FT-IR spectra of chemisorbed pyridine. The MBSTFs thus prepared may find their future applications in many fields including chemical sensors, catalysis, optical coating, molecule separation, etc.

  16. Determination of carboxylic acids, carbohydrates and metals in different tomato cultivars by HPLC-ICP-AES in a single chromatographic run

    OpenAIRE

    Paredes Paredes, Eduardo; Maestre, Salvador E.; Prats Moya, Soledad; Todolí Torró, José Luis

    2007-01-01

    Póster presentado en European Winter Conference on Plasma Spectrochemistry 2007, 18-23 February 2007, Taormina, Italy The determination of carbohydrates, carboxylic acids and metals is a subject of great interest in the field of food science because their presence and concentration can influence on food quality. Besides the study of the profiles of these compounds can permit the discrimination between different varieties of a product. Unfortunately, the usually employed chromatograph...

  17. Self-assembled thiol monolayers with carboxylic acid functionality: Measuring pH-dependent phase transitions with the quartz crystal microbalance

    International Nuclear Information System (INIS)

    Wang, J.; Frostman, L.M.; Ward, M.D.

    1992-01-01

    The resonant frequency of the quartz crystal microbalance (QCM) coated with self-assembled thiol monolayers with carboxylic acid functionality is measured while the pH of the aqueous solvent is changed in this paper. Increased tensile stress with increasing pH activity partially contributed to the QCM response, but the major contribution was due to changes in the viscoelastic properties of the hydrodynamic layer in contact with the QCM. 28 refs., 3 figs

  18. Cofactor Balance by Nicotinamide Nucleotide Transhydrogenase (NNT) Coordinates Reductive Carboxylation and Glucose Catabolism in the Tricarboxylic Acid (TCA) Cycle*♦

    Science.gov (United States)

    Gameiro, Paulo A.; Laviolette, Laura A.; Kelleher, Joanne K.; Iliopoulos, Othon; Stephanopoulos, Gregory

    2013-01-01

    Cancer and proliferating cells exhibit an increased demand for glutamine-derived carbons to support anabolic processes. In addition, reductive carboxylation of α-ketoglutarate by isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) was recently shown to be a major source of citrate synthesis from glutamine. The role of NAD(P)H/NAD(P)+ cofactors in coordinating glucose and glutamine utilization in the tricarboxylic acid (TCA) cycle is not well understood, with the source(s) of NADPH for the reductive carboxylation reaction remaining unexplored. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial enzyme that transfers reducing equivalents from NADH to NADPH. Here, we show that knockdown of NNT inhibits the contribution of glutamine to the TCA cycle and activates glucose catabolism in SkMel5 melanoma cells. The increase in glucose oxidation partially occurred through pyruvate carboxylase and rendered NNT knockdown cells more sensitive to glucose deprivation. Importantly, knocking down NNT inhibits reductive carboxylation in SkMel5 and 786-O renal carcinoma cells. Overexpression of NNT is sufficient to stimulate glutamine oxidation and reductive carboxylation, whereas it inhibits glucose catabolism in the TCA cycle. These observations are supported by an impairment of the NAD(P)H/NAD(P)+ ratios. Our findings underscore the role of NNT in regulating central carbon metabolism via redox balance, calling for other mechanisms that coordinate substrate preference to maintain a functional TCA cycle. PMID:23504317

  19. Efficient and convenient synthesis of symmetrical carboxylic ...

    African Journals Online (AJOL)

    An efficient and convenient procedure for the synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by PEG-1000 phase transfer catalysis has been developed. The reactions proceeded under mild and solvent-free conditions to provide the carboxylic anhydrides in good to excellent ...

  20. Structure-Activity Relationship Study of Ionotropic Glutamate Receptor Antagonist (2S,3R)-3-(3-Carboxyphenyl)pyrrolidine-2-carboxylic Acid

    DEFF Research Database (Denmark)

    Krogsgaard-Larsen, Niels; Storgaard, Morten; Møller, Charlotte

    2015-01-01

    Herein we describe the first structure-activity relationship study of the broad-range iGluR antagonist (2S,3R)-3-(3-carboxyphenyl)pyrrolidine-2-carboxylic acid (1) by exploring the pharmacological effect of substituents in the 4, 4', or 5' positions and the bioisosteric substitution of the distal...... carboxylic acid for a phosphonic acid moiety. Of particular interest is a hydroxyl group in the 4' position 2a which induced a preference in binding affinity for homomeric GluK3 over GluK1 (Ki = 0.87 and 4.8 μM, respectively). Two X-ray structures of ligand binding domains were obtained: 2e in GluA2-LBD...... and 2f in GluK1-LBD, both at 1.9 Å resolution. Compound 2e induces a D1-D2 domain opening in GluA2-LBD of 17.3-18.8° and 2f a domain opening in GluK1-LBD of 17.0-17.5° relative to the structures with glutamate. The pyrrolidine-2-carboxylate moiety of 2e and 2f shows a similar binding mode as kainate...

  1. 1-Azaniumylcyclobutane-1-carboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    Ray J. Butcher

    2014-02-01

    Full Text Available In the title compound, C5H9NO2·H2O, the amino acid is in the usual zwitterionic form involving the α-carboxylate group. The cyclobutane backbone of the amino acid is disordered over two conformations, with occupancies of 0.882 (7 and 0.118 (7. In the crystal, N—H...O and O—H...O hydrogen bonds link the zwitterions [with the water molecule involved as both acceptor (with the NH3+ and donor (through a single carboxylate O from two different aminocyclobutane carboxylate moities], resulting in a two-dimensional layered structure lying parallel to (100.

  2. Cyanide toxicokinetics: the behavior of cyanide, thiocyanate and 2-amino-2-thiazoline-4-carboxylic acid in multiple animal models.

    Science.gov (United States)

    Bhandari, Raj K; Oda, Robert P; Petrikovics, Ilona; Thompson, David E; Brenner, Matthew; Mahon, Sari B; Bebarta, Vikhyat S; Rockwood, Gary A; Logue, Brian A

    2014-05-01

    Cyanide causes toxic effects by inhibiting cytochrome c oxidase, resulting in cellular hypoxia and cytotoxic anoxia, and can eventually lead to death. Cyanide exposure can be verified by direct analysis of cyanide concentrations or analyzing its metabolites, including thiocyanate (SCN(-)) and 2-amino-2-thiazoline-4-carboxylic acid (ATCA) in blood. To determine the behavior of these markers following cyanide exposure, a toxicokinetics study was performed in three animal models: (i) rats (250-300 g), (ii) rabbits (3.5-4.2 kg) and (iii) swine (47-54 kg). Cyanide reached a maximum in blood and declined rapidly in each animal model as it was absorbed, distributed, metabolized and eliminated. Thiocyanate concentrations rose more slowly as cyanide was enzymatically converted to SCN(-). Concentrations of ATCA did not rise significantly above the baseline in the rat model, but rose quickly in rabbits (up to a 40-fold increase) and swine (up to a 3-fold increase) and then fell rapidly, generally following the relative behavior of cyanide. Rats were administered cyanide subcutaneously and the apparent half-life (t1/2) was determined to be 1,510 min. Rabbits were administered cyanide intravenously and the t1/2 was determined to be 177 min. Swine were administered cyanide intravenously and the t1/2 was determined to be 26.9 min. The SCN(-) t1/2 in rats was 3,010 min, but was not calculated in rabbits and swine because SCN(-) concentrations did not reach a maximum. The t1/2 of ATCA was 40.7 and 13.9 min in rabbits and swine, respectively, while it could not be determined in rats with confidence. The current study suggests that cyanide exposure may be verified shortly after exposure by determining significantly elevated cyanide and SCN(-) in each animal model and ATCA may be used when the ATCA detoxification pathway is significant.

  3. Establishment of the measurement uncertainty of 11-nor-D9-tetrahydrocannabinol-9-carboxylic acid in hair.

    Science.gov (United States)

    Han, Eunyoung; Yang, Wonkyung; Lee, Sooyeun; Kim, Eunmi; In, Sangwhan; Choi, Hwakyung; Lee, Sangki; Chung, Heesun; Song, Joon Myong

    2011-03-20

    The quantitative analysis of 11-nor-D(9)-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in hair requires a sensitive method to detect a low-pg level. Before applying the method to real hair samples, the method was validated; in this study, we examined the uncertainty obtained from around the cut-off level of THCCOOH in hair. We calculated the measurement uncertainty (MU) of THCCOOH in hair as follows: specification of the measurand, identification of parameters using "cause and effect" diagrams, quantification of the uncertainty contributions using three factors, the uncertainty of weighing the hair sample, the uncertainty from calibrators and the calibration curve, and the uncertainty of the method precision. Finally, we calculated the degrees of freedom and the expanded uncertainty (EU). The concentration of THCCOOH in the hair sample with its EU was (0.60 ± 0.1) × 10(-4)ng/mg. The relative uncertainty percent for the measurand 0.60 × 10(-4)ng was 9.13%. In this study, we also selected different concentrations of THCCOOH in real hair samples and then calculated the EU, the relative standard uncertainty (RSU) of the concentration of THCCOOH in the test sample [u(r)(c0)], the relative uncertainty percent, and the effective degree of freedom (v(eff)). When the concentrations of THCCOOH approached the cut-off level, u(r)(c0) and the relative uncertainty percent increased but absolute EU and v(eff) decreased. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  4. On the microstructure of organic solutions of mono-carboxylic acids: Combined study by infrared spectroscopy, small-angle neutron scattering and molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Eremin, Roman A., E-mail: era@jinr.ru [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kholmurodov, Kholmirzo T. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); International University “Dubna”, Dubna 141980 (Russian Federation); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv 03022 (Ukraine); Rosta, László [Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest H-1525 (Hungary); Grigoryeva, Natalia A. [Faculty of Physics, Saint-Petersburg State University, 198504 Saint-Petersburg (Russian Federation); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

    2015-11-05

    Highlights: • The model of the scattering particle for a reliable SANS analysis is proposed. • The structural parameters of saturated mono-carboxylic acids in solutions are obtained. • The differences in nematic transitions correlate to solvation peculiarities. - Abstract: The data of infrared spectroscopy (IR), molecular dynamics (MD) simulations and small-angle neutron scattering (SANS) have been combined to conclude about the nanoscale structural organization of organic non-polar solutions of saturated mono-carboxylic acids with different alkyl chain lengths for diluted solutions of saturated myristic (C14) and stearic (C18) acids in benzene and decalin. In particular, the degree of dimerization was found from the IR spectra. The structural anisotropy of the acids and their dimers was used in the treatment of the data of MD simulations to describe the solute–solvent interface in a cylindrical approximation and show its rather strong influence on SANS. The corresponding scattering length density profiles were used to fit the experimental SANS data comprising the information about the acid molecule isomerization. The SANS data from concentrated solutions showed a partial self-assembling of the acids within the nematic transition is different for two solvents due to lyophobic peculiarities.

  5. 4-Methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic Acid. Peculiarities of Preparation, Structure, and Biological Properties

    Directory of Open Access Journals (Sweden)

    Igor V. Ukrainets

    2018-03-01

    Full Text Available In order to determine the regularities of the structure–analgesic activity relationship, the peculiarities of obtaining, the spatial structure, and biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and some of its derivatives have been studied. Using nuclear magnetic resonance (NMR spectroscopy and X-ray diffraction analysis, it has been proven that varying the reaction conditions using alkaline hydrolysis of methyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate makes it possible to successfully synthesize a monohydrate of the target acid, its sodium salt, or 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine. The derivatographic study of the thermal stability of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid monohydrate has been carried out; based on this study, the optimal conditions completely eliminating the possibility of unwanted decomposition have been proposed for obtaining its anhydrous form. It has been shown that 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine is easily formed during the decarboxylation of not only 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid, but also its sodium salt, which is capable of losing СО2 both in rather soft conditions of boiling in an aqueous solution, and in more rigid conditions of dry heating. The NMR spectra of the compounds synthesized are given; their spatial structure is discussed. To study the biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and its sodium salt, the experimental model of inflammation caused by subplantar introduction of the carrageenan solution in one of the hind limbs of white rats was used. The anti-inflammatory activity and analgesic effect were assessed by the degree of edema reduction and the ability to affect the pain response compared to the animals of control groups. According to the results of the tests performed, it has been found that after intraperitoneal injection

  6. Effects of aminoisobutyric acid on 1-aminocyclopropane-1-carboxylic acid uptake, ethylene production and content of ACC in water-stressed tomato plants

    International Nuclear Information System (INIS)

    Kalantari, Kh.M.; Bolourani, P.

    2000-01-01

    The effect of water stress on the regulation of ethylene biosynthesis has not yet clearly been established. Both the formation and utilization of aminocyclopropane-1-carboxylic acid, ACC, are considered to be major regulatory points in ethylene biosynthesis. There is evidence that ACC synthase is the key control enzyme in response to various stimuli associated with the induction of ethylene biosynthesis. It has been reported that aminoisobutyric acid, AIB, inhibits ethylene production in some plants and AIB may inhibit the conversion of ACC to ethylene. For this reason, the possibility of inhibition of ACC uptake in the presence of AIB was examined. It was observed that the rate of 14 C-ACC uptake decreased with an increase in the concentration of AIB in the solution. Calculating the percentage of ACC converted to ethylene on the basis of uptake shows that AIB inhibits the conversion of 14 C-ACC to ethylene and that this inhibition is increased with an increase in the concentration of AIB in the solution. This suggests that a portion of the inhibition of the conversion of ACC to ethylene in the presence of AIB is partly due to the competition for absorption. However, the ability of AIB to inhibit ethylene production in leaf tissue without an exogenous supply of ACC clearly indicates that AIB inhibits ethylene production. The present study was undertaken to elucidate the regulation of ethylene biosynthesis in water-stressed plants and the results are discussed

  7. Discovery of a New Class of Ionotropic Glutamate Receptor Antagonists by the Rational Design of (2S,3R)-3-(3-Carboxyphenyl)-pyrrolidine-2-carboxylic Acid

    DEFF Research Database (Denmark)

    Larsen, Ann Møller; Venskutonyte, Raminta; Valadés, Elena Antón

    2011-01-01

    The kainic acid (KA) receptors belong to the class of glutamate (Glu) receptors in the brain and constitute a promising target for the treatment of neurological and/ or psychiatric diseases such as schizophrenia, major depression, and epilepsy. Five KA subtypes have been identified and named GluK1......-5. In this article, we present the discovery of (2S,3R)-3-(3-carboxyphenyl)-pyrrolidine-2-carboxylic acid (1) based on a rational design process. Target compound 1 was synthesized by a stereoselective strategy in 10 steps from commercially available starting materials. Binding affinities of 1 at native ionotropic...

  8. Analysis of tellurium thin films electrodeposition from acidic citric bath

    Energy Technology Data Exchange (ETDEWEB)

    Kowalik, Remigiusz; Kutyła, Dawid [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Mech, Krzysztof [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, al. A. Mickiewicza 30, Krakow (Poland); Żabiński, Piotr, E-mail: rkowalik@agh.edu.pl [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland)

    2016-12-01

    This work presents the description of the electrochemical process of formation thin tellurium layers from citrate acidic solution. The suggested methodology consists in the preparation of stable acidic baths with high content of tellurium, and with the addition of citrate acid. In order to analyse the mechanism of the process of tellurium deposition, the electroanalytical tests were conducted. The tests of cyclic voltammetry and hydrodynamic ones were performed with the use of polycrystalline gold disk electrode. The range of potentials in which deposition of tellurium in direct four-electron process is possible was determined as well as the reduction of deposited Te° to Te{sup 2−} and its re-deposition as a result of the comproportionation reaction. On the basis of the obtained results, the deposition of tellurium was conducted by the potentiostatic method. The influence of a deposition potential and a concentration of TeO{sub 2} in the solution on the rate of tellurium coatings deposition was examined. The presence of tellurium was confirmed by X-ray spectrofluorometry and electron probe microanalysis. In order to determine the phase composition and the morphology, the obtained coatings were analysed with the use of x-ray diffraction and scanning electron microscopy.

  9. Fe(II) and Co (II) complexes of (4-(4-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid) synthesis, characterization and electrochromic studies

    International Nuclear Information System (INIS)

    Saba, A.; Maqsood, Z.T.; Wasim, A.A.; Basha, F.Z.

    2017-01-01

    In this study novel complexes of substituted bipyridine (4-(4-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid) with Fe/sup +2/ and Co/sup +2/ were synthesized and characterized by different physical, analytical and spectral techniques which includes /sup 1/ H-NMR, MALDI-MS, FTIR, UV-VIS Spectrophotometry, CHN analysis and conductometry. Mole ratio method revealed that both complexes satisfied ML2 stoichiometry. Other characterization studies showed that substituted bipyridine acted as a tridentate ligand, with two pyridine N and one carboxylic O atom as binding sites per ligand molecule. The complexes were found octahedral, neutral and possessed fairly high molar absorptivities in visible region. Electrochromic studies revealed that Fe (II) complex had relatively good electrochromic properties with a reversible color change from blue to pale yellow. Co (II) complex, however, did not show significant electrochromic properties in the visible region. (author)

  10. Absolute configuration determination of the anti-head-to-head photocyclodimer of anthracene-2-carboxylic acid through cocrystallization with L-prolinol.

    Science.gov (United States)

    Kawanami, Yuko; Tanaka, Hidekazu; Mizoguchi, Jun-ichi; Kanehisa, Nobuko; Fukuhara, Gaku; Nishijima, Masaki; Mori, Tadashi; Inoue, Yoshihisa

    2013-11-01

    The absolute configuration has been established of the enantiopure anti-head-to-head cyclodimer of anthracene-2-carboxylic acid (AC) cocrystallized with L-propinol and dichloromethane [systematic name: (S)-2-(hydroxymethyl)pyrrolidin-1-ium (5R,6S,11R,12S)-8-carboxy-5,6,11,12-tetrahydro-5,12:6,11-bis([1,2]benzeno)dibenzo[a,e][8]annulene-2-carboxylate dichloromethane monosolvate], C5H12NO(+)·C30H19O4(-)·CH2Cl2. In the crystal structure, the AC dimer interacts with L-prolinol through a nine-membered hydrogen-bonded ring [R2(2)(9)], while the dichloromethane molecule is incorporated to fill the void space. The absolute configuration determined in this study verifies a recent assignment made by comparing theoretical versus experimental circular dichroism spectra.

  11. A facile and novel approach towards carboxylic acid functionalization of multiwalled carbon nanotubes and efficient water dispersion

    KAUST Repository

    Rehman, Ata Ur

    2013-10-01

    A convenient, cheap and mild covalent functionalization route for multiwalled carbon nanotubes (MWCNTs) have been developed for the first time. The MWCNTs were treated with wet chemical oxidants (NaNO2/HCl, HNO3/H2O2) in order to modify MWCNTs with carboxyl groups. Surface functionality groups and morphology of MWCNTs were analyzed by FTIR, TGA, SEM and TEM. The results consistently confirmed the formation of carboxyl functionalities on MWCNTs, while the structure of MWCNTs has remained relatively intact. Functionalized MWCNTs showed good dispersion in aqueous media than untreated MWCNTs. Results show that NaNO2/HCl treatment is best suited for the chemical functionalization, giving optimum surface carboxyl groups and minimum length shortening of MWCNTs. © 2013 Elsevier B.V.

  12. Protective effect of chelating agents of catechols amino carboxylic acid on radiation injury induced by radiothorium in mice: prompt administration

    International Nuclear Information System (INIS)

    Chen Honghong; Hu Yuxing; Wang Yinghua; Jin Meiying; Luo Meishu; Sun Meizhen

    2003-01-01

    Objective: To study decorporation and antioxidation efficacy of chelating agents (9501 and 7601) of the substituted catechols amino carboxylic acid for radiothorium in vivo. Methods: The experiment was first designed to find out the dose and time of radiation injury by incorporated 234 Th-citrate in ICR mice. The malondialdehyde (MDA) production serving as an index of 234 Th-induced lipid peroxidation in bone marrow, serum and liver of mice was assayed and the numbers of bone marrow nucleated cells (NBMNC) were counted. The pathological changes of bone marrow and liver tissue were observed. The chelating agents were promptly administered im to mice for three consecutive days after ip injection of 0.6 MBq 234 Th-citrate. The animals were sacrificed 4 days later and the 234 Th retention in the whole body, liver and skeleton and the above indexes were determined. Results: The mice showed significantly internal radiation injury of bone marrow and liver at 4th to 8th after ip injection of 0.6 MBq 234 Th-citrate. The prompt administration of 9501,7601 and DTPA decreased the whole body radioactivity by 81%, 86% and 72%, respectively, as compared with those of the control group. The sum of retention of 234 Th in liver and skeleton was reduced to 22%, 21% and 58% of controls, respectively. The removal efficacy of 9501 and 7601 was better than that of DTPA. The NBMNC, contents of MDA in bone marrow and the structure of bone marrow and liver tissue didn't show any abnormality in 9501 and 7601 groups. DTPA appeared to have a lower protective effectiveness on radiation injury of bone marrow. VitE had no decorporation activity and didn't alleviate radiotoxicity. The combined use of DTPA and VitE showed both decorporation effect of DTPA and antioxidation effect of VitE. Conclusion: The prompt administration of 9501 and 7601 has remarkable protective effects on internal radiation injury, which resulting from decorporation activity and conceal their antioxidation

  13. Development of starch biofilms using different carboxylic acids as plasticizers; Desenvolvimento de biofilmes de amido utilizando como plastificantes diferentes acidos carboxilicos

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, L.C.; Miranda, C.S.; Santos, W.J. dos; Goncalves, A.P.B.; Oliveira, J.C.; Jose, N.M., E-mail: uanaconceicaocruz@gmail.com [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Grupo de Energia e Ciencias dos Materiais

    2014-07-01

    Biodegradable films have become a widely exploited issue among scientists because of their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life. Starch has been studied in this field due to its availability, low cost and biodegradability. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids chain size in the final films properties. The acids used were: oxalic, succinic and adipic. The materials were produced by casting and characterized by DSC, TG, DRX e FTIR. It was observed that the acids chain size influenced on the thermal and structural properties of the films. (author)

  14. Crystal structure of 7,7-dimethyl-6-methylidenetricyclo[6.2.1.01,5]undecane-2-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Noureddine Beghidja

    2015-02-01

    Full Text Available In the title compound, C15H22O2, both five-membered rings display an envelope conformation whereas the six-membered ring displays a chair conformation. In the crystal, pairs of O—H...O hydrogen bonds between carboxylic groups link molecules, related by a twofold rotation axis, into supramolecular dimers.

  15. In situ SERS and X-ray photoelectron spectroscopy studies on the pH-dependant adsorption of anthraquinone-2-carboxylic acid on silver electrode

    Science.gov (United States)

    Li, Dan; Jia, Shaojie; Fodjo, Essy Kouadio; Xu, Hu; Wang, Yuhong; Deng, Wei

    2016-03-01

    In this study, in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) are used to investigate the redox reaction and adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on an Ag electrode at different pH values. The obtained results indicate that AQ-2-COOH is adsorbed tilted on the Ag electrode through O-atom of ring carbonyl in a potential range from -0.3 to -0.5 V vs. SCE, but the orientation turns to more tilted orientation with both O-atom of the ring carbonyl and carboxylate group in positive potential region for pH 6.0 and 7.4. However, at pH 10.0, the orientation adopts tilted conformation constantly on the Ag electrode with both O-atom of the anthraquinone ring and carboxylate group in the potential range from -0.3 to -0.5 V vs. SCE or at positive potentials. Moreover, the adsorption behavior of AQ-2-COOH has been further confirmed by AR-XPS on the Ag surface. Proposed reasons for the observed changes in orientation are presented.

  16. Halogen-induced organic aerosol (XOA) formation and decarboxylation of carboxylic acids by reactive halogen species - a time-resolved aerosol flow-reactor study

    Science.gov (United States)

    Ofner, Johannes; Zetzsch, Cornelius

    2013-04-01

    Reactive halogen species (RHS) are released to the atmosphere from various sources like photo-activated sea-salt aerosol and salt lakes. Recent studies (Cai et al., 2006 and 2008, Ofner et al., 2012) indicate that RHS are able to interact with SOA precursors similarly to common atmospheric oxidizing gases like OH radicals and ozone. The reaction of RHS with SOA precursors like terpenes forms so-called halogen-induced organic aerosol (XOA). On the other hand, RHS are also able to change the composition of functional groups, e.g. to initiate the decarboxylation of carboxylic acids (Ofner et al., 2012). The present study uses a 50 cm aerosol flow-reactor, equipped with a solar simulator to investigate the time-resolved evolution and transformation of vibrational features in the mid-infrared region. The aerosol flow-reactor is coupled to a home-made multi-reflection cell (Ofner et al., 2010), integrated into a Bruker IFS 113v FTIR spectrometer. The reactor is operated with an inlet feed (organic compound) and a surrounding feed (reactive halogen species). The moveable inlet of the flow reactor allows us to vary reaction times between a few seconds and up to about 3 minutes. Saturated vapours of different SOA precursors and carboxylic acids were fed into the flow reactor using the moveable inlet. The surrounding feed inside the flow reactor was a mixture of zero air with molecular chlorine as the precursor for the formation of reactive halogen species. Using this setup, the formation of halogen-induced organic aerosol could be monitored with a high time resolution using FTIR spectroscopy. XOA formation is characterized by hydrogen-atom abstraction, carbon-chlorine bond formation and later, even formation of carboxylic acids. Several changes of the entire structure of the organic precursor, caused by the reaction of RHS, are visible. While XOA formation is a very fast process, the decarboxylation of carboxylic acids, induced by RHS is rather slow. However, XOA formation

  17. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds.

    Science.gov (United States)

    Hermann, Katrin; Meinhard, Juliane; Dobrev, Peter; Linkies, Ada; Pesek, Bedrich; Hess, Barbara; Machácková, Ivana; Fischer, Uwe; Leubner-Metzger, Gerhard

    2007-01-01

    The control of sugar beet (Beta vulgaris L.) germination by plant hormones was studied by comparing fruits and seeds. Treatment of sugar beet fruits and seeds with gibberellins, brassinosteroids, auxins, cytokinins, and jasmonates or corresponding hormone biosynthesis inhibitors did not appreciably affect radicle emergence of fruits or seeds. By contrast, treatment with ethylene or the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) promoted radicle emergence of fruits and seeds. Abscisic acid (ABA) acted as an antagonist of ethylene and inhibited radicle emergence of seeds, but not appreciably of fruits. High endogenous contents of ACC and of ABA were evident in seeds and pericarps of dry mature fruits, but declined early during imbibition. ABA-treatment of seeds and fruits induced seed ACC accumulation while ACC-treatment did not affect the seed ABA content. Transcripts of ACC oxidase (ACO, ethylene-forming enzyme) and ABA 8'-hydroxylase (CYP707A, ABA-degrading enzyme) accumulate in fruits and seeds upon imbibition. ABA and ACC and the pericarp did not affect the seed CYP707A transcript levels. By contrast, seed ACO transcript accumulation was promoted by ABA and by pericarp removal, but not by ACC. Quantification of the endogenous ABA and ACC contents, ABA and ACC leaching, and ethylene evolution, demonstrate that an embryo-mediated active ABA extrusion system is involved in keeping the endogenous seed ABA content low by 'active ABA leaching', while the pericarp restricts ACC leaching during imbibition. Sugar beet radicle emergence appears to be controlled by the pericarp, by ABA and ACC leaching, and by an ABA-ethylene antagonism that affects ACC biosynthesis and ACO gene expression.

  18. Long-chain perfluoroalkyl carboxylic acids in Pacific cods from coastal areas in northern Japan: A major source of human dietary exposure

    International Nuclear Information System (INIS)

    Fujii, Yukiko; Sakurada, Tsukasa; Harada, Kouji H.; Koizumi, Akio; Kimura, Osamu; Endo, Tetsuya; Haraguchi, Koichi

    2015-01-01

    This study investigates perfluoroalkyl carboxylic acids (PFCAs) contamination of edible fish muscle from Japanese coastal waters. The concentrations of PFCAs with 8–14 carbon atoms (C8–C14) in Pacific cods in Hokkaido, Japan were 51 (median: pg/g-wet weight) for C8, 93 for C9, 99 for C10, 746 for C11, 416 for C12, 404 for C13, and 93 for C14. The levels of C9–C14 PFCAs in fish were strongly correlated to each other, but not to C8 and the other chlorinated persistent organic pollutants, indicating that C9–C14 PFCAs have a different emission source and/or bioaccumulation mechanism. The relative ratios between estimated PFCAs intake through fish consumption and the reported total dietary exposure of PFCAs were less than 1 for C8 to C9, but were more than 1 for C10 to C14. This result strongly suggests that fish consumption is a significant source of human dietary exposure to C10–C14 PFCAs. - Highlights: • Perfluoroalkyl carboxylic acids were detected in edible cod fish from Japanese coastal waters. • The levels of long-chain PFCAs in fish were independent from those of C8 and other POPs. • Long chain PFCAs intake through fish and the reported total dietary exposure were comparable. • Sea fish such as Pacific cod may be a significant human dietary source of long-chain PFCAs. - Sea fish are a significant source of long-chain perfluoroalkyl carboxylic acids for the Japanese population

  19. Molecular level computational studies of polyethylene and polyacrylonitrile composites containing single walled carbon nanotubes: effect of carboxylic acid functionalization on nanotube-polymer interfacial properties.

    Science.gov (United States)

    Haghighatpanah, Shayesteh; Bohlén, Martin; Bolton, Kim

    2014-01-01

    Molecular dynamics (MD) and molecular mechanics (MM) methods have been used to investigate additive-polymer interfacial properties in single walled carbon nanotube (SWNT)-polyethylene and SWNT-polyacrylonitrile composites. Properties such as the interfacial shear stress and bonding energy are similar for the two composites. In contrast, functionalizing the SWNT with carboxylic acid groups leads to an increase in these properties, with a larger increase for the polar polyacrylonitrile composite. Increasing the percentage of carbon atoms that were functionalized from 1 to 5% also leads to an increase in the interfacial properties. In addition, the interfacial properties depend on the location of the functional groups on the SWNT wall.

  20. 1,2-Dihydroxy-2-(3-methylbut-2-enyl-3-oxo-2,3-dihydro-1H-indene-1-carboxylic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Acácio Ivo Franscisco

    2010-02-01

    Full Text Available The title compound, C15H16O5·H2O, is an intermediate of the Hooker oxidation reaction, used for the synthesis of 2-hydroxy-3-(2-methylprop-1-enylnaphthalene-1,4-dione (nor-lapachol. The packing in the crystal structure is arranged by an O—H...O hydrogen-bonded network along the [100] and [010] directions. Each organic molecule is linked to four other molecules via the hydroxy groups. The water solvent molecule is connected to carboxylic acid groups by three hydrogen bonds.

  1. Studies of lanthanide(III) metal complexes of 7-(D-Α-amino-phenyl-acetamido)-3-methyl-3-cepham-4-carboxylic acid

    International Nuclear Information System (INIS)

    Pingalkar, S.R.; Deshpande, M.N.

    2002-01-01

    Eight new solid complexes of lanthanide(III) chlorides with 7-(DΑ aminophenyl-acetamido)-3-methyl-3-cepham-4-carboxylic acid have been synthesised. These complexes are characterised by elemental analysis, UV and IR spectra, magnetic moment and conductivity data. Inhibitory effect of these complexes and study of antibacterial activity is also undertaken. The IR spectral studies indicate that the ligand acts as tetradentate and it coordinates through nitrogen and oxygen. The general formula of the complexes is [LnL 2 (H 2 O) 2 ]Cl, where Ln = La(III), Ce(III), Pr(III) , Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III). L is 7-(D-Α-aminophenyl- acetamido)-3-methyl-3-cepham-4-carboxylic acid. Coordination number of central metal ion is 10. Inhibitory study of complexes on the corrosion of steel alloy in solution of nitric acid has been done. The inhibitor concentrations of 0.5 to 2% in 0.5 N HNO 3 were used and it was found that inhibitory efficiency increases in the order metal chloride < ligand < complex. Antibacterial activity of AAMCC ligand increases on complexation with lanthanides. (author)

  2. Aziridine Carboxylates, Carboxamides and Lactones: New Methods for Their Preparation and Their Transformation into α- and β-Amino Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Robert H. Dodd

    2000-03-01

    Full Text Available The preparation of a variety of novel aziridine-γ-lactones (3 from carbohydrates is described. In contrast to aziridine-2-carboxylates, the lactones react regiospecifically at C-2 with soft nucleophiles to provide optically pure substituted β-amino acid precursors. Hard nucleophiles react exclusively at the C-3 position to provide α-amino acid precursors. The utility of this methodology was demonstrated by the preparation of (3S,4S-dihydroxy-L-glutamic acid (DHGA from the appropriate aziridine-γ-lactone. DHGA was subsequently shown to be a selective partial agonist of mGluR1 receptors. A more concise preparation of aziridine-γ-lactones was achieved by 1,4-Michael addition of benzylamine to 2-O-triflylbutenolides. Use of a 2-O-mesylbutenolide led, under the same conditions, to the corresponding aziridine-2-carboxamides or 2-carboxylates. Finally, a new Evanstype aziridinating agent, Ses-iminoiodinane, was developed and shown to react efficiently with unsaturated substrates to give the corresponding aziridines, whose N-Ses protecting groups can be removed under mild conditions.

  3. Nafion-assisted cross-linking of sulfonated poly(arylene ether ketone) bearing carboxylic acid groups and their composite membranes for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Haidan; Zhao, Chengji; Na, Hui [Alan G. MacDiarmid Institute, College of Chemistry, Jilin University, Qianjin street 2699, Changchun 130012, Jilin (China)

    2010-06-01

    In this study, a new type of cross-linked composite membrane is prepared and considered for its potential applications in direct methanol fuel cell. Nafion and sulfonated poly(arylene ether ketone) bearing carboxylic acid groups (SPAEK-C) are blended and subsequently cross-linked by a Friedel-Craft reaction using the carboxylic acid groups in the SPAEK-C to achieve lower methanol permeability. The perfluoroalkyl sulfonic acid groups of Nafion act as a benign solid catalyst, which assist the cross-linking of SPAEK-C. The physical and chemical characterizations of the cross-linked composite membranes are performed by varying the contents of SPAEK-C. The c-Nafion-15% membrane exhibits appropriate water uptake (10.49-25.22%), low methanol permeability (2.57 x 10{sup -7} cm{sup 2} s{sup -1}), and high proton conductivity (0.179 S cm{sup -1} at 80 C). DSC and FTIR analyze suggest the cross-linking reaction. These results show that the self-cross-linking of SPAEK-C in the Nafion membrane can effectively reduce methanol permeability while maintaining high proton conductivity. (author)

  4. Electrochemiluminescence and chemiluminescence of a carboxylic acid derivative of ruthenium(II) tris-(2,2'-bipyridine) chelate synthesized for labeling purposes

    International Nuclear Information System (INIS)

    Jiang Qinghong; Sun Shiguo; Hakansson, Markus; Langel, Kaarina; Ylinen, Tiina; Suomi, Johanna; Kulmala, Sakari

    2006-01-01

    Synthesis, purification and characterization of [4-ethoxycarbonyl-4'-carboxy-2,2'-bipyridine]bis(2,2'-bipyridine) ruthenium(II) hexafluorophosphate is described. This complex is shown to be electrochemiluminescent in aqueous solution during cathodic pulse polarization of thin insulating film-coated electrodes. Electrochemiluminescence (ECL) lifetime of the complex was observed to be ca. 40 μs at oxide-coated n-silicon electrodes; thus time-resolved detection is also possible. The ECL emission maximum of this carboxylate derivative is somewhat red-shifted when compared with an unmodified Ru(bpy) 3 2+ . Because the present complex can be easily covalently coupled with antibodies and oligonucleotides it is usable as an electrochemiluminescent label in various bioaffinity assays. The present chelates also produce strong chemiluminescence during dissolution of metallic magnesium in aqueous solution

  5. efficient and convenient synthesis of symmetrical carboxylic

    African Journals Online (AJOL)

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    strong acidity and high activity in light alkane conversions at relatively mild temperatures [36,. 37]. In this paper, we wish to report an efficient and convenient method for the preparation of symmetrical carboxylic anhydrides from the corresponding carboxylic acids with sulfated zirconia by phase transfer catalysis without any ...

  6. Multi-technique Characterization of Self-assembled Carboxylic Acid Terminated Alkanethiol Monolayers on Nanoparticle and Flat Gold Surfaces.

    Science.gov (United States)

    Techane, Sirnegeda D; Gamble, Lara J; Castner, David G

    2011-04-21

    Gold nanoparticles (AuNPs) with 14, 25 and 40nm diameters were functionalized with different chain length (C6, C8, C11 and C16) carboxylic acid terminated alkanethiol self-assembled monolayers (COOH-SAMs). X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to examine the changes in surface chemistry as both AuNP diameter and SAM chain length were varied. COOH-SAMs on flat gold surfaces were also examined and compared to the COOH-SAM on AuNP results. For a given surface, as the COOH-SAM chain length increased the XPS C/Au atomic ratio increased due to an increased number of carbon atoms per molecule in the overlayer and an increased attenuation of the Au substrate signal. For the C16 COOH-SAMs, as the size of AuNPs decreased the XPS C/Au atomic ratio and the apparent SAM thickness increased due to the increased curvature of the smaller AuNPs. The C16 COOH-SAMs on the flat Au had the lowest XPS C/Au atomic ratio and apparent SAM thickness of any C16 COOH-SAM covered Au surface. The effective take-off angles of the COOH-SAMs were also calculated by comparing the apparent thickness of COOH-SAMs with literature values. The effective take-off angle for C16 COOH-SAM on 14nm, 25nm and 40nm diameter AuNPs and flat Au were found to be 57°, 53°, 51° and 39°, respectively, for data acquired in a mode that collects a wide range of photoelectron take-off angles. The effective take-off angle for C16 COOH-SAM on 14nm AuNP and flat Au decreased to 52° and 0°, respectively, for data acquired in a mode that collects a narrow range of photoelectron take-off angles. The ToF-SIMS results showed similar changes in surface chemistry with COOH-SAM chain length and AuNP size. For example, the ratio of the sum of the C(1-4)H(x)O(y) positive ion intensities to the sum of the Au-containing positive ions intensities increased with decreasing AuNP size and increasing COOH-SAM chain length. Fourier transform IR spectroscopy in the

  7. Surface proton transport of fully protonated poly(aspartic acid) thin films on quartz substrates

    International Nuclear Information System (INIS)

    Nagao, Yuki; Kubo, Takahiro

    2014-01-01

    Graphical abstract: - Highlights: • Proton transport of fully protonated poly(aspartic acid) thin film was investigated. • The thin film structure differed greatly from the partially protonated one. • Proton transport occurs on the surface, not inside of the thin film. • This result contributes to biological transport systems such as bacteriorhodopsin. - Abstract: Thin film structure and the proton transport property of fully protonated poly(aspartic acid) (P-Asp100) have been investigated. An earlier study assessed partially protonated poly(aspartic acid), highly oriented thin film structure and enhancement of the internal proton transport. In this study of P-Asp100, IR p-polarized multiple-angle incidence resolution (P-MAIR) spectra were measured to investigate the thin film structure. The obtained thin films, with thicknesses of 120–670 nm, had no oriented structure. Relative humidity dependence of the resistance, proton conductivity, and normalized resistance were examined to ascertain the proton transport property of P-Asp100 thin films. The obtained data showed that the proton transport of P-Asp100 thin films might occur on the surface, not inside of the thin film. This phenomenon might be related with the proton transport of the biological system

  8. Mechanism of in situ surface polymerization of gallic acid in an environmental-inspired preparation of carboxylated core-shell magnetite nanoparticles.

    Science.gov (United States)

    Tóth, Ildikó Y; Szekeres, Márta; Turcu, Rodica; Sáringer, Szilárd; Illés, Erzsébet; Nesztor, Dániel; Tombácz, Etelka

    2014-12-30

    Magnetite nanoparticles (MNPs) with biocompatible coatings are good candidates for MRI (magnetic resonance imaging) contrasting, magnetic hyperthermia treatments, and drug delivery systems. The spontaneous surface induced polymerization of dissolved organic matter on environmental mineral particles inspired us to prepare carboxylated core-shell MNPs by using a ubiquitous polyphenolic precursor. Through the adsorption and in situ surface polymerization of gallic acid (GA), a polygallate (PGA) coating is formed on the nanoparticles (PGA@MNP) with possible antioxidant capacity. The present work explores the mechanism of polymerization with the help of potentiometric acid-base titration, dynamic light scattering (for particle size and zeta potential determination), UV-vis (UV-visible light spectroscopy), FTIR-ATR (Fourier-transformed infrared spectroscopy by attenuated total reflection), and XPS (X-ray photoelectron spectroscopy) techniques. We observed the formation of ester and ether linkages between gallate monomers both in solution and in the adsorbed state. Higher polymers were formed in the course of several weeks both on the surface of nanoparticles and in the dispersion medium. The ratio of the absorbances of PGA supernatants at 400 and 600 nm (i.e., the E4/E6 ratio commonly used to characterize the degree of polymerization of humic materials) was determined to be 4.3, similar to that of humic acids. Combined XPS, dynamic light scattering, and FTIR-ATR results revealed that, prior to polymerization, the GA monomers became oxidized to poly(carboxylic acid)s due to ring opening while Fe(3+) ions reduced to Fe(2+). Our published results on the colloidal and chemical stability of PGA@MNPs are referenced thoroughly in the present work. Detailed studies on biocompatibility, antioxidant property, and biomedical applicability of the particles will be published.

  9. Solvent-induced synthesis of cobalt(II) coordination polymers based on a rigid ligand and flexible carboxylic acid ligands: syntheses, structures and magnetic properties.

    Science.gov (United States)

    Wang, Ting; Zhang, Chuanlei; Ju, Zemin; Zheng, Hegen

    2015-04-21

    Five new cobalt(ii) coordination architectures, {[Co(L)2(H2O)2]·2H2O·2NO3}n (), {[Co(L)(ppda)]·2H2O}n (), {[Co2(L)(ppda)2]2·H2O}n (), {[Co(L)(nba)]·5H2O}n (), and {[Co(L)(oba)]2·3H2O}n (), have been constructed from the rigid ligand L [L = 2,8-di(1H-imidazol-1-yl)dibenzofuran] and different flexible carboxylic acid ligands [H2ppda = 4,4'-(perfluoropropane-2,2-diyl)dibenzoic acid, H2nba = 4,4'-azanediyldibenzoic acid, and H2oba = 4,4'-oxydibenzoic acid]. Depending on the nature of the solvent systems, these five different coordination polymers were synthesized and characterized by single-crystal X-ray diffraction, IR, PXRD and elemental analysis. Compounds , and were obtained by a one-pot method, and then we utilized the solvent-induced effect to obtain almost pure crystals of , respectively. Compound is an infinite 1D chain which is formed by L ligands and Co atoms. Compound contains a [Co2(CO2)4] secondary building unit (SBU), and can be topologically represented as a 6-connected 2-fold interpenetrating pcu net with the point symbol of {4(12)·6(3)}. Compound can be characterized as a 4-connected sql tetragonal planar network with the point symbol of {4(4)·6(2)}. In compounds and , there is a 1D chain which is formed by flexible carboxylic acid ligands and Co atoms; then the 1D chain is linked by L ligands in the tilting direction, leading to the formation of a 2D layer. Furthermore, UV-vis, TGA and magnetic properties have been investigated in detail.

  10. 1-(2-aminophenyl)-1H-1,2,3-triazole-4-carboxylic acid: activity against Gram-positive and Gram-negative pathogens including Vibrio cholerae

    Science.gov (United States)

    Maji, Krishnendu; Haldar, Debasish

    2017-10-01

    We report a new synthetic aromatic ε-amino acid containing a triazole moiety with antimicrobial potential against Gram-positive, Gram-negative and pathogenic bacteria including Vibrio cholerae. Structure-property relationship studies revealed that all the functional groups are essential to enhance the antimicrobial activity. The 1-(2-aminophenyl)-1H-1,2,3-triazole-4-carboxylic acid was synthesized by click chemistry. From X-ray crystallography, the amino acid adopts a kink-like structure where the phenyl and triazole rings are perpendicular to each other and the amine and acid groups maintain an angle of 60°. The agar diffusion test shows that the amino acid has significant antibacterial activity. The liquid culture test exhibits that the minimum inhibitory concentration (MIC) value for Bacillus subtilis and Vibrio cholerae is 59.5 µg ml-1. FE-SEM experiments were performed to study the morphological changes of bacterial shape after treatment with compound 1. The antimicrobial activity of the amino acid was further studied by DNA binding and degradation study, protein binding, dye-binding assay and morphological analysis. Moreover, the amino acid does not have any harmful effect on eukaryotes.

  11. Identification of phenazine-1-carboxylic acid gene (phc CD) from Bacillus pumilus MTCC7615 and its role in antagonism against Rhizoctonia solani.

    Science.gov (United States)

    Padaria, Jasdeep Chatrath; Tarafdar, Avijit; Raipuria, Rajkumar; Lone, Showkat Ahmad; Gahlot, Pallavi; Shakil, Najam A; Kumar, Jitendra

    2016-09-01

    Bacillus pumilus MTCC7615, a biocontrol agent isolated from rice rhizosphere was characterized to be antagonistic to Rhizoctonia solani, the pathogen causing sheath blight disease of rice. The phenazine-1-carboxylic acid gene (phc CD) of this bacterium was PCR amplified (1400 bp), cloned, and sequenced. The sequence analysis revealed the presence of two ORFs of phc CD gene commonly found in Pseudomonas species. The sequence showed 98% similarity to phc CD gene of the Pseudomonas isolate LBUM223 (DQ788993). The crude antibiotic extract from B. pumilus MTCC7615 was observed to inhibit mycelial growth of R. solani under in vitro conditions. The HPLC analysis of crude antibiotic extract from B. pumilus MTCC7615 confirmed the presence of phenazine. The study has also reported the presence of phc CD gene which is responsible for the synthesis of phenazine-1-carboxylic acid in B. pumilus. The ability of the bacterial isolate to control sheath blight disease in rice seedlings under in vivo conditions was confirmed by the pot culture experiment. The structural and functional genomics of phc C and phc D genes would lead to a better understanding of phenazine biosynthesis in B. pumilus for its efficient utilization in plant protection strategies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Simultaneous determination of carbohydrates, carboxylic acids, alcohols, and metals in foods by high-performance liquid chromatography inductively coupled plasma atomic emission spectrometry.

    Science.gov (United States)

    Paredes, Eduardo; Maestre, Salvador E; Prats, Soledad; Todolí, José L

    2006-10-01

    The applicability of the HPLC-ICP-AES coupling for the simultaneous determination of carbohydrates, carboxylic acids, alcohols, and metals in a single chromatographic run has been demonstrated in the present work. Five saccharides, glucose, fructose, sucrose, sorbitol, and lactose; five carboxylic acids, citric, tartaric, malic, lactic, and acetic; and three alcohols, glycerol, ethanol, and methanol, have been determined. A H+ cation exchange column has been used to separate these compounds. The chromatograms have been obtained by monitoring the carbon emission signal at 193.09 nm. The results obtained by HPLC-ICP-AES have been compared against those found with conventional detection systems (i.e., refractive index, UV, and photodyode array detectors). The HPLC-ICP-AES method has shown the following features: (i) organic compounds and metals can be simultaneously determined; (ii) the detection method is universal; (iii) for nonvolatile organic compounds, a complete calibration line can be obtained from a single injection; and (iv) it provides absolute limits of detection similar to or lower than those found with conventional detection systems (i.e., on the order of several tens of nanograms of organic compound). The methodology has been validated through the analysis of food samples such as juices, isotonic beverages, wines, and a certified nonfat milk powder sample.

  13. A Structure-Activity Relationship Study of Imidazole-5-Carboxylic Acid Derivatives as Angiotensin II Receptor Antagonists Combining 2D and 3D QSAR Methods.

    Science.gov (United States)

    Sharma, Mukesh C

    2016-03-01

    Two-dimensional (2D) and three-dimensional (3D) quantitative structure-activity relationship (QSAR) studies were performed for correlating the chemical composition of imidazole-5-carboxylic acid analogs and their angiotensin II [Formula: see text] receptor antagonist activity using partial least squares and k-nearest neighbor, respectively. For comparing the three different feature selection methods of 2D-QSAR, k-nearest neighbor models were used in conjunction with simulated annealing (SA), genetic algorithm and stepwise coupled with partial least square (PLS) showed variation in biological activity. The statistically significant best 2D-QSAR model having good predictive ability with statistical values of [Formula: see text] and [Formula: see text] was developed by SA-partial least square with the descriptors like [Formula: see text]count, 5Chain count, SdsCHE-index, and H-acceptor count, showing that increase in the values of these descriptors is beneficial to the activity. The 3D-QSAR studies were performed using the SA-PLS. A leave-one-out cross-validated correlation coefficient [Formula: see text] and predicate activity [Formula: see text] = 0.7226 were obtained. The information rendered by QSAR models may lead to a better understanding of structural requirements of substituted imidazole-5-carboxylic acid derivatives and also aid in designing novel potent antihypertensive molecules.

  14. RNA interference of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO1 and ACO2) genes expression prolongs the shelf life of Eksotika (Carica papaya L.) papaya fruit.

    Science.gov (United States)

    Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom; Yeong, Wee Chien; Pillai, Vilasini

    2014-06-19

    The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6). Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

  15. Crystal structure of 3-(3,4,5-trimethoxyphenyl-1,2,3,4-tetrahydrocyclopenta[b]indole-2-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Daniara Fernandes

    2015-06-01

    Full Text Available In the title compound, C21H21NO5, obtained from a Morita–Baylis–Hillman adduct, the hydrogenated five-membered ring adopts a shallow envelope conformation, with the C atom bearing the carboxylic acid substituent deviating by 0.237 (1 Å from the mean plane of the other four atoms (r.m.s. deviation = 0.007 Å. The dihedral angle between the fused ring system (all atoms; r.m.s. deviation = 0.057 Å and the pendant trimethoxy benzene ring is 66.65 (3°. The C atoms of the meta-methoxy groups lie close to the plane of the benzene ring [deviations = 0.052 (1 and −0.083 (1 Å], whereas the C atom of the para-methoxy group is significantly displaced [deviation = −1.289 (1 Å]. In the crystal, carboxylic acid inversion dimers generate R22(8 loops. The dimers are connected by N—H...O hydrogen bonds, forming [011] chains. A C—H...O interaction is also observed.

  16. Simultaneous determination of Δ9-tetrahydrocannabinol, cannabidiol, cannabinol and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in hair using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dulaurent, S; Gaulier, J M; Imbert, L; Morla, A; Lachâtre, G

    2014-03-01

    For several years, hair analyses have become a powerful tool to investigate past exposure towards xenobiotics. In the case of illicit drugs and more precisely of cannabis exposure, four compounds are usually investigated: Δ(9)-tetrahydrocannabinol (THC), the main active compound of cannabis, one of its metabolites [11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH)] and two cannabinoids (cannabinol and cannabidiol). Up until now, the hair determination of the carboxylic metabolite of THC, which has been described as the only marker allowing distinguishing consumption and passive exposure, has been performed using a gas chromatography-tandem mass spectrometry method. The aim of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitative determination of the four markers. The sample preparation was based on an alkaline hydrolysis of hair samples followed by a liquid-liquid extraction of compounds in acidic conditions using a hexane/ethyl acetate mixture. The method was validated and the results were satisfactory: intra- and inter-assay accuracies below 9% and relative standard deviation below 15% for the four compounds. Moreover, the limit of quantification for THC-COOH, the most challenging compound, was validated at 0.2 pg/mg. This concentration is in accordance with the recommendations made by a scientific society which specializes in hair testing. It makes it possible to distinguish the kind of exposure to cannabis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. RNA Interference of 1-Aminocyclopropane-1-carboxylic Acid Oxidase (ACO1 and ACO2 Genes Expression Prolongs the Shelf Life of Eksotika (Carica papaya L. Papaya Fruit

    Directory of Open Access Journals (Sweden)

    Rogayah Sekeli

    2014-06-01

    Full Text Available The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6. Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

  18. A copper(II) paddle-wheel structure of tranexamic acid: di-chloro-tetra-kis-[μ-4-(ammonio-meth-yl)cyclo-hexane-1-carboxyl-ato-O,O']dicopper(II) dichloride hexa-hydrate.

    Science.gov (United States)

    Altaf, Muhammad; Stoeckli-Evans, Helen

    2017-10-01

    Tranexamic acid [systematic name: trans -4-(amino-meth-yl)cyclo-hexane-1-carb-oxy-lic acid], is an anti-fibrinolytic amino acid that exists as a zwitterion [ trans -4-(ammonio-meth-yl)cyclo-hexane-1-carboxyl-ate] in the solid state. Its reaction with copper chloride leads to the formation of a compound with a copper(II) paddle-wheel structure that crystallizes as a hexa-hydrate, [Cu 2 Cl 2 (C 8 H 15 NO 2 ) 4 ] 2+ ·2Cl - ·6H 2 O. The asymmetric unit is composed of a copper(II) cation, two zwitterionic tranexamic acid units, a coordinating Cl - anion and a free Cl - anion, together with three water mol-ecules of crystallization. The whole structure is generated by inversion symmetry, with the Cu⋯Cu axle of the paddle-wheel dication being located about a center of symmetry. The cyclo-hexane rings of the zwitterionic tranexamic acid units have chair conformations. The carboxyl-ate groups that bridge the two copper(II) cations are inclined to one another by 88.4 (8)°. The copper(II) cation is ligated by four carboxyl-ate O atoms in the equatorial plane and by a Cl - ion in the axial position. Hence, it has a fivefold O 4 Cl coordination sphere with a perfect square-pyramidal geometry and a τ 5 index of zero. In the crystal, the paddle-wheel dications are linked by a series of N-H⋯Cl hydrogen bonds, involving the coordinating and free Cl - ions, forming a three-dimensional network. This network is strengthened by a series of N-H⋯O water , O water -H⋯Cl and O water -H⋯O hydrogen bonds.

  19. The carboxylic acid transporters Jen1 and Jen2 affect the architecture and fluconazole susceptibility of Candida albicans biofilm in the presence of lactate.

    Science.gov (United States)

    Alves, Rosana; Mota, Sandra; Silva, Sónia; F Rodrigues, Célia; P Brown, Alistair J; Henriques, Mariana; Casal, Margarida; Paiva, Sandra

    2017-11-01

    Candida albicans has the ability to adapt to different host niches, often glucose-limited but rich in alternative carbon sources. In these glucose-poor microenvironments, this pathogen expresses JEN1 and JEN2 genes, encoding carboxylate transporters, which are important in the early stages of infection. This work investigated how host microenvironments, in particular acidic containing lactic acid, affect C. albicans biofilm formation and antifungal drug resistance. Multiple components of the extracellular matrix were also analysed, including their impact on antifungal drug resistance, and the involvement of both Jen1 and Jen2 in this process. The results show that growth on lactate affects biofilm formation, morphology and susceptibility to fluconazole and that both Jen1 and Jen2 might play a role in these processes. These results support the view that the adaptation of Candida cells to the carbon source present in the host niches affects their pathogenicity.

  20. Synthesis, characterization and metal coordination of a potential β-lactamase inhibitor: 5-Methyl-2-phenoxymethyl-3-H-imidazole-4-carboxylic acid (PIMA

    Directory of Open Access Journals (Sweden)

    Chiara Romagnoli

    2017-12-01

    Full Text Available Among relevant metal ions in biological systems, zinc and iron play a key role as active partners of the catalytic machinery. In particular, the inhibition of metal enzymes that are involved in physiological and pathological processes has been deeply investigated for the rational design of selective and efficient drugs based on chelators. Since imidazole histidine residue is one of the most versatile sites in proteins, especially in enzymes acting in the presence of metal ions as cofactors, in this work the synthesis and characterization of a new imidazole derivative, namely 5-methyl-2-phenoxymethyl-3-H-imidazole-4-carboxylic acid (PIMA is reported. PIMA was designed as metallo-β-lactamase inhibitor thanks to its similarity with penicillin V, a β-lactam antibiotic inactivated by metallo-β-lactamase, for which there are no commercially available inhibitors. The evaluation of PIMA coordinating ability toward iron, zinc, and gallium, these latter selected as a non-paramagnetic probe for iron, is performed by theoretical DFT calculations and in solution by experimental techniques, i.e. potentiometry, UV–vis and NMR spectroscopy. PIMA exhibits an efficient metal chelating ability; the prevailing species in physiological condition are ML3 for Fe3+ and Ga3+ and ML2 for Zn2+, in which chelation is due to deprotonated carboxylic oxygen and imidazole nitrogen in the N,O donor set. The demonstrated ability of PIMA to chelate zinc ion, combined with its structure similarity with penicillin V, supports further exploration of this imidazole-4-carboxylate as metallo-β-lactamase inhibitor.

  1. THE EFFECT OF KETAMINE AND ITS COMBINATION WITH INDOL-2-CARBOXYLIC ACID AND CAROVERINE ON SURVIVAL TIME OF MICE WITH EXPERIMENTAL TETANUS

    Directory of Open Access Journals (Sweden)

    Indira Mujezinović

    2017-12-01

    Full Text Available Tetanus, also known as lockjaw, is a very dangerous infectious acute, usually afebrile disease characterized by muscle spasms, affecting humans and various animal species. The causative agent of the disease is bacteria Clostridium tetani. This bacteria produces a specific neurotoxin known as Tetanus toxin, which consists of two components: tetanospasmin and tetanolysin. Light (L chains of tetanospamin cleavage synaptobrevin, an integral membrane component of the synaptic vesicles, which in turn prevent release of the inhibitory neurotransmitter γ-aminobutyric acid (GABA into the synaptic cleft. The α- motor neurons are, therefore, under no inhibitory control as a result of which they undergo sustained excitatory discharge causing the characteristic motor spasms of tetanus. In this research, we attempted to normalize the disorders caused by tetanus toxin by using ketamine, a non-competitive antagonist of aspartate (at doses of 5, 10, 44 and 100 mg/kg of body weight – b.w., alone and in combination with indol-2-carboxylic acid, a competitive antagonist of aspartate (at a dose of 10 mg/kg b.w. and caroverine, a non-competitive antagonist of glutamate (at a dose of 1.2 mg/kg b.w.. Experiments were conducted on the albino mice of both sexes, weighing around 20-25 g. Experimental tetanus was induced by application of tetanus toxin. The administration of ketamine, alone and in combination with indol-2-carboxylic acid and caroverine was carried out 24 hours after administration of tetanus toxin once per day, until the mice died. It was found that ketamine had an effect only at a dose of 10 mg/kg b.w., which slightly prolonged the LD50 periodin experimental group of mice, compared to the control group of mice with experimental tetanus. Thus, it can be concluded that administration of ketamine in this dose proved to be only slightly effective. On the other hand, combination of ketamine with indol-2-carboxylic acid slightly extended the survival time

  2. The phytotoxicity to tobacco plants of short-chain carboxylic acids at atmospheric concentration levels in urban areas.

    Science.gov (United States)

    Hirabayashi, M; Ozaki, T; Matsuo, M

    2001-03-01

    In this paper, we describe the influence of monocarboxylic acids (formic acid and acetic acid) and dicarboxylic acids (succinic acid and adipic acid), which are usually contained in aerosol particles and fog water, on the growth of tobacco plant. Their influence was examined by spraying the acid solutions on intact plants and by administering them in a culture medium for suspension-cultured cells. Their growth rates suggest that the influence of short-chain monocarboxylic acids was not significant in both the intact plant experiment and the cell culture experiment. In contrast, dicarboxylic acids exhibited significant influence on the growth of intact plants and no influence on culture cells, indicating that their toxicity is exerted mainly on the tissue of leaf surface. Phytotoxicity of dicarboxylic acids is higher than that of monocarboxylic acids.

  3. Determining aromatic and aliphatic carboxylic acids in biomass-derived oil samples using 2,4-dinitrophenylhydrazine and liquid chromatography-electrospray injection-mass spectrometry/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Samuel A.; Connatser, Raynella M.; Olarte, Mariefel V.; Keiser, James R.

    2018-01-01

    Converting biomass to a useful fuel commonly incorporates the pyrolysis of the biomass feed stock. The base liquid fraction usually contains high concentrations of ketones, aldehydes and carboxylic acids, of which each can cause detrimental issues related to the storage and upgrading process. Knowing the carbonyl species and the concentration of each will provide value information to the pyrolysis researchers, specifically as that community branches into more targeted end-products such as jet fuel or biogenic-derived oxygenate-containing fuel products. The analysis of aldehydes, ketones and small alkyl carboxylic acids using 2,4-dinitrophenylhydrazine (DNPH) derivation method has been well documented and the method is commonly used the analytical community. By using liquid chromatograph coupled to tandem mass spectrometry, biomass sample analysis can be complete with identification of most carbonyl species. The issue of identifying isobaric ketone and aldehyde compounds can be resolved by utilizing differences in retention time or characteristic fragment ions of ketones and aldehydes. One issue which could not resolved using published methods was identifying aromatic or large non-aromatic carboxylic acids from their corresponding hydroxyl aldehyde or ketone analogs. By modifying the current method for determining carbonyls in biomass samples, carboxylic and hydroxyl-carbonyl can be determined. A careful adjustment of the pH during the extraction procedure and extended heating time of the DNPH solution allowed for the successful derivation of aromatic carboxylic acids. Like other dinitrophenylhydrazones, carboxylic acid derivatives also produce a unique secondary ion pattern, which was useful to distinguish these species from the non-acid analogs.

  4. Determination of carboxyl groups in wood fibers by headspace gas chromatography

    Science.gov (United States)

    X.-S. Chai; Q.X. Hou; J.Y. Zhu; S.-L. Chen; S.F. Wang; L. Lucia

    2003-01-01

    The phase reaction conversion (PRC) headspace gas chromatographic (HSGC) technique was employed to develop a method for the determination of the content of carboxyl groups in wood fibers. Acid treatment of the wood fibers using hydrochloric was applied to convert carboxyl groups to carboxyl acids. Bicarbonate solution is then used to react with carboxyl acids on the...

  5. Nine supramolecular assemblies from 5,7-dimethyl-1,8-naphthyridine-2-amine and carboxylic acids by strong classical H-bonds and other noncovalent associations

    Science.gov (United States)

    Ding, Aihua; Jin, Shouwen; Jin, Shide; Guo, Ming; Liu, Hui; Guo, Jianzhong; Wang, Daqi

    2017-12-01

    This article demonstrates 5,7-dimethyl-1,8-naphthyridine-2-amine based organic salt formation in nine crystalline solids 1-9, in which the carboxylates have been integrated. Addition of equivalents of the COOH to the solution of 5,7-dimethyl-1,8-naphthyridine-2-amine generates the singly protonated cationic species which direct the carboxylates. The nine compounds crystallize as their organic salts with the COOH proton transferred to the aromatic N of the 5,7-dimethyl-1,8-naphthyridine-2-amine. All salts have been characterized by IR, mp, EA and XRD technique. The major driving force in 1-9 is the classical H-bonds from 5,7-dimethyl-1,8-naphthyridine-2-amine and the acids, here the Nsbnd H⋯O H-bonds were found in all salts. Other extensive non-covalent interactions also exhibit great functions in space association of the molecular counterparts in relevant crystals. Except 4, all salts had the CHsbnd O, or CH3sbnd O interactions or both. Except 9, the common R22 (8) graph set has been observed in all salts due to the H-bonds and the non-covalent associations. For the synergistic interactions of the classical H-bonds and the various non-covalent associations, the salts displayed 1D-3D structures.

  6. 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt): unsuccessful search for a marker of combined cannabis and alcohol consumption.

    Science.gov (United States)

    Nadulski, Thomas; Bleeck, Simona; Schräder, Johannes; Bork, Wolf-Rainer; Pragst, Fritz

    2010-03-20

    11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt) can be presumed to be a mixed metabolite formed during combined consumption of cannabinoids and alcohol. In order to examine this hypothesis, THC-COOEt and its deuterated analogue D(3)-THC-COOEt were synthesized as reference substance and internal standard from the corresponding carboxylic acids and diazoethane and methods were developed for the sensitive detection of THC-COOEt in plasma and hair based on gas chromatography-electron impact mass spectrometry after silylation with N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS) as well as tandem mass spectrometry (GC-NCI-MS-MS) after derivatization with pentafluoropropionyl anhydride. The methods were applied for THC-COOEt determination to plasma samples from 22 drunk driving cases which contained both ethanol (0.30-2.16 mg/g) and THC-COOH (15-252 ng/mL) as well as to 12 hair samples from drug fatalities which were both positive for THC (0.09-2.04 ng/mg) and fatty acid ethyl esters as markers of chronic alcohol abuse (0.70-6.3 ng/mg). In none of these samples THC-COOEt could be found with limits of detection of 0.3 ng/mL in plasma and 2 pg/mg in hair in 11 samples using GC-NCI-MS and 0.2 pg/mg in one sample using GC-NCI-MS. Therefore, the use of this compound as a marker for combined cannabis and alcohol consumption could not be achieved. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  7. Systematic evaluation and optimization of modification reactions of oligonucleotides with amines and carboxylic acids for the synthesis of DNA-encoded chemical libraries.

    Science.gov (United States)

    Franzini, Raphael M; Samain, Florent; Abd Elrahman, Maaly; Mikutis, Gediminas; Nauer, Angela; Zimmermann, Mauro; Scheuermann, Jörg; Hall, Jonathan; Neri, Dario

    2014-08-20

    DNA-encoded chemical libraries are collections of small molecules, attached to DNA fragments serving as identification barcodes, which can be screened against multiple protein targets, thus facilitating the drug discovery process. The preparation of large DNA-encoded chemical libraries crucially depends on the availability of robust synthetic methods, which enable the efficient conjugation to oligonucleotides of structurally diverse building blocks, sharing a common reactive group. Reactions of DNA derivatives with amines and/or carboxylic acids are particularly attractive for the synthesis of encoded libraries, in view of the very large number of building blocks that are commercially available. However, systematic studies on these reactions in the presence of DNA have not been reported so far. We first investigated conditions for the coupling of primary amines to oligonucleotides, using either a nucleophilic attack on chloroacetamide derivatives or a reductive amination on aldehyde-modified DNA. While both methods could be used for the production of secondary amines, the reductive amination approach was generally associated with higher yields and better purity. In a second endeavor, we optimized conditions for the coupling of a diverse set of 501 carboxylic acids to DNA derivatives, carrying primary and secondary amine functions. The coupling efficiency was generally higher for primary amines, compared to secondary amine substituents, but varied considerably depending on the structure of the acids and on the synthetic methods used. Optimal reaction conditions could be found for certain sets of compounds (with conversions >80%), but multiple reaction schemes are needed when assembling large libraries with highly diverse building blocks. The reactions and experimental conditions presented in this article should facilitate the synthesis of future DNA-encoded chemical libraries, while outlining the synthetic challenges that remain to be overcome.

  8. Organosulfates and Carboxylic Acids in Secondary Organic Aerosols in Coniferous Forests in Rocky Mountains (USA), Sierra Nevada Mountains (USA) and Northern Europe (Finland and Denmark)

    Science.gov (United States)

    Glasius, M.; Hansen, A. M. K.; Kristensen, K.; Kristensen, T. B.; Mccubbin, I. B.; Hallar, A. G.; Petäjä, T.; Surratt, J. D.; Worton, D. R.; Bilde, M.; Kulmala, M. T.; Goldstein, A. H.

    2014-12-01

    Levels and chemical composition of secondary organic aerosols affect their climate effects and properties. Organosulfates (OS) are formed through heterogeneous reactions involving oxidized sulfur compounds, primarily originating from anthropogenic sources. Availability of authentic standards have until now been an obstacle to quantitative investigations of OS in atmospheric aerosols. We have developed a new, facile method for synthesis and purification of OS standards. Here we have used 7 standards to quantify OS and nitrooxy organosulfates (NOS) observed in aerosols collected at four sites in coniferous forests in USA and Europe during spring or summer. The two American sites were Storm Peak Laboratory, Colorado (Rocky Mountains, elevation 3220 m a.s.l) and Sierra Nevada Mountains, California (as part of BEARPEX 2007 and 2009). The European sites were Hyytiälä Forest Station, Finland (in the boreal zone) and Silkeborg, Denmark (temperate forest). Aerosol filter samples were extracted and analyzed using a high performance liquid chromatograph coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (HPLC-QTOF-MS). We identified 11 carboxylic acids using authentic standards, while 16 different OS and 8 NOS were identified based on their molecular mass and MS fragmentation patterns, as well as comparison with available standards. OS were ubiquitous in the atmospheric aerosol samples, even at the high elevation mountain station. Levels of carboxylic acids from oxidation of monoterpenes were 8-25 ng m-3 at Silkeborg and Storm Peak Laboratory, while concentrations at the sites with strong regional monoterpene emissions (Sierra Nevada Mountains and Hyytiälä) were much higher (10-200 ng m-3). At all sites, the dominant group of OS were derived from isoprene (IEPOX) and related compounds, while OS of monoterpenes showed lower concentrations, except at Hyytiälä during periods of north-westerly winds when monoterpene OS were at similar or

  9. Zymogen-activation kinetics. Modulatory effects of trans-4-(aminomethyl)cyclohexane-1-carboxylic acid and poly-D-lysine on plasminogen activation.

    Science.gov (United States)

    Petersen, L C; Brender, J; Suenson, E

    1985-01-01

    The kinetics of plasminogen activation catalysed by urokinase and tissue-type plasminogen activator were investigated. Kinetic measurements are performed by means of a specific chromogenic peptide substrate for plasmin, D-valyl-L-leucyl-L-lysine 4-nitroanilide. Two methods are proposed for the analysis of the resulting progress curve of nitroaniline formation in terms of zymogen-activation kinetics: a graphical transformation of the parabolic curve and transformation of the curve for nitroaniline production into a linear progress curve by the addition of a specific inhibitor of plasmin, bovine pancreatic trypsin inhibitor. The two methods give similar results, suggesting that the reaction between activator and plasminogen is a simple second-order reaction at least at plasminogen concentrations up to about 10 microM. The kinetics of both Glu1-plasminogen (residues 1-790) and Lys77-plasminogen (residues 77-790) activation were investigated. The results confirm previous observations showing that trans-4-(aminomethyl)cyclohexane-1-carboxylic acid at relatively low concentrations enhances the activation rate of Glu1-plasminogen but not that of Lys77-plasminogen. At higher concentrations both Glu1- and Lys77-plasminogen activation are inhibited. The concentration interval for the inhibition of urokinase-catalysed reactions is shown to be very different from that of the tissue-plasminogen activator system. Evidence is presented indicating that binding to the active site of urokinase (KD = 2.0 mM) is responsible for the inhibition of the urokinase system, binding to the active site of tissue-plasminogen activator is approx. 100-fold weaker, and inhibition of the tissue-plasminogen activator system, when monitored by plasmin activity, is mainly due to plasmin inhibition. Poly-D-lysine (Mr 160 000) causes a marked enhancement of plasminogen activation catalysed by tissue-plasminogen activator but not by urokinase. Bell-shaped curves of enhancement as a function of the

  10. Immune Modulation in Normal Human Peripheral Blood Mononuclear Cells (PBMCs) (Lymphocytes) in Response to Benzofuran-2-Carboxylic Acid Derivative KMEG during Spaceflight

    Science.gov (United States)

    Okoro, Elvis; Mann, Vivek; Ellis, Ivory; Mansoor, Elvedina; Olamigoke, Loretta; Marriott, Karla Sue; Denkins, Pamela; Williams, Willie; Sundaresan, Alamelu

    2017-08-01

    Microgravity and radiation exposure during space flight have been widely reported to induce the suppression of normal immune system function, and increase the risk of cancer development in humans. These findings pose a serious risk to manned space missions. Interestingly, recent studies have shown that benzofuran-2-carboxylic acid derivatives can inhibit the progression of some of these devastating effects on earth and in modeled microgravity. However, these studies had not assessed the impacts of benzofuran-2- carboxylic acid and its derivatives on global gene expression under spaceflight conditions. In this study, the ability of a specific benzofuran-2-carboxylic acid derivative (KMEG) to confer protection from radiation and restore normal immune function was investigated following exposure to space flight conditions on the ISS. Normal human peripheral blood mononuclear cells (lymphocytes) treated with 10 µ g/ml of KMEG together with untreated control samples were flown on Nanoracks hardware on Spacex-3 flight. The Samples were returned one month later and gene expression was analyzed. A 1g-ground control experiment was performed in parallel at the Kennedy spaceflight center. The first overall subtractive unrestricted analysis revealed 78 genes, which were differentially expressed in space flight KMEG, untreated lymphocytes as compared to the corresponding ground controls. However, in KMEG-treated space flight lymphocytes, there was an increased expression of a group of genes that mediate increased transcription, translation and innate immune system mediating functions of lymphocytes as compared to KMEG-untreated samples. Analysis of genes related to T cell proliferation in spaceflight KMEG-treated lymphocytes compared to 1g-ground KMEG- treated lymphocytes revealed six T cell proliferation and signaling genes to be significantly upregulated (p role in promoting the proliferation of T-lymphocytes, the regulation of membrane trafficking, promote early response

  11. Carboxyl group reactivity in actin

    Energy Technology Data Exchange (ETDEWEB)

    Elzinga, M.

    1986-01-01

    While earlier work showed that the carboxyl groups of proteins could be quantitatively coupled to amino groups at pH 4.75 in the presence of EDC and a denaturing agent, the work presented here indicates that under milder conditions the modification of sidechain carboxyls is limited and somewhat specific. Most of the incorporated glycine ethyl ester (GEE) is apparently bound to five carboxyls. The total GEE incorporated was 3 to 4 moles/mole of protein as measured by an increase in Gly upon acid hydrolysis and amino acid analysis, as well as total radioactivity. 3.55 residues were found in peptides, 2.75 bound to residues 1 to 4, and 0.8 bound to Gly-100. 9 refs., 2 figs., 2 tabs.

  12. Carboxyl group reactivity in actin

    International Nuclear Information System (INIS)

    Elzinga, M.

    1986-01-01

    While earlier work showed that the carboxyl groups of proteins could be quantitatively coupled to amino groups at pH 4.75 in the presence of EDC and a denaturing agent, the work presented here indicates that under milder conditions the modification of sidechain carboxyls is limited and somewhat specific. Most of the incorporated glycine ethyl ester (GEE) is apparently bound to five carboxyls. The total GEE incorporated was 3 to 4 moles/mole of protein as measured by an increase in Gly upon acid hydrolysis and amino acid analysis, as well as total radioactivity. 3.55 residues were found in peptides, 2.75 bound to residues 1 to 4, and 0.8 bound to Gly-100. 9 refs., 2 figs., 2 tabs

  13. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, J.; Kuriyama, K. (Kyoto Prefectural Univ. of Medicine (Japan))

    1990-05-01

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited (3H)flunitrazepam binding to benzodiazepine receptor, but not (3H)muscimol binding to GABAA receptor as well as t-(3H)butylbicycloorthobenzoate (( 3H) TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively (3H) flunitrazepam binding. On the other hand, the binding of beta-(3H)CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated (3H)muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-(3H)CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for (3H)flunitrazepam, (3H)muscimol and (3H)TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested.

  14. Synthesis and structural characterization of derivatives of 2- and 3-benzo[b]furan carboxylic acids with potential cytotoxic activity.

    Science.gov (United States)

    Kossakowski, Jerzy; Ostrowska, Kinga; Hejchman, Elzbieta; Wolska, Irena

    2005-01-01

    Derivatives of 2- and 3-benzo[b]furancarboxylic acids were prepared and evaluated for their cytotoxic potential in the National Cancer Institute, Bethesda, USA. Six compounds: 7-acetyl-6-hydroxy-3-methyl-2-benzofurancarboxylic acid (2), 6-hydroxy-7-(p-methoxycinnamoyl)-3-methyl-2-benzofurancarboxylic acid (4), 5-bromo-7-hydroxy-6-methoxy-2-benzofurancarboxylic acid methyl ester (6a), 6-acetyl-5-(O-ethyl-2'-diethylamino)-2-methyl-3-benzofurancarboxylic acid methyl ester (1f), 6-(O-ethyl-2'-diethylamino)-7-p-methoxycinnamoyl)-3-methyl-2-benzofurancarboxylic acid methyl ester hydrochloride (4b), 5-bromo-7-(O-ethyl-2'-diethylamino)-6-methoxy-2-benzofurancarboxylic acid methyl ester (6b) showed significant cytotoxic activities against human cancer cell lines. In addition the crystal structures of 7-methoxy-2-benzofurancarboxylic acid methyl ester (7a) has been solved by X-ray structure analysis of single crystals.

  15. Expression and regulation of pear 1-aminocyclopropane-1-carboxylic acid synthase gene (PpACS1a) during fruit ripening, under salicylic acid and indole-3-acetic acid treatment, and in diseased fruit.

    Science.gov (United States)

    Shi, Hai-Yan; Zhang, Yu-Xing

    2014-06-01

    In plants, the level of ethylene is determined by the activity of the key enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS). A gene encoding an ACC synthase protein was isolated from pear (Pyrus pyrifolia). This gene designated PpACS1a (GenBank accession no. KC632526) was 1488 bp in length with an open reading frame (ORF) encoding a protein of 495 amino acids that shared high similarity with other pear ACC synthase proteins. The PpACS1a was grouped into type-1 subfamily of plant ACS based on its conserved domain and phylogenetic status. Real-time quantitative PCR indicated that PpACS1a was differentially expressed in pear tissues and predominantly expressed in anthers. The expression signal of PpACS1a was also detected in fruit and leaves, but no signal was detected in shoots and petals. Furthermore, the PpACS1a expression was regulated during fruit ripening. In addition, the PpACS1a gene expression was regulated by salicylic acid (SA) and indole-3-acetic acid (IAA) in fruit. Moreover, the expression of the PpACS1a was up-regulated in diseased pear fruit. These results indicated that PpACS1a might be involved in fruit ripening and response to SA, IAA and disease.

  16. Quantitation of 11 -nor-delta9-tetrahydrocannabinol-9-carboxylic acid with GC-MS in urine collected for doping analysis.

    Science.gov (United States)

    De Cock, K J S; Delbeke, F T; De Boer, D; Van Eenoo, P; Roels, K

    2003-03-01

    An accurate, reproducible, and validated gas chromatography-mass spectrometry (GC-MS) method for the quantitation of 11 -nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), the major metabolite of delta9-tetrahydrocannabinol, in urine is described. Extraction was performed with n-hexane/ethyl acetate. Deuterated THC-COOH was used as the internal standard. The GC-MS analysis was done by selected ion monitoring. No interferences were detected in 20 blank urine samples of different origin. The calibration curve was found to be linear over the range of 10-100 ng/mL. The calculated limits of detection and quantitation were 1.0 ng/mL and 1.7 ng/mL, respectively. Results of positive findings for cannabis use in doping control in Flanders and Portugal in the period of 1997-2000 are commented.

  17. Synthesis, Antifungal Activity and Structure-Activity Relationships of Novel 3-(Difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid Amides

    Directory of Open Access Journals (Sweden)

    Shijie Du

    2015-05-01

    Full Text Available A series of novel 3-(difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid amides were synthesized and their activities were tested against seven phytopathogenic fungi by an in vitro mycelia growth inhibition assay. Most of them displayed moderate to excellent activities. Among them N-(2-(5-bromo-1H-indazol-1-ylphenyl-3-(difluoro-methyl-1-methyl-1H-pyrazole-4-carboxamide (9m exhibited higher antifungal activity against the seven phytopathogenic fungi than boscalid. Topomer CoMFA was employed to develop a three-dimensional quantitative structure-activity relationship model for the compounds. In molecular docking, the carbonyl oxygen atom of 9m could form hydrogen bonds towards the hydroxyl of TYR58 and TRP173 on SDH.

  18. Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl ketones using alpha,omega-diols as alkylating agents.

    Science.gov (United States)

    Iuchi, Yosuke; Hyotanishi, Megumi; Miller, Brittany E; Maeda, Kensaku; Obora, Yasushi; Ishii, Yasutaka

    2010-03-05

    Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl diketones was successfully achieved by using alpha,omega-diols as alkylating agents under the influence of an iridium catalyst. For example, the alkylation of butyl cyanoacetate with 1,13-tridecanediol in the presence of [IrCl(cod)](2) or [IrCl(coe)(2)](2) gave rise to butyl 2-cyano-15-hydroxypentadecanoate in good yield which is easily converted to cyclopentadecanolide (CPDL). In addition, the alkylation of acetone with 1,10-decanediol in the presence of [IrCl(cod)](2) and KOH resulted in an important muscone precursor, 2,15-hexadecanedione (HDDO), in good yield.

  19. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2--The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

    Science.gov (United States)

    Luca, Oana R; Fenwick, Aidan Q

    2015-11-01

    The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Cellulose bearing Schiff base and carboxylic acid chelating groups: a low cost and green adsorbent for heavy metal ion removal from aqueous solution.

    Science.gov (United States)

    Saravanan, R; Ravikumar, L

    2016-10-01

    Chemically modified cellulose bearing metal binding sites like Schiff base and carboxylic acid groups was synthesized and characterized through Fourier transform infrared and solid state 13 C-nuclear magnetic resonance (NMR) analysis. The chemically modified cellulose (Cell-PA) adsorbent was examined for its metal ion uptake ability for Cu(II) and Pb(II) ions from aqueous solution. Kinetic and isotherm studies were carried out under optimum conditions. Pseudo-second-order kinetics and Langmuir isotherm fit well with the experimental data. Thermodynamic studies were also performed along with adsorption regeneration performance studies. The adsorbent (Cell-PA) shows high potential for the removal of Cu(II) and Pb(II) metal ions, and it shows antibacterial activity towards selected microorganisms.

  1. Protective effects of chelating agents of catechols amino carboxylic acid type on radiation injury induced by radiothorium in mice II. delayed administration

    International Nuclear Information System (INIS)

    Chen Honghong; Hu Yuxing; Wang Yinghua; Jin Meiying; Luo Meichu; Sun Meizhen

    2003-01-01

    Objective: To explore antioxidation efficacy of chelating agents (9501, 7601) of catechols amino carboxylic acid type for radiothorium in vivo and relationship between their antioxidation and decorporation effects. To verify whether 9501 and 7601 could improve the protective effects for internal radiation injury. Methods: The chelating agents were administered intramuscularly to ICR mice 3 days after intraperitoneal injection of 0.6 MBq 234 Th-citrate for three consecutive days and the animals were sacrificed eight days later. The 234 Th radioactivity in the whole body and its retention in the liver and skeleton were determined. The malondialdehyde (MDA) production as an index of 234 Th-induced lipid peroxidation in bone marrow and liver was assayed and the numbers of bone marrow nucleated cells (NBMNC) were counted. The pathological changes of bone marrow and liver tissue were observed. Results: When 9501 and 7601 and DTPA were postponed to administer to 234 Th-incorporated mice, the whole body radioactivity was only decreased by 15%-16% and the retention of 234 Th in the liver, and skeleton was reduced to 77%-79% and 72%-75% as compared with the control group, respectively. They showed the similar removal effectiveness which was significantly lower than that when administered promptly. However, 9501 and 7601 could inhibit 234 Th-induced lipid peroxidation, causing significant reduction of MDA content in bone marrow and liver, and markedly ameliorate histopathological changes of bone marrow and liver tissue in 234 Th-treated mice. DTPA appeared to have a lower effectiveness. VitE hadn't decorporation activity and slightly alleviated internal radiation injury. Conclusion: The chelating agents 9501 and 7601 of catechols amino carboxylic acid type have double functions of more effective decorporation and antioxidation and can improve the curative effects. They are worth further investigation

  2. Applications of Poly(indole-6-carboxylic acid-co-2,2′-bithiophene Films in High-Contrast Electrochromic Devices

    Directory of Open Access Journals (Sweden)

    Chung-Wen Kuo

    2018-03-01

    Full Text Available Two homopolymers (poly(indole-6-carboxylic acid (PInc and poly(2,2′-bithiophene (PbT and a copolymer (poly(indole-6-carboxylic acid-co-2,2′-bithiophene (P(Inc-co-bT are electrodeposited on ITO electrode surfaces via electrochemical method. Electrochemical and electrochromic properties of PInc, PbT, and P(Inc-co-bT films were characterized using cyclic voltammetry and in situ UV-Vis spectroscopy. The anodic P(Inc-co-bT film prepared using Inc./bT = 1/1 feed molar ratio shows high optical contrast (30% at 890 nm and coloring efficiency (112 cm2 C−1 at 890 nm. P(Inc-co-bT film revealed light yellow, yellowish green, and bluish grey in the neutral, intermediate, and oxidation states, respectively. Electrochromic devices (ECDs were constructed using PInc, PbT, or P(Inc-co-bT film as anodic layer and PEDOT-PSS as cathodic layer. P(Inc-co-bT/PMMA-PC-ACN-LiClO4/PEDOT-PSS ECD showed high ∆T (31% at 650 nm, and PInc/PMMA-PC-ACN-LiClO4/PEDOT-PSS ECD displayed high coloration efficiency (416.7 cm2 C−1 at 650 nm. The optical memory investigations of PInc/PMMA-PC-ACN-LiClO4/PEDOT-PSS, PbT/PMMA-PC-ACN-LiClO4/PEDOT-PSS, and P(Inc-co-bT/PMMA-PC-ACN-LiClO4/PEDOT-PSS ECDs exhibited that ECDs had adequate optical memory in bleaching and coloring states.

  3. Pre-staining thin layer chromatography method for amino acid ...

    African Journals Online (AJOL)

    Jane

    2010-12-13

    Dec 13, 2010 ... chromatogram of 22 amino acids. The two TLC methods were performed simultaneously under the same conditions. Line1: Alanine, 2: Phenylalanine, 3: Cysteine, 4: Cystine, 5: Aspartic Acid, 6: Asparagine, 7: Glutamic Acid, 8: Glutamine, 9: Glycine, 10: Histidine, 11: Leucine, 12: Isoleucine, 13: Lysine, 14:.

  4. Synthesis and optical characterization of acid-doped polyaniline thin ...

    African Journals Online (AJOL)

    Polyaniline has attracted much interest among researchers because of its reasonably good conductivity, stability, ease of preparation, affordability and redox properties compared to other organic compounds. In this work, Polyaniline (PANI) thin films were synthesized by chemical oxidative polymerization of aniline in the ...

  5. Comparative hepatotoxicity of 6:2 fluorotelomer carboxylic acid and 6:2 fluorotelomer sulfonic acid, two fluorinated alternatives to long-chain perfluoroalkyl acids, on adult male mice.

    Science.gov (United States)

    Sheng, Nan; Zhou, Xiujuan; Zheng, Fei; Pan, Yitao; Guo, Xuejiang; Guo, Yong; Sun, Yan; Dai, Jiayin

    2017-08-01

    Due to their structural similarities, 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and 6:2 fluorotelomer carboxylic acid (6:2 FTCA) are often used as alternatives to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), respectively. With limited health risk data and 6:2 FTSA detection in water and sludge, the toxicity of these chemicals is of growing concern. Here, adult male mice were exposed with 5 mg/kg/day of 6:2 FTCA or 6:2 FTSA for 28 days to investigate their hepatotoxicological effects. In contrast to 6:2 FTCA, 6:2 FTSA was detected at high and very high levels in serum and liver, respectively, demonstrating bioaccumulation potential and slow elimination. Furthermore, 6:2 FTSA induced liver weight increase, inflammation, and necrosis, whereas 6:2 FTCA caused no obvious liver injury, with fewer significantly altered genes detected compared with that of 6:2 FTSA (39 vs. 412). Although PFOA and PFOS commonly activate peroxisome proliferator-activated receptor α (PPARα), 6:2 FTSA induced an increase in PPARγ and related proteins, but not in lipid metabolism-related genes such as PPARα. Our results showed that 6:2 FTCA and 6:2 FTSA exhibited weak and moderate hepatotoxicity, respectively, compared with that reported for legacies PFOA and PFOS.

  6. Metabolism of Citrate and Other Carboxylic Acids in Erythrocytes As a Function of Oxygen Saturation and Refrigerated Storage

    Directory of Open Access Journals (Sweden)

    Travis Nemkov

    2017-10-01

    Full Text Available State-of-the-art proteomics technologies have recently helped to elucidate the unanticipated complexity of red blood cell metabolism. One recent example is citrate metabolism, which is catalyzed by cytosolic isoforms of Krebs cycle enzymes that are present and active in mature erythrocytes and was determined using quantitative metabolic flux analysis. In previous studies, we reported significant increases in glycolytic fluxes in red blood cells exposed to hypoxia in vitro or in vivo, an observation relevant to transfusion medicine owing to the potential benefits associated with hypoxic storage of packed red blood cells. Here, using a combination of steady state and quantitative tracing metabolomics experiments with 13C1,2,3-glucose, 13C6-citrate, 13C515N2-glutamine, and 13C1-aspartate via ultra-high performance liquid chromatography coupled on line with mass spectrometry, we observed that hypoxia in vivo and in vitro promotes consumption of citrate and other carboxylates. These metabolic reactions are theoretically explained by the activity of cytosolic malate dehydrogenase 1 and isocitrate dehydrogenase 1 (abundantly represented in the red blood cell proteome, though moonlighting functions of additional enzymes cannot be ruled out. These observations enhance understanding of red blood cell metabolic responses to hypoxia, which could be relevant to understand systemic physiological and pathological responses to high altitude, ischemia, hemorrhage, sepsis, pulmonary hypertension, or hemoglobinopathies. Results from this study will also inform the design and testing of novel additive solutions that optimize red blood cell storage under oxygen-controlled conditions.

  7. An organocatalytic Michael-cyclization cascade of 4-oxa-α,β-unsaturated carboxylic acids with aldehydes: facile synthesis of chiral γ-lactols and trisubstituted γ-lactones.

    Science.gov (United States)

    Lin, Jun-Bing; Xu, Shi-Ming; Xie, Ji-Kang; Li, Hong-Yu; Xu, Peng-Fei

    2015-02-28

    An organocatalytic Michael-cyclization cascade of aldehydes with 4-oxa-α,β-unsaturated carboxylic acids has been developed, giving functionalized γ-lactols with high yields and enantioselectivities. The products could be easily transformed into complex trisubstituted γ-lactones and γ-lactams.

  8. An irresolute linker: separation, and structural and spectroscopic characterization of the two linkage isomers of a Ru(ii)-(2-(2'-pyridyl)pyrimidine-4-carboxylic acid) complex.

    Science.gov (United States)

    Iengo, E; Demitri, N; Balducci, G; Alessio, E

    2014-08-28

    For the first time the two linkage isomers of a Ru(ii) complex with 2-(2'-pyridyl)pyrimidine-4-carboxylic acid (cppH) - that form in comparable amounts - have been fully characterized individually. The X-ray structure of each isomer is related to its NMR spectrum in solution.

  9. Polymethyl methacrylate-co-methacrylic acid coatings with controllable concentration of surface carboxyl groups: A novel approach in fabrication of polymeric platforms for potential bio-diagnostic devices

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Samira; Ibrahim, Fatimah [Center for Innovation in Medical Engineering, Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Djordjevic, Ivan, E-mail: ivan.djordjevic@um.edu.my [Center for Innovation in Medical Engineering, Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Koole, Leo H. [Center for Innovation in Medical Engineering, Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Biomedical Engineering, Faculty of Health. Medicine and Life Science, Maastricht University, PO Box 616, NL 6200 MD Maastricht (Netherlands)

    2014-05-01

    Highlights: • Synthesis and processing of PMMA-co-MAA spin-coatings on silicon wafers. • Surface chemistry and morphology as a function of tailored co-polymer structure. • Polymer coatings with controlled number of surface carboxyl groups. - Abstract: The generally accepted strategy in development of bio-diagnostic devices is to immobilize proteins on polymeric surfaces as a part of detection process for diseases and viruses through antibody/antigen coupling. In that perspective, polymer surface properties such as concentration of functional groups must be closely controlled in order to preserve the protein activity. In order to improve the surface characteristics of transparent polymethacrylate plastics that are used for diagnostic devices, we have developed an effective fabrication procedure of polymethylmetacrylate-co-metacrylic acid (PMMA-co-MAA) coatings with controlled number of surface carboxyl groups. The polymers were processed effectively with the spin-coating technique and the detailed control over surface properties is here by demonstrated through the variation of a single synthesis reaction parameter. The chemical structure of synthesized and processed co-polymers has been investigated with nuclear magnetic resonance spectroscopy (NMR) and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-ToF-MS). The surface morphology of polymer coatings have been analyzed with atomic force microscopy (AFM) and scanning electron microscopy (SEM). We demonstrate that the surface morphology and the concentration of surface –COOH groups (determined with UV–vis surface titration) on the processed PMMA-co-MAA coatings can be precisely controlled by variation of initial molar ratio of reactants in the free-radical polymerization reaction. The wettability of developed polymer surfaces also varies with macromolecular structure.

  10. Rhodium-catalyzed regioselective olefination directed by a carboxylic group.

    Science.gov (United States)

    Mochida, Satoshi; Hirano, Koji; Satoh, Tetsuya; Miura, Masahiro

    2011-05-06

    The ortho-olefination of benzoic acids can be achieved effectively through rhodium-catalyzed oxidative coupling with alkenes. The carboxylic group is readily removable to allow ortho-olefination/decarboxylation in one pot. α,β-Unsaturated carboxylic acids such as methacrylic acid also undergo the olefination at the β-position. Under the rhodium catalysis, the cine-olefination of heteroarene carboxylic acids such as thiophene-2-carboxylic acid proceeds smoothly accompanied by decarboxylation to selectively produce the corresponding vinylheteroarene derivatives. © 2011 American Chemical Society

  11. Evaluation of the physico-chemical properties of acid thinned ...

    African Journals Online (AJOL)

    From the investigation, the acid modification of cassava starch at 60°C with 0.1M hydrochloric acid solutions for 1hr and 2hr gave pastes that are stable, and have workable viscosities and can form gel in food processing. Therefore, the results suggest that they are suitable for the food industry as food emulsifiers/stabilizers.

  12. Accumulation and Transport of 1-Aminocyclopropane-1-Carboxylic Acid (ACC) in Plants: Current Status, Considerations for Future Research and Agronomic Applications

    Science.gov (United States)

    Vanderstraeten, Lisa; Van Der Straeten, Dominique

    2017-01-01

    1-aminocyclopropane-1-carboxylic acid (ACC) is a non-protein amino acid acting as the direct precursor of ethylene, a plant hormone regulating a wide variety of vegetative and developmental processes. ACC is the central molecule of ethylene biosynthesis. The rate of ACC formation differs in response to developmental, hormonal and environmental cues. ACC can be conjugated to three derivatives, metabolized in planta or by rhizobacteria using ACC deaminase, and is transported throughout the plant over short and long distances, remotely leading to ethylene responses. This review highlights some recent advances related to ACC. These include the regulation of ACC synthesis, conjugation and deamination, evidence for a role of ACC as an ethylene-independent signal, short and long range ACC transport, and the identification of a first ACC transporter. Although unraveling the complex mechanism of ACC transport is in its infancy, new questions emerge together with the identification of a first transporter. In the light of the future quest for additional ACC transporters, this review presents perspectives of the novel findings and includes considerations for future research toward applications in agronomy. PMID:28174583

  13. [Simultaneous determination of 1-sulfo-cyclohexane carboxylic acid and sulfate anion in the by-products of caprolactam by high performance liquid chromatography-indirect photometric analysis].

    Science.gov (United States)

    Yan, Zhixiang; Duan, Zhengkang; Li, Linan; Li, Haitao; Chen, Qiuyun; Peng, Ye

    2013-02-01

    An improved anion-exchange chromatographic method was developed for simultaneous quantification of 1-sulfo-cyclohexane carboxylic acid (SCCA) and sulfate anion in the by-products of caprolactam. An strong anion chromatographic column and an ultraviolet (UV) detector were chosen for the assay of SCCA and sulfate anion. Non-chromophore-containing sulfate anion is not directly adaptable to the commonly used ultraviolet detection of high performance liquid chromatography (HPLC). This paper reports the development and validation of an HPLC assay for SCCA and sulfate anion based on indirect ultraviolet detection. An ultraviolet-absorbing reagent (the probe), phthalic acid (PA), was added to the mobile phase to induce a signal for the compound. The proposed method was qualified based on the performance criteria of repeatability, intermediate precision and linearity. The limits of detection were 1.0 g/L for both the analytes. The linear ranges varied from 0.50 to 40.0 g/L for SCCA and from 0.10 to 10.0 g/L for sulfate anion, with the correlation coefficients of 0. 999 97 and 0.999 14, and the recoveries of 93.33%-97.40% and 98.50%-101.00%, respectively. The established method can be used in practice to determine SCCA and sulfate anion simultaneously with perfect separation selectivity.

  14. Synthesis and evaluation of 1-hydroxy/methoxy-4-methyl-2-phenyl-1H-imidazole-5-carboxylic acid derivatives as non-purine xanthine oxidase inhibitors.

    Science.gov (United States)

    Chen, Shaolei; Zhang, Tingjian; Wang, Jian; Wang, Fangyang; Niu, Handong; Wu, Chunfu; Wang, Shaojie

    2015-10-20

    Xanthine oxidase is a key enzyme that catalyses hypoxanthine and xanthine to uric acid, whose overproduction leads to the gout-causing hyperuricemia. In this study, a series of 1-hydroxy/methoxy-4-methyl-2-phenyl-1H-imidazole-5-carboxylic acid derivatives (4a-4k and 6a-6k) was synthesized and evaluated for their inhibitory potency against xanthine oxidase. The 1-hydroxyl substituted derivatives 4a-4k showed excellent inhibitory potency with IC50 values ranging from 0.003 μM to 1.2 μM, with compounds 4d (IC₅₀ = 0.003 μM), 4e (IC₅₀ = 0.003 μM), and 4f (IC₅₀ = 0.006 μM) manifesting the most potent xanthine oxidase inhibitory potency that were comparable with that of Febuxostat (IC₅₀ = 0.01 μM). Lineweaver-Burk plot analysis revealed that representative compound 4f acted as a mixed-type inhibitor for xanthine oxidase. The basis of significant inhibition of xanthine oxidase by 4f was rationalized by its molecular docking into the active site of xanthine dehydrogenase. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  15. Synthesis, characterization, X-ray crystallography, and cytotoxicity of a cymantrene keto carboxylic acid for IR labelling of bioactive peptides on a solid support.

    Science.gov (United States)

    Peindy N'Dongo, Harmel W; Neundorf, Ines; Merz, Klaus; Schatzschneider, Ulrich

    2008-12-01

    Cym-CO-CH2-CH2-COOH was prepared in good yield by Friedel-Crafts reaction of cymantrene (Cym, CpMn(CO)3) with succinic anhydride for the IR labelling of peptides and fully characterized, including an X-ray structure analysis (monoclinic space group P2(1)/n, a=5.727(3)A, b=19.865(9)A, c=10.518(5)A, beta=91.211(9) degrees). The compound was isolated in pure form without the need for chromatographic work-up and subsequently used for solution-phase synthesis of a bioconjugate with phenylalanine methyl ester to allow a complete spectroscopic characterization of this model system. The cymantrene keto carboxylic acid also turned out to be a very robust marker in automated microwave-assisted solid phase peptide synthesis (SPPS). [Leu5]-enkephalin (Tyr-Gly-Gly-Phe-Leu) was prepared on a Wang resin and labelled with the cymantrene derivative on the solid support under microwave irradiation in all steps. The metal-carbonyl marker stayed intact during cleavage from the resin with concentrated trifluoroacetic acid. After simple precipitation and lyophilization, the cymantrene-enkephalin bioconjugate could be obtained in analytically pure form without the need of HPLC purification. As required, the compound is non-cytotoxic against MCF-7 cells at up to 100 microM. This protocol thus allows one to introduce organometallic IR spectroscopic labels to peptides in a very straightforward way.

  16. Synthesis and characterization of novel sulfonated poly(arylene ether ketone) copolymers with pendant carboxylic acid groups for proton exchange membranes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yang; Zhao, Chengji; Shao, Ke; Li, Hongtao; Fu, Tiezhu; Na, Hui [Alan G MacDiarmid Institute, College of Chemistry, Jilin University, Changchun 130012 (China); Cui, Zhiming; Xing, Wei [Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China)

    2009-06-15

    A series of novel side-chain-type sulfonated poly(arylene ether ketone)s with pendant carboxylic acid groups copolymers (C-SPAEKs) were synthesized by direct copolymerization of sodium 5,5'-carbonyl-bis(2-fluorobenzenesulfonate), 4,4'-difluorobenzophenone and 4,4'-bis(4-hydroxyphenyl) valeric acid (DPA). The expected structure of the sulfonated copolymers was confirmed by FT-IR and {sup 1}H NMR. Membranes with good thermal and mechanical stability could be obtained by solvent cast process. It should be noted that the proton conductivity of these copolymers with high sulfonatation degree (DS > 0.6) was higher than 0.03 S cm{sup -1} and increased with increasing temperature. At 80 C, the conductivity of C-SPAEK-3 (DS = 0.6) and C-SPAEK-4 (DS = 0.8) reached up to 0.12 and 0.16 S cm{sup -1}, respectively, which were higher than that of Nafion 117 (0.10 S cm{sup -1}). Moreover, their methanol permeability was much lower than that of Nafion 117. These results showed that the synthesized materials might have potential applications as the proton exchange membranes for DMFCs. (author)

  17. Perfluoroalkyl sulfonic and carboxylic acids: a critical review of physicochemical properties, levels and patterns in waters and wastewaters, and treatment methods.

    Science.gov (United States)

    Rayne, Sierra; Forest, Kaya

    2009-10-01

    Perfluorinated acids (PFAs) are an emerging class of environmental contaminants present in various environmental and biological matrices. Two major PFA subclasses are the perfluorinated sulfonic acids (PFSAs) and carboxylic acids (PFCAs). The physicochemical properties and partitioning behavior for the linear PFA members are poorly understood and widely debated. Even less is known about the numerous branched congeners with varying perfluoroalkyl chain lengths, leading to confounding issues around attempts to constrain the properties of PFAs. Current computational methods are not adequate for reliable multimedia modeling efforts and risk assessments. These compounds are widely present in surface, ground, marine, and drinking waters at concentrations that vary from pg L(-1) to microg L(-1). Concentration gradients of up to several orders of magnitude are observed in all types of aquatic systems and reflect proximity to known industrial sources concentrated near populated regions. Some wastewaters contain PFAs at mg L(-1) to low g L(-1) levels, or up to 10 orders of magnitude higher than present in more pristine receiving waters. With the exception of trifluoroacetic acid, which is thought to have both significant natural and anthropogenic sources, all PFSAs and PFCAs are believed to arise from human activities. Filtration and sorption technologies offer the most promising existing removal methods for PFAs in aqueous waste streams, although sonochemical approaches hold promise. Additional studies need to be conducted to better define opportunities from evaporative, extractive, thermal, advanced oxidative, direct and catalyzed photochemical, reductive, and biodegradation methods. Most PFA treatment methods exhibit slow kinetic profiles, hindering their direct application in conventional low hydraulic residence time systems.

  18. Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

    2011-08-01

    Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

  19. Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

    International Nuclear Information System (INIS)

    Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

    2011-01-01

    Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

  20. Study of the behavior of copolymers N-vinylpyrrolidone with unsaturated carboxylic acids and their interactions with surfactants

    International Nuclear Information System (INIS)

    Samarova, O.E.; Ushakova, V.N.; Kipper, A.I.; Panarin, E.F.

    1996-01-01

    Copolymers of N-vinylpyrrolidone with acrylic or undecylenic acid were synthesized by radical and radiation-induced polymerizations. The behaviour of the corresponding polyions in aqueous solutions was studied by light scattering and viscometry. 5 refs.; 2 figs.; 2 tabs

  1. The transport of carboxylic acids and important role of the Jen1p transporter during the development of yeast colonies

    Czech Academy of Sciences Publication Activity Database

    Paivo, S.; Strachotová, Dita; Kučerová, Helena; Hlaváček, Otakar; Mota, A.; Casal, M.; Palková, Z.; Váchová, Libuše

    2013-01-01

    Roč. 454, SEP 2013 (2013), s. 551-558 ISSN 0264-6021 R&D Projects: GA ČR GA204/08/0718 Institutional support: RVO:61388971 Keywords : ammonia production * Jen1p protein * monocarboxylic acid import Subject RIV: CE - Biochemistry Impact factor: 4.779, year: 2013

  2. Free and esterified aliphatic carboxylic acids in humin and humic acids from a peat sample as revealed by pyrolysis with tetramethylammonium hydroxide or tetrathylammonium acetate

    Energy Technology Data Exchange (ETDEWEB)

    Grasset, L.; Guignard, C.; Ambles, A. [UMR 6514, Faculte des Sciences, Poitiers (France). Lab. de Synthese et Reactivite Substances Naturelles

    2002-07-01

    The combination of TMAH thermochemolysis and TEAAc treatment makes it possible to discriminate between the different forms of mono- and dicarboxylic acids present in the structure of humin and humic acids, that is, ''free'' uncombined acids, methyl or ethyl esters present as tightly trapped molecules within the matrix, or acids chemically linked to the matrix by ester groups. The results confirm that ester groups are involved in the structure of humin and humic acids. The cross-linking of moieties originating from microbial metabolism or inherited from higher plants is partly ensured by these chemical groups. On the other hand, significant amounts of fatty monocarboxylic acids and linear dicarboxylic acids are present as free acids in the humin of the studied sample. Humin contains also fatty acid methyl esters. Free, uncombined {alpha},{omega}-dicarboxylic acids were only found in humin. (author)

  3. Seven new Zn(II)/Cd(II) coordination polymers with 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid: Synthesis, structures and properties

    Science.gov (United States)

    Wang, Xin-Fang; Zhou, Sheng-Bin; Du, Ceng-Ceng; Wang, Duo-Zhi; Jia, Dianzeng

    2017-08-01

    Using a new simi-rigid multitopic ligand 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid (H2L), seven new coordination polymers [Zn3(L)2(μ2-OH)2]n (1), {[Zn2(HL)2(H2O)2]·SiF6}n (2), [Zn(HL)(SCN)]n (3), {[Zn2(HL)2(SO4)]·(4,4‧-bpy)}n (4) [4,4‧-bpy =4,4‧-bipyridine], {[Zn(HL)2]·2H2O}n (5), {[Cd(HL)2]·2H2O}n (6) and [Cd2(HL)2(H2O)2(SO4)]n (7) have been successfully obtained from H2L ligand under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and IR spectroscopy. In addition, UV-vis diffuse-reflectance spectra demonstrate wide band gaps. Complex 1 features a 3D topological net of {412·63} with the stoichiometry (6-c), contains 1D channels with the accessible solvent volume of 42.1%. 3, 4, 5 and 6 have a 1D chain structure, 5 and 6 further assemble to form 2D sheet and 3D supramolecular frameworks by hydrogen-bonding interactions, respectively. Complexes 2 and 7 possess a 2D layered structure, and the 2D supramolecular network of 2 can be rationalized to be four-connected {44·62} topological sql network with the dinuclear units, while 7 shows a 3-nodal 2D net with a point symbol of {63}. Moreover, the fluorescent emission, fluorescence lifetimes of 1-7 have been investigated and discussed. Interesting enough, complex 1 showed high efficiency for catalyzing the Knoevenagel condensation reaction between 4-substituted aromatic aldehydes and malononitrile as selective heterogeneous catalyst. The CPs combining catalytic and fluorescent properties could further meet the requirement as a multifunctional material. Seven new Zn(II)/Cd(II) coordination polymers with simi-rigid multitopic ligand, [(2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid) (H2L)] have been successfully obtained and structurally characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and IR

  4. Allosteric coextraction of sodium and metal ions with calix[4]arene derivatives 2: first numerical evaluation for the allosteric effect on alkali metal extraction with crossed carboxylic acid type calix[4]arenes.

    Science.gov (United States)

    Yoneyama, Tomoaki; Sadamatsu, Hirotoshi; Kuwata, Shigemasa; Kawakita, Hidetaka; Ohto, Keisuke

    2012-01-15

    Crossed carboxylic acid types of calix[4]arene derivatives with two longer carboxylic acids and two acetic acids at the distal position have been prepared to investigate the solvent extraction of three alkali metal ions in individual and competitive systems. These extractants selectively extracted sodium ions among other alkali ions at low pH, and the first extracted sodium ion acted as a "trigger" causing a change in extraction ability and metal selectivity. Spacer groups with different lengths induced significant differences in the extraction behavior. The extraction equilibrium constants, K(ex1) and K(ex2), between the present cyclic tetramers and the extracted two alkali metal ions were estimated in order to obtain a numerical evaluation of the allosteric effect. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Tetrazole and triazole as bioisosteres of carboxylic acid: discovery of diketo tetrazoles and diketo triazoles as anti-HCV agents.

    Science.gov (United States)

    Song, Wu-Hui; Liu, Ming-Ming; Zhong, Dong-Wei; Zhu, Ye-lin; Bosscher, Mike; Zhou, Lu; Ye, De-Yong; Yuan, Zheng-Hong

    2013-08-15

    A series of diketo tetrazoles and diketo triazoles were designed and synthesized as bioisosteres of α,γ-diketo acid, the active site inhibitor of HCV (Hepatitis C virus) polymerase NS5B. Among the synthesized compounds, 4-(4-fluorobenzyloxy)phenyl diketo triazole (30) exhibited anti-HCV activity with an EC50 value of 3.9 μM and an SI value more than 128. The reduction of viral protein and mRNA levels were also validated, supporting the anti-HCV activity of compound 30. These results provide convincing evidence that the diketo tetrazoles and diketo triazoles can be developed as bioisosteres of α,γ-diketo acid to exhibit potent inhibitory activity against HCV. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Optimization of SPE/GC/HPLC Analytical Procedure for Determination of Phenol, Quinones, and Carboxylic Acids in Water Samples

    OpenAIRE

    Bielicka-Daszkiewicz, Katarzyna; Hadzicka, Monika; Voelkel, Adam

    2012-01-01

    Chromatographic techniques are among the most useful analytical methods. Gas and liquid chromatography were used in the analysis of some organic compounds: phenol, hydroquinone, benzoquinone, and maleic and fumaric acids. The analytical way for the determination of these compounds in water samples was investigated. Solid-phase extraction (SPE) technique was used on the sample preparation step, different divinylbenzene-based sorbents were applied. Calibration curves of given compounds were lin...

  7. Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions, alkyl iodides, and sulfonamide groups

    OpenAIRE

    Sierra Rayne; Kaya Forest

    2009-01-01

    Temperature dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the SN1 and SN2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degr...

  8. Synthesis, characterization and biological evaluation of novel diesters of 4,4'-dihydroxy azoxy benzene with long chain carboxylic acid

    International Nuclear Information System (INIS)

    Shehzadi, S.; Siddiqi, H.M.; Qasim, M.M.

    2014-01-01

    Synthesis of novel symmetrical azoxy diesters have been prepared by the reaction of 4,4'-dihydroxyazoxy benzene with aliphatic acid halides of varying chain lengths. The synthesized compounds have been characterized by spectral and analytical means. These symmetrical azoxy diesters exhibit good antifungal against six fungal strains (Mucor species, Aspergillus niger, Aspergillus flavus, Alternaria solani, Fusarium solani and Aspergillus fumigatus) and antitumor activities while no significant antibacterial activity has been observed. These synthesized compounds are also potent free radical scavengers. (author)

  9. Emission of perfluoroalkyl carboxylic acids (PFCA) from heated surfaces made of polytetrafluoroethylene (PTFE) applied in food contact materials and consumer products.

    Science.gov (United States)

    Schlummer, Martin; Sölch, Christina; Meisel, Theresa; Still, Mona; Gruber, Ludwig; Wolz, Gerd

    2015-06-01

    Polytetrafluoroethylene (PTFE) has been widely discussed as a source of perfluorooctanoic acid (PFOA), which has been used in the production of fluoropolymers. PTFE may also contain unintended perfluoroalkyl carboxylic acids (PFCAs) caused by thermolysis of PTFE, which has been observed at temperatures above 300°C. Common PTFE coated food contact materials and consumer goods are operated at temperatures above 200°C. However, knowledge on possible emissions of PFCAs is limited. Therefore, it was the aim of this study to investigate and evaluate the emission of PFCAs from PTFE coated products with both, normal use and overheating scenarios. Four pans, claimed to be PFOA free, and nine consumer products were investigated. At normal use conditions (PTFE surfaces were trapped for 1h. Overheating scenarios (>260°C) recorded emissions during a 30min heating of empty pans on a stove. Emissions were analyzed by LC-ESI-MS. Results indicate the emission of PFCAs, whereas no perfluorinated sulfonic acids were traced. At normal use conditions total emissions of PFCAs accounted for 4.75ng per hour. Overheated pans, however, released far higher amounts with up to 12190ng PFCAs per hour at 370°C. Dominating contributors where PFBA and PFOA at normal use and PFBA and PFPeA during overheating. Temperature seems to be the main factor controlling the emission of PFCAs. A worst case estimation of human exposure revealed that emissions of PFCAs from heated PTFE surfaces would be far below the TDI of 1500ng PFOA per kg body weight. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHIC DETERMINATION OF CAFFEIC ACID AND ROSMARINIC ACID FROM THE LEAVES OF Orthosiphon stamineus

    Directory of Open Access Journals (Sweden)

    M. Amzad Hossain

    2010-06-01

    Full Text Available This paper presents the studies performed on extraction of Orthosiphon stamineus, Benth by using different solvent for the identification and quantification of the caffeic acid derivatives such as caffeic acid  and rosmarinic acid which confers to the leaves of this plant with remarkable pharmaceutical properties. High performance thin-layer chromatographic (HPTLC allows the identification and the quantification of more than 20 samples in the same chromatographic run. The analysis of the samples requires 15-30 min compared with more than 2 h using a typical HPLC method. Using the techniques of the HPTLC and the UV-VIS spectra we have found that the extraction of this herb plant contain, the caffeic acid and rosmarinic acid ranging between 0.029% up to 0.506% and up to 0.24% to 2.24% respectively.     Keywords: Caffice acid derivatives, quantification, Malaysian Orthosiphon stamineus, HPTLC

  11. Organotin(IV) carboxylates based on 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetic acid: Syntheses, crystal structures, luminescent properties and antitumor activities

    Science.gov (United States)

    Xiao, Xiao; Liang, Jingwen; Xie, Jingyi; Liu, Xin; Zhu, Dongsheng; Dong, Yuan

    2017-10-01

    Organotin carboxylates based on an amide carboxylic acid 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetic acid (HL): [(Bn2Sn)2O2L]2·2C6H6 (1) (Bn = benzyl group) and (Ph2Sn)(L)2 (2) were synthesized and characterized by elemental analysis, IR, 1H, 13C, 119Sn NMR spectroscopy and X-ray crystallography diffraction analysis. Complex 1 is dimeric carboxylate tetraorganodistannoxane and show a "ladder-like" molecular structure. Complex 2 is a dialkyltin carboxylate monomer possessing crystallographically imposed two-fold symmetry. Ligand in 1 and 2 adopts unidentate and bidentate coordination respectively. Both 1 and 2 form 1D, 2D and 3D supramolecular organizations in the solid state mediated through Csbnd H⋯O and π⋯π interactions which are discussed in detail. The luminescent properties and preliminary antitumor activities about this series of complexes were also studied.

  12. Properties of the Surface Layer of Thin Films of Polyaniline Doped With Phosphoric Acid

    Directory of Open Access Journals (Sweden)

    Almedina Modrić-Šahbazović

    2016-08-01

    Full Text Available This study deals with estimation of the surface free energy of thin films of polyaniline doped with phosphoric acid, by measuring contact angles. Synthesis of polyaniline (PANI with phosphoric acid (PA was performed at room temperature of 20°C, and at 0°C. Thin films were obtained by means of a spin coater, applying the synthetized mixture on a glass substrate. By measuring the contact angle, first between ethylene glycol and a film and then between distilled water and a film, we thus calculated the polar, dispersion and total surface free energy. It was proved and demonstrated that the surface free energy depends on the temperature at which the solution (from which the thin films are obtained later was synthesized.

  13. The PROCESS experiment: amino and carboxylic acids under Mars-like surface UV radiation conditions in low-earth orbit.

    Science.gov (United States)

    Noblet, Audrey; Stalport, Fabien; Guan, Yuan Yong; Poch, Olivier; Coll, Patrice; Szopa, Cyril; Cloix, Mégane; Macari, Frédérique; Raulin, Francois; Chaput, Didier; Cottin, Hervé

    2012-05-01

    The search for organic molecules at the surface of Mars is a top priority of the next Mars exploration space missions: Mars Science Laboratory (NASA) and ExoMars (ESA). The detection of organic matter could provide information about the presence of a prebiotic chemistry or even biological activity on this planet. Therefore, a key step in interpretation of future data collected by these missions is to understand the preservation of organic matter in the martian environment. Several laboratory experiments have been devoted to quantifying and qualifying the evolution of organic molecules under simulated environmental conditions of Mars. However, these laboratory simulations are limited, and one major constraint is the reproduction of the UV spectrum that reaches the surface of Mars. As part of the PROCESS experiment of the European EXPOSE-E mission on board the International Space Station, a study was performed on the photodegradation of organics under filtered extraterrestrial solar electromagnetic radiation that mimics Mars-like surface UV radiation conditions. Glycine, serine, phthalic acid, phthalic acid in the presence of a mineral phase, and mellitic acid were exposed to these conditions for 1.5 years, and their evolution was determined by Fourier transform infrared spectroscopy after their retrieval. The results were compared with data from laboratory experiments. A 1.5-year exposure to Mars-like surface UV radiation conditions in space resulted in complete degradation of the organic compounds. Half-lives between 50 and 150 h for martian surface conditions were calculated from both laboratory and low-Earth orbit experiments. The results highlight that none of those organics are stable under low-Earth orbit solar UV radiation conditions.

  14. Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

    Science.gov (United States)

    Clark, Daniel D.

    2007-01-01

    Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

  15. Sensitive Thin-Layer Chromatography Detection of Boronic Acids Using Alizarin

    NARCIS (Netherlands)

    Duval, F.L.; Beek, van T.A.; Zuilhof, H.

    2012-01-01

    A new method for the selective and sensitive detection of boronic acids on thin-layer chromatography plates is described. The plate is briefly dipped in an alizarin solution, allowed to dry in ambient air, and observed under 366 nm light. Alizarin emits a bright yellow fluorescence only in the

  16. Micromachined Dense Palladium Electrodes for Thin-film Solid Acid Fuel Cells

    NARCIS (Netherlands)

    Unnikrishnan, S.

    2009-01-01

    This thesis paves the way towards the microfabrication of a solid acid electrolyte based fuel cell (µSAFC), which has a membrane electrode assembly (MEA) consisting of a thin-film of water soluble electrolyte encapsulated between two dense palladium electrode membranes. This project work

  17. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

    Science.gov (United States)

    2016-01-01

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr2+, Fe3+, Nd3+, and Am3+, from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  18. Synthesis and Characterization of a Heteroleptic Ru(II Complex of Phenanthroline Containing Oligo-Anthracenyl Carboxylic Acid Moieties

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    2010-09-01

    Full Text Available In an effort to develop new ruthenium(II complexes, this work describes the design, synthesis and characterization of a ruthenium(II functionalized phenanthroline complex with extended π-conjugation. The ligand were L1 (4,7-bis(2,3-dimethylacrylic acid-1,10-phenanthroline, synthesized by a direct aromatic substitution reaction, and L2 (4,7-bis(trianthracenyl-2,3-dimethylacrylic acid-1,10-phenanthroline, which was synthesized by the dehalogenation of halogenated aromatic compounds using a zero-valent palladium cross-catalyzed reaction in the absence of magnesium-diene complexes and/or cyclooctadienyl nickel (0 catalysts to generate a new carbon-carbon bond (C-C bond polymerized hydrocarbon units. The ruthenium complex [RuL1L2(NCS2] showed improved photophysical properties (red-shifted metal-to-ligand charge-transfer transition absorptions and enhanced molar extinction coefficients, luminescence and interesting electrochemical properties. Cyclic and square wave voltammetry revealed five major redox processes. The number of electron(s transferred by the ruthenium complex was determined by chronocoulometry in each case. The results show that processes I, II and III are multi-electron transfer reactions while processes IV and V involved one-electron transfer reaction. The photophysical property of the complex makes it a promising candidate in the design of chemosensors and photosensitizers, while its redox-active nature makes the complex a potential mediator of electron transfer in photochemical processes.

  19. Synthesis, structures and properties of Cu(II) and Mn(II) complexes with 1,10-phenanthroline-2-carboxylic acid and 2,2'-bipyridine ligands.

    Science.gov (United States)

    Sun, Jingya; Xu, Huanzhi

    2010-11-15

    Four new 2,2'-bipyridine and 1,10-phenanthroline complexes, namely [Mn(phenca)(2)]·(H(2)O)(2) (1), [Cu(4)(phen)(4)(OH-)(4)(H(2)O)(2)](DMF)(4)(ClO(4)-)(4)(H(2)O) (2), [Cu(2)(2,2-bipy)(2)(C(2)O(4)2-)(H(2)O)(2)(NO(3))(2)] (3) and [Cu(2,2-bipy)(2)(ClO(4)-)](ClO(4)-) (4) (2,2'-bpy = 2,2'-bipyridine, Hphenca = 1,10-phenanthroline-2-carboxylic acid) have been synthesized by a hydrothermal reaction. The products were characterized by elemental analysis, infrared spectroscopy and X-ray crystal diffraction. While strong hydrogen bonds play central roles in the formation of the 3D structure, the combined influence of the weak interactions such as π···π interactions is also evident in the structures. A preliminary investigation on the ion exchange properties of the complexes is presented.

  20. Better Rooting Procedure to Enhance Survival Rate of Field Grown Malaysian Eksotika Papaya Transformed with 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Gene

    Science.gov (United States)

    Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom

    2013-01-01

    A high survival rate for transformed papaya plants when transferred to the field is useful in the quest for improving the commercial quality traits. We report in this paper an improved rooting method for the production of transformed Malaysian Eksotika papaya with high survival rate when transferred to the field. Shoots were regenerated from embryogenic calli transformed with antisense and RNAi constructs of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes using the Agrobacterium tumefaciens-mediated transformation method. Regenerated transformed shoots, each measuring approximately 3-4 cm in height, were cultured in liquid half-strength Murashige and Skoog (MS) medium or sterile distilled water, and with either perlite or vermiculite supplementation. All the culturing processes were conducted either under sterile or nonsterile condition. The results showed that rooting under sterile condition was better. Shoots cultured in half-strength MS medium supplemented with vermiculite exhibited a 92.5% rooting efficiency while perlite showed 77.5%. The survival rate of the vermiculite-grown transformed papaya plantlets after transfer into soil, contained in polybags, was 94%, and the rate after transfer into the ground was 92%. Morpho-histological analyses revealed that the tap roots were more compact, which might have contributed to the high survival rates of the plantlets. PMID:25969786

  1. Fast quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCA) using microwave-accelerated derivatisation and gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    De Brabanter, Nik; Van Gansbeke, Wim; Hooghe, Fiona; Van Eenoo, Peter

    2013-01-10

    A rapid and sensitive determination of cannabinoids in urine is important in many fields, from workplace drug testing over toxicology to the fight against doping. The detection of cannabis abuse is normally based on the quantification of the most important metabolite 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCA) in urine. In most fields THCA needs to be present at a concentration of exceeding 15ng/mL before a positive result can be reported. The method described in this paper, combines a 4min GC-MS/MS method with a fast sample preparation procedure using microwave assisted derivatisation in order to complete the quantification of THCA in urine in 30min, using only 1mL of urine. The method is selective, linear over the range 5-100ng/mL and shows excellent precision and trueness and hence, the estimated measurement uncertainty at the threshold level is small. The method also complies with applicable criteria for mass spectrometry and chromatography. Therefore the method can be used for rapid screening and confirmatory purposes. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Rapid Detection of Ascorbic Acid Based on a Dual-Electrode Sensor System Using a Powder Microelectrode Embedded with Carboxyl Multi-Walled Carbon Nanotubes.

    Science.gov (United States)

    He, Bao-Shan; Zhang, Jun-Xia

    2017-07-02

    In this paper, carboxyl groups were introduced by liquid oxidation methods onto multi-walled carbon nanotubes (MWCNTs) to improve the MWCNTs' electrocatalytic properties. A platinum wire microelectrode (ME) was corroded using aqua regia and subsequently embedded with MWCNTs to achieve more active sites, producing a so-called powder microelectrode (PME). Compared with conventional MEs, the PME has a larger specific surface area and more active sites. When PME was used to detect ascorbic acid (AA), the AA oxidation potential shifted negatively and current peak was visibly increased. The calibration curve obtained for AA was in a range of 5.00 × 10 -6 ~9.50 × 10 -4 mol·L -1 : I pa (μA) = 3.259 × 10 -2 + 1.801 × 10² C (mol·L -1 ) under the optimum testing conditions. Moreover, the detection and quantitation limits were confirmed at 4.89 × 10 -7 mol·L -1 and 1.63 × 10 -7 mol·L -1 , respectively. When the fabricated PME was practically applied to detect AA, it was shown a recovery rate of 94~107% with relative standard deviation (RSD) <5%. The proposed strategy thus offers a promising, rapid, selective and low-cost approach to effective analysis of AA.

  3. CatB is Critical for Total Catalase Activity and Reduces Bactericidal Effects of Phenazine-1-Carboxylic Acid on Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola.

    Science.gov (United States)

    Pan, Xiayan; Wu, Jian; Xu, Shu; Duan, Yabing; Zhou, Mingguo

    2017-02-01

    Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, and rice bacterial leaf streak, caused by X. oryzae pv. oryzicola, are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species in X. oryzae pv. oryzae. In this study, we found that PCA significantly upregulated the transcript levels of catB and katE, which encode catalases, and that PCA sensitivity was reduced when X. oryzae pvs. oryzae and oryzicola were cultured with exogenous catalase. Furthermore, catB deletion mutants of X. oryzae pvs. oryzae and oryzicola showed dramatically decreased total catalase activity, increased sensitivity to PCA, and reduced virulence in rice. In contrast, deletion mutants of srpA and katG, which also encode catalases, exhibited little change in PCA sensitivity. The results indicate that catB in both X. oryzae pvs. oryzae and oryzicola encodes a catalase that helps protect the bacteria against PCA-induced stress.

  4. Detection of the marijuana metabolite 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in oral fluid specimens and its contribution to positive results in screening assays.

    Science.gov (United States)

    Moore, Christine; Ross, Wayne; Coulter, Cynthia; Adams, Laura; Rana, Sumandeep; Vincent, Michael; Soares, James

    2006-09-01

    The detection of the marijuana metabolite 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in oral fluid specimens is described, and its contribution to an immunoassay for the detection of cannabinoids is investigated. Oral fluid specimens, screened using an enzyme-linked immunosorbent immunoassay (ELISA), were carried forward to confirmation for both tetrahydrocannabinol (THC) and THC-COOH using gas chromatography-mass spectrometry (GC-MS). One hundred and fifty-three specimens were analyzed, of which 143 screened positive for cannabinoids. Ninety-five (66.4%) of these specimens were positive for both THC and THC-COOH; 14 (9.7%) were positive for THC-COOH only, and 27 (18.8%) were positive for THC only. The GC-MS assay for the detection of THC-COOH in oral fluid was linear to 160 pg/mL with a limit of quantitation of 2 pg/mL. The detection of the marijuana metabolite, THC-COOH, in 76.2% of oral fluid specimens screening positive for cannabinoids is reported. As a potential defense against passive exposure claims, proposed SAMHSA regulations may require the simultaneous collection of a urine sample when oral fluid samples are used. The detection of the metabolite, THC-COOH, is a significant alternative to this approach because its presence in oral fluid minimizes the argument for passive exposure to marijuana in drug testing cases.

  5. First-principles investigation of the adsorption of the 2,5-pyridine di-carboxylic acid onto the Cu(011) surface

    Science.gov (United States)

    Tranca, D. C.; Keil, F. J.

    2011-03-01

    First-principles calculations within the density functional theory (DFT) framework have been performed in order to investigate various conformations of the 2,5-pyridine di-carboxylic acid (PDCA) molecule adsorbed onto the Cu(011) surface. By means of DFT calculations the adsorption geometry, the bond formation and the electronic properties of PDCA molecule conformations on the Cu(011) surface have been studied. The most important structural property is the orientation of the COOH H atom which can point either toward the aromatic ring or toward the vacuum. This H atom position determines the possible reactions in which the adsorbed molecule can get involved and also has a significant impact on the value of the Cu-molecule system work function. Thus, we find that simply by changing the H atom orientation (from up to down) the Cu-molecule system work function can be varied with more than 2.5 eV. This is a significant result as a lot of effort is put nowadays in finding efficient ways for the in situ variation of the systems work function. Scanning tunneling microscopy (STM) images, reflexion absorption infrared vibrational spectra (RAIRS) as well as various thermodynamic properties (adsorption entropies, enthalpies) have also been investigated in order to get a better insight into the system studied and to provide support to possible experimental studies (STM or RAIRS experiments).

  6. Localization of tritiated 1-(2, 4-dichlorobenzyl)-1H-indazole-3-carboxylic acid ([3H] AF 1890) in rat testis using freeze-drying autoradiography

    International Nuclear Information System (INIS)

    Hilderbrandt-Stark, H.E.; Mills, J.W.; Fawcett, D.W.

    1982-01-01

    Tritiated 1-(2, 4-dichlorobenzyl)- 1 H-indazole-3-carboxylic acid ([ 3 H]AF 1890) was localized within rat testis using freeze-drying autoradiographic techniques. Ligated seminiferous tubule preparations were exposed in vitro to 80 microCi of [ 3 H]AF 1890 in the absence or presence of excess unlabeled AF 1890 for 30 min at 31 degrees C. Autoradiographs showed a generalized distribution of silver grains over the seminiferous epithelium, in the tubular lumen, and in the interstitial spaces. In addition, clusters of grains were concentrated over the seminiferous epithelium in regions of spermatid heads and tails and in the basal portion of the Sertoli cell cytoplasm, and over Leydig cells in the interstitial space. The generalized distribution was reduced and the grain clusters eliminated by incubation in an excess of unlabeled AF 1890. [ 3 H]inulin was used to assess the effectiveness of the tubular ligation because inulin does not normally penetrate the blood-testis barrier. This extracellular marker was not localized in the tubular lumen or in the seminiferous epithelium. Therefore, the labeling observed with [ 3 H]AF 1890 indicates that this compound crosses the blood-testis barrier

  7. A phenazine-1-carboxylic acid producing polyextremophilic Pseudomonas chlororaphis (MCC2693) strain, isolated from mountain ecosystem, possesses biocontrol and plant growth promotion abilities.

    Science.gov (United States)

    Jain, Rahul; Pandey, Anita

    2016-09-01

    The genus Pseudomonas is known to comprise a huge diversity of species with the ability to thrive in different habitats, including those considered as extreme environments. In the present study, a psychrotolerant, wide pH tolerant and halotolerant strain of Pseudomonas chlororaphis GBPI_507 (MCC2693), isolated from the wheat rhizosphere growing in a mountain location in Indian Himalayan Region (IHR), has been investigated for its antimicrobial potential with particular reference to phenazine production and plant growth promoting traits. GBPI_507 showed phenazine production at the temperatures ranged from 14 to 25°C. The benzene extracted compound identified as phenazine-1-carboxylic acid (PCA) through GC-MS exhibited antimicrobial properties against Gram positive bacteria and actinomycetes. The inhibition of phytopathogens in diffusible biocontrol assays was recorded in an order: Alternaria alternata>Phytophthora sp.>Fusarium solani>F. oxysporum. In volatile metabolite assays, all the pathogens, except Phytophthora sp. produced distorted colonies, characterized by restricted sporulation. The isolate also possessed other growth promoting and biocontrol traits including phosphate solubilization and production of siderophores, HCN, ammonia, and lytic enzymes (lipase and protease). Molecular studies confirmed production of PCA by the bacterium GBPI_507 through presence of phzCD and phzE genes in its genome. The polyextremophilic bacterial strain possesses various important characters to consider it as a potential agent for field applications, especially in mountain ecosystem, for sustainable and eco-friendly crop production. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Development of 2-(Substituted Benzylamino)-4-Methyl-1, 3-Thiazole-5-Carboxylic Acid Derivatives as Xanthine Oxidase Inhibitors and Free Radical Scavengers.

    Science.gov (United States)

    Ali, Md Rahmat; Kumar, Suresh; Afzal, Obaid; Shalmali, Nishtha; Sharma, Manju; Bawa, Sandhya

    2016-04-01

    A series of 2-(substituted benzylamino)-4-methylthiazole-5-carboxylic acid was designed and synthesized as structural analogue of febuxostat. A methylene amine spacer was incorporated between the phenyl ring and thiazole ring in contrast to febuxostat in which the phenyl ring was directly linked with the thiazole moiety. The purpose of incorporating methylene amine was to provide a heteroatom which is expected to favour hydrogen bonding within the active site residues of the enzyme xanthine oxidase. The structure of all the compounds was established by the combined use of FT-IR, NMR and MS spectral data. All the compounds were screened in vitro for their ability to inhibit the enzyme xanthine oxidase as per the reported procedure along with DPPH free radical scavenging assay. Compounds 5j, 5k and 5l demonstrated satisfactory potent xanthine oxidase inhibitory activities with IC50 values, 3.6, 8.1 and 9.9 μm, respectively, whereas compounds 5k, 5n and 5p demonstrated moderate antioxidant activities having IC50 15.3, 17.6 and 19.6 μm, respectively, along with xanthine oxidase inhibitory activity. Compound 5k showed moderate xanthine oxidase inhibitory activity as compared with febuxostat along with antioxidant activity. All the compounds were also studied for their binding affinity in active site of enzyme (PDB ID-1N5X). © 2015 John Wiley & Sons A/S.

  9. Synthesis and evaluation of 1-phenyl-1H-1,2,3-triazole-4-carboxylic acid derivatives as xanthine oxidase inhibitors.

    Science.gov (United States)

    Zhang, Ting-Jian; Wu, Qing-Xia; Li, Song-Ye; Wang, Lin; Sun, Qi; Zhang, Yi; Meng, Fan-Hao; Gao, Hua

    2017-08-15

    This study mainly focused on the modification of the X 2 position in febuxostat analogs. A series of 1-phenyl-1H-1,2,3-triazole-4-carboxylic acid derivatives (1a-s) with an N atom occupying the X 2 position was designed and synthesized. Evaluation of their inhibitory potency in vitro on xanthine oxidase indicated that these compounds exhibited micromolar level potencies, with IC 50 values ranging from 0.21µM to 26.13μM. Among them, compound 1s (IC 50 =0.21μM) showed the most promising inhibitory effects and was 36-fold more potent than allopurinol, but was still 13-fold less potent than the lead compound Y-700, which meant that a polar atom fused at the X 2 position could be unfavorable for potency. The Lineweaver-Burk plot revealed that compound 1s acted as a mixed-type xanthine oxidase inhibitor. Analysis of the structure-activity relationships demonstrated that a more lipophilic ether tail (e.g., meta-methoxybenzoxy) at the 4'-position could benefit the inhibitory potency. Molecular modeling provided a reasonable explanation for the structure-activity relationships observed in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Better rooting procedure to enhance survival rate of field grown malaysian eksotika papaya transformed with 1-aminocyclopropane-1-carboxylic Acid oxidase gene.

    Science.gov (United States)

    Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom

    2013-01-01

    A high survival rate for transformed papaya plants when transferred to the field is useful in the quest for improving the commercial quality traits. We report in this paper an improved rooting method for the production of transformed Malaysian Eksotika papaya with high survival rate when transferred to the field. Shoots were regenerated from embryogenic calli transformed with antisense and RNAi constructs of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes using the Agrobacterium tumefaciens-mediated transformation method. Regenerated transformed shoots, each measuring approximately 3-4 cm in height, were cultured in liquid half-strength Murashige and Skoog (MS) medium or sterile distilled water, and with either perlite or vermiculite supplementation. All the culturing processes were conducted either under sterile or nonsterile condition. The results showed that rooting under sterile condition was better. Shoots cultured in half-strength MS medium supplemented with vermiculite exhibited a 92.5% rooting efficiency while perlite showed 77.5%. The survival rate of the vermiculite-grown transformed papaya plantlets after transfer into soil, contained in polybags, was 94%, and the rate after transfer into the ground was 92%. Morpho-histological analyses revealed that the tap roots were more compact, which might have contributed to the high survival rates of the plantlets.

  11. Saponin Biosynthesis in Saponaria vaccaria. cDNAs Encoding β-Amyrin Synthase and a Triterpene Carboxylic Acid Glucosyltransferase1[OA

    Science.gov (United States)

    Meesapyodsuk, Dauenpen; Balsevich, John; Reed, Darwin W.; Covello, Patrick S.

    2007-01-01

    Saponaria vaccaria (Caryophyllaceae), a soapwort, known in western Canada as cowcockle, contains bioactive oleanane-type saponins similar to those found in soapbark tree (Quillaja saponaria; Rosaceae). To improve our understanding of the biosynthesis of these saponins, a combined polymerase chain reaction and expressed sequence tag approach was taken to identify the genes involved. A cDNA encoding a β-amyrin synthase (SvBS) was isolated by reverse transcription-polymerase chain reaction and characterized by expression in yeast (Saccharomyces cerevisiae). The SvBS gene is predominantly expressed in leaves. A S. vaccaria developing seed expressed sequence tag collection was developed and used for the isolation of a full-length cDNA bearing sequence similarity to ester-forming glycosyltransferases. The gene product of the cDNA, classified as UGT74M1, was expressed in Escherichia coli, purified, and identified as a triterpene carboxylic acid glucosyltransferase. UGT74M1 is expressed in roots and leaves and appears to be involved in monodesmoside biosynthesis in S. vaccaria. PMID:17172290

  12. Silicon Dioxide Thin Film Mediated Single Cell Nucleic Acid Isolation

    Science.gov (United States)

    Bogdanov, Evgeny; Dominova, Irina; Shusharina, Natalia; Botman, Stepan; Kasymov, Vitaliy; Patrushev, Maksim

    2013-01-01

    A limited amount of DNA extracted from single cells, and the development of single cell diagnostics make it necessary to create a new highly effective method for the single cells nucleic acids isolation. In this paper, we propose the DNA isolation method from biomaterials with limited DNA quantity in sample, and from samples with degradable DNA based on the use of solid-phase adsorbent silicon dioxide nanofilm deposited on the inner surface of PCR tube. PMID:23874571

  13. Fluorescence of cis-1-amino-2-(3-indolyl)cyclohexane-1-carboxylic acid: a single tryptophan chi(1) rotamer model.

    Science.gov (United States)

    Liu, Bo; Thalji, Reema K; Adams, Paul D; Fronczek, Frank R; McLaughlin, Mark L; Barkley, Mary D

    2002-11-06

    A constrained derivative, cis-1-amino-2-(3-indolyl)cyclohexane-1-carboxylic acid, cis-W3, was designed to test the rotamer model of tryptophan photophysics. The conformational constraint enforces a single chi(1) conformation, analogous to the chi(1) = 60 degrees rotamer of tryptophan. The side-chain torsion angles in the X-ray structure of cis-W3 were chi(1) = 58.5 degrees and chi(2) = -88.7 degrees. Molecular mechanics calculations suggested two chi(2) rotamers for cis-W3 in solution, -100 degrees and 80 degrees, analogous to the chi(2) = +/-90 degrees rotamers of tryptophan. The fluorescence decay of the cis-W3 zwitterion was biexponential with lifetimes of 3.1 and 0.3 ns at 25 degrees C. The relative amplitudes of the lifetime components match the chi(2) rotamer populations predicted by molecular mechanics. The longer lifetime represents the major chi(2) = -100 degrees rotamer. The shorter lifetime represents the minor chi(2) = 80 degrees rotamer having the ammonium group closer to C4 of the indole ring (labeled C5 in the cis-W3 X-ray structure). Intramolecular excited-state proton transfer occurs at indole C4 in the tryptophan zwitterion (Saito, I.; Sugiyama, H.; Yamamoto, A.; Muramatsu, S.; Matsuura,T. J. Am. Chem. Soc. 1984, 106, 4286-4287). Photochemical isotope exchange experiments showed that H-D exchange occurs exclusively at C5 in the cis-W3 zwitterion, consistent with the presence of the chi(2) = 80 degrees rotamer in solution. The rates of two nonradiative processes, excited-state proton and electron transfer, were measured for individual chi(2) rotamers. The excited-state proton-transfer rate was determined from H-D exchange and fluorescence lifetime data. The excited-state electron-transfer rate was determined from the temperature dependence of the fluorescence lifetime. The major quenching process in the -100 degrees rotamer is electron transfer from the excited indole to carboxylate. Electron transfer also occurs in the 80 degrees rotamer, but the

  14. Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; Martello, Simona; Gottardi, Massimo; Pellegrini, Manuela; Svaizer, Fiorenza; Lotti, Andrea; Chiarotti, Marcello; Pacifici, Roberta

    2015-04-01

    We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 μl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 μl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Photoconductivity study of acid on Zinc phthalocyanine pyridine thin films

    Science.gov (United States)

    Singh, Sukhwinder; Saini, G. S. S.; Tripathi, S. K.

    2016-05-01

    The Metal Phthalocyanine (MPc) have attracted much interest because of chemical and high thermal stability. Molecules forming a crystal of MPc are held together by weak attractive Vander Waals forces. Organic semiconductors have π conjugate bonds which allow electrons to move via π-electron cloud overlaps. Conduction mechanisms for organic semiconductor are mainly through tunneling; hopping between localized states, mobility gaps, and phonon assisted hopping. The photo conductivity of thin films of these complexes changes when exposed to oxidizing and reducing gases. Arrhenius plot is used to find the thermal activation energy in the intrinsic region and impurity scattering region. Arrhenius plotsare used to find the thermal activation energy. The original version of this article supplied to AIP Publishing contained erroneous text at the end of the abstract. "Arrhenius plots are used to find the thermal activation energy." was deleted as it does not pertain to the article. In addition, a figure citation was cited incorrectly and an equation was missing. This has been corrected in the updated version republished on 4 December 2017.

  16. Extraction chromatography of indium (III) on silica gel impregnated with high molecular weight carboxylic acid and its analytical applications

    International Nuclear Information System (INIS)

    Majumdar, P.S.; Ray, U.S.

    1991-01-01

    Indium(III) was separated by extraction chromatography with Versatic 10 as a stationary phase on a column of silica gel from acetic acid and sodium acetate solution (pH 4.5-6.0). The optimum condition for extraction was studied based on the critical study of the relevant factors as effects of pH, flow rate on extraction and elution. Role of stripping agents on the elution was studied. The separation of indium from a number of elements was carried out. Indium(III) was separated from Alsup(III), Gasup(III), Tlsup(III), Zrsup(IV) and trivalent lanthanides which interfere under the recommended extraction condition by exploiting the differences in their stripping behaviour. (author). 7 refs., 1 tab., 1 fig

  17. Effects of 5,8-dimethylthieno[2,3-b]quinoline-2-carboxylic acid on the antioxidative defense and lipid membranes in Plasmodium berghei-infected erythrocytes.

    Science.gov (United States)

    Gamboa de Domínguez, N D; Charris, J; Domínguez, J; Monasterios, M; Angel, J; Rodrigues, J

    2015-08-01

    Plasmodium parasites degrade hemoglobin producing reactive oxygen species as toxic byproducts which are detoxified by a series of antioxidant mechanisms. Quinoline compounds have demonstrated activity against hemoglobin degradation with 5,8-dimethylthieno[2,3-b]quinoline-2-carboxylic acid (TQCA) representing a recent compound inhibiting this process. Thus, this study was undertaken to determine the ability of TQCA to modify the oxidative status in Plasmodium berghei-infected erythrocytes. After hemolysis, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and dehydrogenase enzymes as well as lipid peroxidation were investigated by spectrophotometry. Saturated and unsaturated fatty acids were determined by gas-liquid chromatography and the in vivo effects of TQCA were confirmed by a malaria murine model (Rane test). The activity of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) in infected cells was diminished by this compound compared to control infection in 75.1 ± 3.5% and 26.5 ± 0.3%, respectively, while that of GPx and GR was also lowered (p quinoline derivate in 49.2 ± 1.32% and 37 ± 0.06%, respectively, protecting the cells from hemolysis caused by the infection. The in vitro results were in concordance with the potential in vivo activity of this compound in an established malaria murine model in which TQCA showed significant decrease in the parasitemia levels and increased the mean survival days of infected mice. In conclusion, the antioxidant defense represents a biochemical target for TQCA actions as a potent antimalarial whose effects were also confirmed in vivo. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Arabidopsis acetyl-amido synthetase GH3.5 involvement in camalexin biosynthesis through conjugation of indole-3-carboxylic acid and cysteine and upregulation of camalexin biosynthesis genes.

    Science.gov (United States)

    Wang, Mu-Yang; Liu, Xue-Ting; Chen, Ying; Xu, Xiao-Jing; Yu, Biao; Zhang, Shu-Qun; Li, Qun; He, Zu-Hua

    2012-07-01

    Camalexin (3-thiazol-2'-yl-indole) is the major phytoalexin found in Arabidopsis thaliana. Several key intermediates and corresponding enzymes have been identified in camalexin biosynthesis through mutant screening and biochemical experiments. Camalexin is formed when indole-3-acetonitrile (IAN) is catalyzed by the cytochrome P450 monooxygenase CYP71A13. Here, we demonstrate that the Arabidopsis GH3.5 protein, a multifunctional acetyl-amido synthetase, is involved in camalexin biosynthesis via conjugating indole-3-carboxylic acid (ICA) and cysteine (Cys) and regulating camalexin biosynthesis genes. Camalexin levels were increased in the activation-tagged mutant gh3.5-1D in both Col-0 and cyp71A13-2 mutant backgrounds after pathogen infection. The recombinant GH3.5 protein catalyzed the conjugation of ICA and Cys to form a possible intermediate indole-3-acyl-cysteinate (ICA(Cys)) in vitro. In support of the in vitro reaction, feeding with ICA and Cys increased camalexin levels in Col-0 and gh3.5-1D. Dihydrocamalexic acid (DHCA), the precursor of camalexin and the substrate for PAD3, was accumulated in gh3.5-1D/pad3-1, suggesting that ICA(Cys) could be an additional precursor of DHCA for camalexin biosynthesis. Furthermore, expression of the major camalexin biosynthesis genes CYP79B2, CYP71A12, CYP71A13 and PAD3 was strongly induced in gh3.5-1D. Our study suggests that GH3.5 is involved in camalexin biosynthesis through direct catalyzation of the formation of ICA(Cys), and upregulation of the major biosynthetic pathway genes. © 2012 Institute of Botany, Chinese Academy of Sciences.

  19. High-throughput aided synthesis of the porous metal-organic framework-type aluminum pyromellitate, MIL-121, with extra carboxylic acid functionalization.

    Science.gov (United States)

    Volkringer, Christophe; Loiseau, Thierry; Guillou, Nathalie; Férey, Gérard; Haouas, Mohamed; Taulelle, Francis; Elkaim, Erik; Stock, Norbert

    2010-11-01

    A new porous metal-organic framework (MOF)-type aluminum pyromellitate (MIL-121 or Al(OH)[H(2)btec]·(guest), (guest = H(2)O, H(4)btec = pyromellitic acid) has been isolated by using a high-throughput synthesis method under hydrothermal conditions. Its structure was determined from powder X-ray diffraction analysis using synchrotron radiation (Soleil, France) and exhibits a network closely related to that of the MIL-53 series. It is a three-dimensional (3D) framework containing one-dimensional (1D) channels delimited by infinite trans-connected aluminum-centered octahedra AlO(4)(OH)(2) linked through the pyromellitate ligand. Here the organic ligand acts as tetradendate linker via two of the carboxylate groups. The two others remain non-bonded in their protonated form, and this constitutes a rare case of the occurrence of both bonding and non-bonding organic functionalities of the MOF family. The non-coordinated -COOH groups points toward the channels to get them an open form configuration. Within the tunnels are located unreacted pyromellitic acid and water species, which are evacuated upon heating, and a porous MIL-121 phase is obtained with a Brunauer-Emmett-Teller (BET) surface area of 162 m(2) g(-1). MIL-121 has been characterized by IR, thermogravimetry (TG) analyses, and solid state NMR spectroscopy employing a couple of two-dimensional (2D) techniques such as (1)H-(1)H SQ-DQ BABA, (1)H-(1)H SQ-SQ RFDR, (27)Al{(1)H} CPHETCOR and (27)Al MQMAS.

  20. Influence of carboxylic ion-pairing reagents on retention of peptides in thin-layer chromatography systems with C18 silica-based adsorbents.

    Science.gov (United States)

    Gwarda, Radosław Ł; Aletańska-Kozak, Monika; Klimek-Turek, Anna; Ziajko-Jankowska, Agnieszka; Matosiuk, Dariusz; Dzido, Tadeusz H

    2016-04-01

    One of the main problems related to chromatography of peptides concerns adverse interactions of their strong basic groups with free silanol groups of the silica based stationary phase. Influence of type and concentration of ion-pairing regents on peptide retention in reversed-phase high-performance liquid chromatography (RP-HPLC) systems has been discussed before. Here we present influence of these mobile phase additives on retention of some peptide standards in high-performance thin-layer chromatography (HPTLC) systems with C18 silica-based adsorbents. We prove, that due to different characteristic of adsorbents used in both techniques (RP HPLC and HPTLC), influence of ion-pairing reagents on retention of basic and/or amphoteric compounds also may be quite different. C18 silica-based HPTLC adsorbents provide more complex mechanism of retention and should be rather considered as mixed-mode adsorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Enantioselective Recognition of Chiral Carboxylic Acids by a β-Amino Acid and 1,10-Phenanthroline Based Chiral Fluorescent Sensor

    Directory of Open Access Journals (Sweden)

    Yonghong Zhang

    2015-05-01

    Full Text Available A novel chiral 1,10-phenanthroline-based fluorescent sensor was designed and synthesized from optical active β-amino acids. It used 1,10-phenanthroline moiety as a fluorescent signaling site and binding site, with optically active β-amino acids as a chiral barrier site. Notably, the optically active β-amino acids were obtained by a Lewis base catalyzed hydrosilylation of β-enamino esters according to our former work. The chiral sensor has been used to conduct the enantioselective recognition of chiral mono and dicarboxylic acids derivatives. Using this fluorescent sensor, a moderate “turn-off” fluorescence-diminishment response towards enantiomer of tartaric acids, and proline was observed. It found that l-enantiomers quench the chiral fluorescence sensor more efficiently than d-enantiomers due to the absolute configuration of the β-amino acid.

  2. Key Role of the Carboxyl Terminus of Hyaluronan Synthase in Processive Synthesis and Size Control of Hyaluronic Acid Polymers.

    Science.gov (United States)

    Yang, Ji; Cheng, Fangyu; Yu, Huimin; Wang, Junting; Guo, Zhigang; Stephanopoulos, Gregory

    2017-04-10

    The essential pathophysiological roles of hyaluronic acid (HA) strongly depend on HA binding and HA size. Here we deployed the atomic vision of molecular dynamics (MD) simulation to experimentally investigate the influence of C-terminal mutations of Streptococcus equisimilis hyaluronan synthase (SeHAS) on HA product synthesis in Escherichia coli. R413 was vital for HA production, as the removal or mutation of R413 led to inactivation of SeHAS. MD simulations indicated that R406-R413 constituted an HA-binding pattern that stabilized the HA-SeHAS complex. We further increased HA product size via site-directed mutation of the SeHAS C-terminal residues 414-417 based on the hypothesis that higher binding affinity between the SeHAS C-terminus and HA would lead to larger HA size, underlying the important role of the HA-SeHAS interaction in HA size control. W410A and T412A mutations also completely deactivated SeHAS. Moreover, a catalysis-transformation-translocation model was proposed for the HA synthesis and translocation processes.

  3. Surfactant-Solvent Interaction Effects on the Micellization of Cationic Surfactants in a Carboxylic Acid-Based Deep Eutectic Solvent.

    Science.gov (United States)

    Sanchez-Fernandez, Adrian; Hammond, Oliver S; Jackson, Andrew J; Arnold, Thomas; Doutch, James; Edler, Karen J

    2017-12-19

    Deep eutectic solvents have been demonstrated to support amphiphile self-assembly, providing potential alternatives as structure-directing agents in the synthesis of nanostructures, and drug delivery. Here we have expanded on this recent research to investigate the self-assembly of alkyltrimethylammonium bromide surfactants in choline chloride:malonic acid deep eutectic solvent and mixtures of the solvent with water. Surface tension and small-angle neutron scattering were used to determine the behavior of the amphiphiles. Surfactants were found to remain active in the solvent, and surface tension measurements revealed changes in the behavior of the surfactants with different levels of hydration. Small-angle neutron scattering shows that in this solvent the micelle shape depends on the surfactant chain length, varying from globular micelles (aspect ratio ∼2) for short chain surfactants to elongated micelles (aspect ratio ∼14) for long chain surfactants even at low surfactant concentration. We suggest that the formation of elongated micelles can be explained through the interaction of the solvent with the surfactant headgroup, since ion-ion interactions between surfactant headgroups and solvent may modify the morphology of the micelles. The presence of water in the deep eutectic solvents promotes an increase in the charge density at the micelle interface and therefore the formation of less elongated, globular micelles.

  4. Enantioselective Synthesis of α-Methylene-β-hydroxy Carboxylic Acid Derivatives via a Diastereoselective Aldol-β-Elimination Sequence: Application to the C(15)–C(21) Fragment of Tedanolide C

    Science.gov (United States)

    Barth, Roland; Roush, William R.

    2010-01-01

    An enantioselective synthesis of α-methylene-β-hydroxy carboxylic acid derivatives via a highly diastereoselective, one-pot syn-aldol and β-elimination sequence utilizing the chiral β-(phenylselenyl)propionyl imide 15 is described. This new method, which constitutes an alternative to the Baylis-Hillman reaction, has been applied to the synthesis of the C(15)-C(21) fragment of tedanolide C. PMID:20405855

  5. Effect of the coverage level of carboxylic acids as a modifier for barium titanate nanoparticles on the performance of poly(vinylidene fluoride)-based nanocomposites for energy storage applications.

    Science.gov (United States)

    Niu, Yujuan; Xiang, Feng; Wang, Yifei; Chen, Jie; Wang, Hong

    2018-02-28

    Surface modification on nanoparticle fillers with organic groups is important to improve the performance of ceramic/polymer nanocomposites. Due to the small coverage level of carboxylic acids on the nanoparticle surface, studies on the use of carboxylic acids as a surface modifier for ceramic nanoparticles have been rarely reported. However, there is no study that proves that a small amount of modifier on the surface of nanoparticles cannot adequately improve the dispersion as well as the compatibility of nanoparticles with the matrix. Herein, we used three carboxylic acids to treat the surface of BaTiO 3 (BT) nanoparticles and adjusted the coverage level of the modifiers on the surface of BT nanoparticles through different ways. The nanocomposite films synthesized from the modified BT nanoparticles dispersed in the poly(vinylidene fluoride) (PVDF) polymer matrix were analyzed by dielectric spectroscopy, breakdown strength, leakage currents, and D-E loop measurements. The results show that the molecule dipole moment and polarizability of the modifier greatly influence the permittivity of the nanocomposites as the surface coverage level of the modifiers increases. Due to many influential factors, changes in the breakdown strength of the nanocomposites show diversity for three modifiers as the modifier content increases. For the nanocomposites applied in energy storage, the optimal content of the modifier on the surface of the nanoparticles needs to be determined by combining various properties of the nanocomposites.

  6. Thermochemistry of 2,2,5,7,8-pentamethylchroman-6-ol (PMC) and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox)

    International Nuclear Information System (INIS)

    Bernardes, Carlos E.S.; Simões, Ricardo G.; Diogo, Hermínio P.; Minas da Piedade, Manuel E.

    2014-01-01

    Highlights: • We measured C p,m o (cr/g), Δ f H m o (cr/g), Δ fus H m o and Δ sub H m o for 2,2,5,7,8-pentamethylchroman-6-ol (PMC). • We measured C p,m o (cr/g), Δ f H m o (cr/g), Δ fus H m o and Δ sub H m o for 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox). • We found that, if present, an intramolecular hydrogen bond in trolox must be weak. • We found that the replacement of a CH 3 group in PMC by a COOH group in trolox approximately conforms to group additivity. - Abstract: 2,2,5,7,8-Pentamethylchroman-6-ol (PMC, CAS number 950-99-2) and 6-hydroxy-2,5,7,8-tetramethyl chroman-2-carboxylic acid (trolox, CAS number 53188-07-1) are perhaps the two most widely used model compounds for α-tocoferol, the main active antioxidant form of vitamin E. Because the antioxidant activity of α-tocoferol, and of phenol derivatives (ArOH) in general (such as PMC and trolox), is intimately related to the breaking of the ArO-H bond, considerable efforts have been made to investigate how the energetics of that bond is linked to the structure and energetics of both the ArO · radical and the ArOH parent compound, which are reflected by the corresponding enthalpies of formation. In this work the standard molar enthalpies of formation of crystalline PMC (triclinic, space group P1 ¯ phase) and trolox (monoclinic, space group P2 1 /c phase), at T = 298.15 K, were obtained as Δ f H m o (PMC,cr) = −(513.7 ± 3.4) kJ · mol −1 and Δ f H m o (trolox,crI) = −(892.5 ± 4.1) kJ · mol −1 by combustion calorimetry. The results of drop-sublimation Calvet microcalorimetry experiments and vapor pressure vs. temperature measurements by the Knudsen effusion method, combined with C p,m o (cr) and C p,m o (g) data obtained by differential scanning calorimetry and calculated at the B3LYP/6-31+G(d, p) level of theory, respectively, led to Δ sub H m o (PMC) = (107.4 ± 0.8) kJ · mol −1 and Δ sub H m o (trolox) = (136.9 ± 2.5) kJ · mol −1 at T = 298.15 K

  7. Microwave-assisted synthesis, structural characterization, DFT studies, antibacterial and antioxidant activity of 2-methyl-4-oxo-1,2,3,4-tetrahydroquinazoline-2-carboxylic acid

    Science.gov (United States)

    Obafemi, Craig A.; Fadare, Olatomide A.; Jasinski, Jerry P.; Millikan, Sean P.; Obuotor, Efere M.; Iwalewa, Ezekiel O.; Famuyiwa, Samson O.; Sanusi, Kayode; Yilmaz, Yusuf; Ceylan, Ümit

    2018-03-01

    In the present study a new tetrahydroquinazoline-2-carboxylic, C10H10N2O3, 1‧, was synthesized and its structure was characterized by elemental analysis, IR, 1H NMR, 13C NMR data and high-resolution mass spectrometry. The spectral results are in line with the proposed structure. Single crystal X-ray structural analysis of the compound showed that the crystal structure adopts a monoclinic space group P21/c, with the packing of the molecule stabilized by Cdbnd O … …Hsbnd O, Nsbnd H … ….Odbnd Csbnd Osbnd intermolecular hydrogen bonding. The theoretical geometrical parameters of the compound have been calculated using density functional (DFT) and time-dependent density functional (TD-DFT) theory methods and have been used to predict the thermodynamic one-electron redox potential and the electronic absorption property of the compound. The theoretical characterization matched the experimental measurements, showing a good correlation. The calculated HOMO-LUMO gap (4.79 eV) suggests that compound 1‧ could be a potential antioxidant. The synthesized compound was screened for its in vitro antimicrobial activity against selected bacterial strains and antioxidant activity using the TAC, FRAP, NO and ABTS models. In vitro antioxidant activity of 1' showed a moderate activity, but weaker scavenging activity than the standards of ascorbic acid and trolox. Results of the antibacterial activity of the tested compound showed that it possesses a higher activity against Bacillus anthracis, Bacillus cereus, Bacillus polymyxa, Bacillus subtilis and Staphylococcus aureus than the two standard drugs, streptomycin and tetracycline, and better activity than tetracycline against Escherichia coli.

  8. A Ser/Thr protein kinase phosphorylates MA-ACS1 (Musa acuminata 1-aminocyclopropane-1-carboxylic acid synthase 1) during banana fruit ripening.

    Science.gov (United States)

    Choudhury, Swarup Roy; Roy, Sujit; Sengupta, Dibyendu N

    2012-08-01

    1-Aminocyclopropane-1-carboxylic acid synthase (ACS) catalyzes the rate-limiting step in ethylene biosynthesis during ripening. ACS isozymes are regulated both transcriptionally and post-translationally. However, in banana, an important climacteric fruit, little is known about post-translational regulation of ACS. Here, we report the post-translational modification of MA-ACS1 (Musa acuminata ACS1), a ripening inducible isozyme in the ACS family, which plays a key role in ethylene biosynthesis during banana fruit ripening. Immunoprecipitation analyses of phospholabeled protein extracts from banana fruit using affinity-purified anti-MA-ACS1 antibody have revealed phosphorylation of MA-ACS1, particularly in ripe fruit tissue. We have identified the induction of a 41-kDa protein kinase activity in pulp at the onset of ripening. The 41-kDa protein kinase has been identified as a putative protein kinase by MALDI-TOF/MS analysis. Biochemical analyses using partially purified protein kinase fraction from banana fruit have identified the protein kinase as a Ser/Thr family of protein kinase and its possible involvement in MA-ACS1 phosphorylation during ripening. In vitro phosphorylation analyses using synthetic peptides and site-directed mutagenized recombinant MA-ACS1 have revealed that serine 476 and 479 residues at the C-terminal region of MA-ACS1 are phosphorylated. Overall, this study provides important novel evidence for in vivo phosphorylation of MA-ACS1 at the molecular level as a possible mechanism of post-translational regulation of this key regulatory protein in ethylene signaling pathway in banana fruit during ripening.

  9. Post-ischemic administration of 5-methoxyindole-2-carboxylic acid at the onset of reperfusion affords neuroprotection against stroke injury by preserving mitochondrial function and attenuating oxidative stress.

    Science.gov (United States)

    Wu, Jinzi; Jin, Zhen; Yang, Xiaorong; Yan, Liang-Jun

    2018-02-26

    We previously reported that 5-methoxyindole-2-carboxylic acid (MICA) could induce preconditioning effect in the ischemic brain of rat. In the present study, we addressed the question of whether MICA could also trigger a postconditioning effect in ischemic stroke. To this end, MICA (100 mg/kg body weight) was injected intraperitoneally at the onset of 24 h reperfusion following 1 h ischemia in rat brain. Results indicate that stroked animals treated with MICA showed less brain infarction volume than that of vehicle-treated animals. Further experiments revealed that brain mitochondrial complexes I and IV showed elevated enzymatic activities in MICA treated group and the elevation in complex I activity was likely contributed by seemingly enhanced expression of many complex I subunits, which was determined by mass spectral peptide sequencing. When compared with vehicle-treated rats, the preservation of complexes I and IV activities was shown to be accompanied by enhanced mitochondrial membrane potential, increased ATP production, and decreased caspase-3 activity. Additional studies also indicate the involvement of NQO1 upregulation by the Nrf2 signaling pathway in this MICA postconditioning paradigm. Consequently, attenuated oxidative stress in the MICA treated group reflected by decrease in H 2 O 2 production and protein carbonylation and lipid peroxidation was detected. Taken together, the present study demonstrates that MICA can also induce a postconditioning effect in the ischemic brain of rat and the underlying mechanism likely involves preservation of mitochondrial function, upregulation of cellular antioxidative capacity, and attenuation of oxidative stress. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid as linker for Co(II)/Ni(II)/Cu(II) coordination polymers: Synthesis, structures and properties

    Science.gov (United States)

    Wang, Duo-Zhi; Wang, Xin-Fang; Du, Jia-Qiang; Dong, Jun-Liang; Xie, Fei

    2018-02-01

    We report the synthesis and characterization of five transition metal coordination polymers (CPs) based on M(II) (M: Co, Ni and Cu), 2-(hydroxymethyl)-1H-benzo[d]imidazole-5-carboxylic acid (H2L) ligand. They are formulated as {[Co2(HL)2(H2O)3(SO4)]·H2O}n (1), {[Co2(HL)2(H2O)2]·SiF6}n (2), {[Ni2(HL)2(H2O)3(SO4)]·2H2O}n (3), {[Ni2(HL)2(H2O)4]·H2O·SiF6}n (4), {[Cu2(HL)2(H2O)2]·SiF6}n (5). The complexes 1-5 structure were characterized by single-crystal X-ray diffraction, elemental analyses, infrared spectroscopy (IR), powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Complexes 1-5 are two-dimensional (2D) network type coordination polymers that 1-3, 5 crystallize in monoclinic system within the centrosymmetric space group P2(1)/c, and 4 in triclinic system P-1 space group, they show the same coordination modes (κ1-κ1)-(κ1)-(κ1)-μ3 in coordination polymers. Complexes 1 and 3 expand to three-dimensional framework by means of hydrogen bond interactions, and can be rationalized to be three-connected {63} topological network, while 2, 4, 5 exhibit the topological network with a four-connected {44·62} topological sql network. The luminescent properties (for complexes 1, 2) and UV diffuse reflectance (for complexes 1-5) in the solid state at room temperature were also investigated and discussed. Complexes 1-5 act as effective heterogeneous catalysts, under mild conditions, for the homocoupling reaction of 4-substituted aryl iodides bearing electron-donating groups (-CH3, -OCH3).

  11. 1-Aminocyclopropane-1-carboxylic acid (ACC) concentration and ACC synthase expression in soybean roots, root tips, and soybean cyst nematode (Heterodera glycines)-infected roots.

    Science.gov (United States)

    Tucker, Mark L; Xue, Ping; Yang, Ronghui

    2010-01-01

    Colonization of plant roots by root knot and cyst nematodes requires a functional ethylene response pathway. However, ethylene plays many roles in root development and whether its role in nematode colonization is direct or indirect, for example lateral root initiation or root hair growth, is not known. The temporal requirement for ethylene and localized synthesis of ethylene during the life span of soybean cyst nematode (SCN) on soybean roots was further investigated. Although a significant increase in ethylene evolution was not detected from SCN-colonized roots, the concentration of the immediate precursor to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), was higher in SCN-colonized root pieces and root tips than in other parts of the root. Moreover, expression analysis of 17 ACC synthase (ACS) genes indicated that a select set of ACS genes is expressed in SCN-colonized root pieces that is clearly different from the set of genes expressed in non-colonized roots or root tips. Semi-quantitative real-time PCR indicated that ACS transcript accumulation correlates with the high concentration of ACC in root tips. In addition, an ACS-like sequence was found in the public SCN nucleotide database. Acquisition of a full-length sequence for this mRNA (accession GQ389647) and alignment with transcripts for other well-characterized ACS proteins indicated that the nematode sequence is missing a key element required for ACS activity and therefore probably is not a functional ACS. Moreover, no significant amount of ACC was found in any growth stage of SCN that was tested.

  12. Formulation of mefenamic acid loaded transfersomal gel by thin film hydration technique and hand shaking method

    Directory of Open Access Journals (Sweden)

    Krishna Sailaja

    2017-04-01

    Full Text Available Objective(s: The aim of present study is to formulate mefenamic acid transdermal gel based on vesicular drug delivery approaches.Materials and Methods: For the preparation of mefenamic acid transdermal gel, transfersomes were selected as colloidal carriers. Transfersomes were prepared by hand shaking and thin film hydration techniques. The obtained transfersomes were characterized for vesicular diameter, zeta potential, drug content, entrapment efficiency and in vitro diffusion studies.Results: Among Different formulations of transfersomes, T10(prepared by thin film hydration and containing soya lecithin: span60 ratio 1:2 was considered as the best formulation because of its mean vesicular diameter of 369 nm, zeta potential of -14 mV, drug content of 99.6%, entrapment efficiency of 84.4%, and sustained drug release of 93.3% after 12 h.T10 formulation was incorporated into gel. Comparative study was made among plain gel, and transfersomal gel. Among these two gels, transfersomal gel considered as best because of its highest drug content (91%, spreadability (43.5 g.cm/sec, pH (6.9 and sustained drug release profile for 12 h.Conclusion: By comparing  hand shaking and thin film hydration techniques, it was found thin film hydration technique produced better results and transfersomal gel was indicated better results than plain gel.

  13. Vibrational tug-of-war: The pKA dependence of the broad vibrational features of strongly hydrogen-bonded carboxylic acids

    Science.gov (United States)

    Van Hoozen, Brian L.; Petersen, Poul B.

    2018-04-01

    Medium and strong hydrogen bonds give rise to broad vibrational features frequently spanning several hundred wavenumbers and oftentimes exhibiting unusual substructures. These broad vibrational features can be modeled from first principles, in a reduced dimensional calculation, that adiabatically separates low-frequency modes, which modulate the hydrogen bond length, from high-frequency OH stretch and bend modes that contribute to the vibrational structure. Previously this method was used to investigate the origin of an unusual vibrational feature frequently found in the spectra of dimers between carboxylic acids and nitrogen-containing aromatic bases that spans over 900 cm-1 and contains two broad peaks. It was found that the width of this feature largely originates from low-frequency modes modulating the hydrogen bond length and that the structure results from Fermi resonance interactions. In this report, we examine how these features change with the relative acid and base strength of the components as reflected by their aqueous pKA values. Dimers with large pKA differences are found to have features that can extend to frequencies below 1000 cm-1. The relationships between mean OH/NH frequency, aqueous pKA, and O-N distance are examined in order to obtain a more rigorous understanding of the origin and shape of the vibrational features. The mean OH/NH frequencies are found to correlate well with O-N distances. The lowest OH stretch frequencies are found in dimer geometries with O-N distances between 2.5 and 2.6 Å. At larger O-N distances, the hydrogen bonding interaction is not as strong, resulting in higher OH stretch frequencies. When the O-N distance is smaller than 2.5 Å, the limited space between the O and N determines the OH stretch frequency, which gives rise to frequencies that decrease with O-N distances. These two effects place a lower limit on the OH stretch frequency which is calculated to be near 700 cm-1. Understanding how the vibrational features

  14. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Xiangcong Wang

    2017-01-01

    Full Text Available Indole-2-carboxylic acid copper complex (ICA-Cu was successfully prepared and characterized through elemental analysis, IR, UV-Vis, 1H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu2(C9H6O2N4(H2O2]·2H2O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant KSV value was 3.99 × 104 M−1. The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na+ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH assay, a hydroxyl radical (OH scavenging assay, and a 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM, followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively. The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell lines. Also

  15. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II) Complexes.

    Science.gov (United States)

    Wang, Xiangcong; Yan, Maocai; Wang, Qibao; Wang, Huannan; Wang, Zhengyang; Zhao, Jiayi; Li, Jing; Zhang, Zhen

    2017-01-20

    Indole-2-carboxylic acid copper complex (ICA-Cu) was successfully prepared and characterized through elemental analysis, IR, UV-Vis, ¹H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu₂(C₉H₆O₂N)₄(H₂O)₂]·2H₂O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA) was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB) from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant K SV value was 3.99 × 10⁴ M -1 . The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na⁺ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, a hydroxyl radical (OH) scavenging assay, and a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM), followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively). The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT) assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell

  16. Scalable and chromatography-free synthesis of 2-(2-formylalkyl) arenecarboxylic acid derivatives through the supramolecularly controlled hydroformylation of vinylarene-2-carboxylic acids

    NARCIS (Netherlands)

    Dydio, P.; Reek, J.N.H.

    2014-01-01

    This protocol describes how to prepare 2-(2-formylalkyl)-arenecarboxylic acid derivatives, common building blocks for the synthesis of various valuable chemicals (e.g., anti-obesity and Alzheimer's disease treatment pharmaceuticals), by using the fully regioselective hydroformylation of vinyl arene

  17. Solvent and H/D isotope effects on the proton transfer pathways in heteroconjugated hydrogen-bonded phenol-carboxylic acid anions observed by combined UV-vis and NMR spectroscopy.

    Science.gov (United States)

    Koeppe, Benjamin; Guo, Jing; Tolstoy, Peter M; Denisov, Gleb S; Limbach, Hans-Heinrich

    2013-05-22

    Heteroconjugated hydrogen-bonded anions A···H···X(-) of phenols (AH) and carboxylic/inorganic acids (HX) dissolved in CD2Cl2 and CDF3/CDF2Cl have been studied by combined low-temperature UV-vis and (1)H/(13)C NMR spectroscopy (UVNMR). The systems constitute small molecular models of hydrogen-bonded cofactors in proteins such as the photoactive yellow protein (PYP). Thus, the phenols studied include the PYP cofactor 4-hydroxycinnamic acid methyl thioester, and the more acidic 4-nitrophenol and 2-chloro-4-nitrophenol which mimic electronically excited cofactor states. It is shown that the (13)C chemical shifts of the phenolic residues of A···H···X(-), referenced to the corresponding values of A···H···A(-), constitute excellent probes for the average proton positions. These shifts correlate with those of the H-bonded protons, as well as with the H/D isotope effects on the (13)C chemical shifts. A combined analysis of UV-vis and NMR data was employed to elucidate the proton transfer pathways in a qualitative way. Dual absorption bands of the phenolic moiety indicate a double-well situation for the shortest OHO hydrogen bonds studied. Surprisingly, when the solvent polarity is low the carboxylates are protonated whereas the proton shifts toward the phenolic oxygens when the polarity is increased. This finding indicates that because of stronger ion-dipole interactions small anions are stabilized at high solvent polarity and large anions exhibiting delocalized charges at low solvent polarities. It also explains the large acidity difference of phenols and carboxylic acids in water, and the observation that this difference is strongly reduced in the interior of proteins when both partners form mutual hydrogen bonds.

  18. Synthesis and Molecular Structures of the Lowest Melting Odd- and Even-Numbered α,β-Unsaturated Carboxylic Acids—(E-Hept-2-Enoic Acid and (E-Oct-2-Enoic Acid

    Directory of Open Access Journals (Sweden)

    Marcel Sonneck

    2016-06-01

    Full Text Available The molecular structures of the two lowest melting odd- and even-numbered α,β-unsaturated carboxylic acids—(E-hept-2-enoic acid (C7 and (E-oct-2-enoic acid (C8—are herein reported. The title compounds were crystallized by slow evaporation of ethanolic solutions at −30 °C. C7 crystallizes in the triclinic space group P 1 ¯ with two molecules in the unit cell and C8 in the monoclinic space group C2/c with eight molecules in the unit cell. The unit cell parameters for C7 are: a = 5.3049(2 Å, b = 6.6322(3 Å, c = 11.1428(5 Å, α = 103.972(3°, β = 97.542(3°, γ = 90.104(3°, and V = 376.92(3 Å3 (T = 150(2 K. The unit cell parameters for C8 are: a = 19.032(10 Å, b = 9.368(5 Å, c = 11.520(6 Å, β = 123.033(11°, and V = 1721.80(16 Å3 (T = 200(2 K.

  19. Safety, Tolerability, and Pharmacokinetics of Single and Multiple Oral Doses of an Omega-3-Carboxylic Acid Formulation in Healthy Male Japanese Subjects: A Phase 1 Single-Blind, Randomized, Placebo-Controlled Trial.

    Science.gov (United States)

    Noda, Yoshinori; Nilsson, Catarina; Shimada, Hitoshi; Kim, Hyosung; Lundström, Torbjörn; Yajima, Toshitaka

    2018-02-01

    OM3-CA (omega-3-carboxylic acids) is a complex mixture of omega-3 carboxylic acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which is approved in the United States for the treatment of hypertriglyceridemia. As part of its clinical development in Japan, we performed a phase 1 study to investigate the safety, tolerability, and pharmacokinetics after single and multiple doses of OM3-CA in healthy male Japanese subjects. Eighteen Japanese subjects were allocated to receive 2 or 4 g/day OM3-CA, or placebo (n = 6 per group). In addition, 6 white subjects received 4 g/day OM3-CA. The primary objective was to determine the safety and tolerability of OM3-CA. Plasma concentrations of EPA and DHA were adjusted for baseline values for pharmacokinetic analysis. Overall, OM3-CA was well tolerated in healthy Japanese subjects. Two Japanese subjects in each group and 5 white subjects experienced adverse events (AEs). Alanine aminotransferase increase was the most common AE in Japanese subjects, also seen with placebo, and diarrhea was the most common AE in white subjects. The maximum plasma concentrations of EPA and DHA were observed 5-6 hours postdose. The pharmacokinetic profiles of EPA and DHA after administration of OM3-CA were comparable between Japanese and white subjects. © 2017, The American College of Clinical Pharmacology.

  20. Structural and thermodynamic study of rare earth(III) complexation by poly-hydroxylated carboxylic acids: synthesis of new extractants and outlook for the extraction of these cations; Etude structurale et thermodynamique de la complexation de lanthanides (III) par des acides carboxyliques polyhydroxyles: synthese de nouveaux extractants et perspectives pour l'extraction de ces cations

    Energy Technology Data Exchange (ETDEWEB)

    Aury, S

    2002-12-15

    The aim of this work is: to improve the knowledge on the binding sites of the poly-hydroxylated carboxylic acids with the trivalent lanthanide(III) ions by comparing them to gluconic acid (previously studied) and to molecules with different configuration and with a variable number of OH functions (threonic acid, glyceric acid, 2-hydroxy-butanoic acid, 3-hydroxy-butanoic acid). To find the best complexing agent among different acids (aldonic acids, aldaric acids, di-hydroxybenzoic acids) (determination of the set of complexes and their stability constants by potentiometry, NMR and UV-Visible spectroscopy). To synthesize hydrophobic monoamides from one lactone form of saccharic acid, to study their complexing power and their capacity to extract the trivalent lanthanide(III) ions. (author)