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Sample records for carboxylic acid loading

  1. 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...

  2. Complicated Composting: Persistent Pyridine Carboxylic Acid Herbicides

    OpenAIRE

    Reimer, Julie

    2013-01-01

    This paper reviews pyridine carboxylic acid herbicide impacts on compost. Pyridine carboxylic acid herbicides are not completely broken down during grass growth, harvest and drying of hay, in the digestive tract of livestock, or during composting. These herbicides are a popular choice for broadleaf weed control because of this persistence: they remain effective for months or years. Pyridine carboxylic acids are also more effective than the common herbicide 2, 4-dichlorophenoxyacetic acid and ...

  3. Understanding biocatalyst inhibition by carboxylic acids

    Directory of Open Access Journals (Sweden)

    Laura R Jarboe

    2013-09-01

    Full Text Available Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli and Saccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the impact that saturated, straight-chain carboxylic acids, such as hexanoic, octanoic, decanoic and lauric acids can have on E. coli and S. cerevisiae, with the goal of identifying metabolic engineering strategies to increase robustness. Key effects of these carboxylic acids include damage to the cell membrane and a decrease of the microbial internal pH. Certain changes in cell membrane properties, such as composition, fluidity, integrity and hydrophobicity, and intracellular pH are often associated with increased tolerance. The availability of appropriate exporters, such as Pdr12, can also increase tolerance. The effect on metabolic processes, such as maintaining appropriate respiratory function, regulation of Lrp activity and inhibition of production of key metabolites such as methionine, are also considered. Understanding the mechanisms of biocatalyst inhibition by these desirable products can aid in the engineering of robust strains with improved industrial performance.

  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. Metal extraction by amides of carboxylic acids

    International Nuclear Information System (INIS)

    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 C7-C9 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

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

    International Nuclear Information System (INIS)

    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, N2 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. Carboxylic acid-functionalized SBA-15 nanorods for gemcitabine delivery

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, Zohreh; Badiei, Alireza, E-mail: abadiei@khayam.ut.ac.ir [University of Tehran, School of Chemistry, College of Science (Iran, Islamic Republic of); Ziarani, Ghodsi Mohammadi [Alzahra University, Research Laboratory of Pharmaceutical (Iran, Islamic Republic of)

    2015-03-15

    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{sub 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.

  8. Selective esterification of non-conjugated carboxylic acids in the presence of conjugated or aromatic carboxylic acids over active carbon supported methanesulfonic acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Non-conjugated carboxylic acids are selectively esterified in good yields in the presence of conjugated or aromatic carboxylic acids by stirring over active carbon supported methanesulfonic acid in di-chloromethane at room temperature.

  9. Applications of Carboxylic Acid Reductases in Oleaginous Microbes

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-24

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    R.L. Ames

    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

  11. 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

  12. Carboxylation and Decarboxylation of Aluminum Oxide Nanoparticles Using Bifunctional Carboxylic Acids and Octylamine

    Directory of Open Access Journals (Sweden)

    Shirin Alexander

    2016-01-01

    Full Text Available The carboxylation of alumina nanoparticles (NPs, with bifunctional carboxylic acids, provides molecular anchors that are used for building more complexed structures via either physisorption or chemisorption. Colloidal suspensions of the NPs may be prepared by covalently bonding a series of carboxylic acids with secondary functional groups (HO2C-R-X to the surface of the NPs: lysine (X = NH2, p-hydroxybenzoic acid (X = OH, fumaric acid (X = CO2H, and 4-formylbenzoic acid (X = C(OH. Subsequent reaction with octylamine at either 25°C or 70°C was investigated. Fourier transform IR-attenuated reflectance spectroscopy (FTIR-ATR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM along with energy dispersive X-ray (EDX analysis were used to characterize the bifunctionalized monolayers and/or multilayer corona surrounding the alumina NPs and investigate the reaction mechanism of octylamine with the functional groups (X of the NPs. Except for the fumaric functionalized NPs, addition of octylamine to the functionalized NPs leads to removal of excess carboxylic acid corona from the surface via an amide formation. The extent of the multilayer is dependent on the strength of the acid⋯acid interaction.

  13. Kinetic and Thermodynamic Parameters for Uncatalyzed Esterification of Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Kehinde S. Bankole

    2014-06-01

    Full Text Available A fundamental study on uncatalyzed esterification of various biomass-derived aliphatic carboxylic acids with stoichiometric amount of ethanol has been investigated in an isothermal batch reactor, with the objective to convert carboxylic acids to corresponding ethyl esters and to determine both the kinetic and thermodynamic parameters. The effects of temperature on the conversion of carboxylic acid, kinetic and thermodynamic parameters have been investigated. Temperature was found to have significant effect on the rate of reaction and conversion of carboxylic acid. A simple second order reversible kinetic model was developed to determine the kinetic and thermodynamic parameters. The thermodynamic and kinetic parameters varied for uncatalyzed esterification reaction of both short-chain and long-chain carboxylic acids considered. The predicted data from the kinetic model were correlated with experimental data and the two sets of data agreed reasonably well for the uncatalyzed esterification systems. It was observed that the Van’t Hoff plot for uncatalyzed esterification of linoleic acid was non-linear curve, whereas for the Arrhenius and Eyring plots, they were linear. Additional experiments to assess the catalytic and corrosion effects of several metallic substances revealed Inconel 625 alloy, nickel wire and stainless steel materials were susceptible to corrosion problem with uncatalyzed esterification reaction at elevated reaction temperatures. However, tantalum and grade-5 titanium materials were corrosion resistance metals, suitable for similar reaction conditions and this can encourage the design of a flow reactor system. Although, uncatalyzed esterification of carboxylic acids at elevated reaction temperature is still at laboratory scale. It is our hope that the estimated kinetic and thermodynamic parameters would be the guiding tools for reactor scale-up, thus providing a new perspective into the conversion of biomass-derived carboxylic

  14. 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.

  15. Pyrazine Carboxylic Acid Derivatives of Dichlorobis(Cyclopentadienyltitanium(IV

    Directory of Open Access Journals (Sweden)

    Satish Chandra Dixit

    2012-07-01

    Full Text Available Reactions of dichlorobis(cyclopentadienyltitanium(IV with pyrazine carboxylic acids viz. 2-pyrazine carboxylic acid (2-PzCH, 5-methyl-2-pyrazine carboxylic acid (MPzCH and 2,3-pyrazine dicarboxylic acid (2,3-PzDCH2 were carried out in different stoichiometric ratios. Complexes of the type Cp2Ti(2-PzCCl , Cp2Ti(2-PzC2 ,Cp2Ti(MPzCCl,Cp2Ti(MPzC2, Cp2Ti(2,3-PzDCHCl and Cp2Ti(2,3-PzDCH2 were obtained. These newly synthesized complexes were characterized on the basis of elemental analyses, electrical conductance, magnetic moment and spectral data.

  16. Pyrazine Carboxylic Acid Derivatives of Dichlorobis(Cyclopentadienyl)titanium(IV)

    OpenAIRE

    Satish Chandra Dixit; Rohit Kumar Singh

    2012-01-01

    Reactions of dichlorobis(cyclopentadienyl)titanium(IV) with pyrazine carboxylic acids viz. 2-pyrazine carboxylic acid (2-PzCH), 5-methyl-2-pyrazine carboxylic acid (MPzCH) and 2,3-pyrazine dicarboxylic acid (2,3-PzDCH2) were carried out in different stoichiometric ratios. Complexes of the type Cp2Ti(2-PzC)Cl , Cp2Ti(2-PzC)2 ,Cp2Ti(MPzC)Cl,Cp2Ti(MPzC)2, Cp2Ti(2,3-PzDCH)Cl and Cp2Ti(2,3-PzDCH)2 were obtained. These newly synthesized complexes were characterized on the basis of elemental analyse...

  17. Conformation of some carboxylic acids and their derivatives

    NARCIS (Netherlands)

    Kanters, J.A.; Kroon, Jan; Peerdeman, A.F.; Schoone, J.C.

    1967-01-01

    The conformation in the crystalline state of some aliphatic carboxylic acids and their derivatives has been analysed. This analysis, based upon the results of structure determinations by means of X-ray diffraction, seems to support the concept that the conformation of a molecule is governed chiefly

  18. Synthon preferences in cocrystals of cis-carboxamides:carboxylic acids

    NARCIS (Netherlands)

    A.M. Moragues-Bartolome; W. Jones; A.J. Cruz-Cabeza

    2012-01-01

    We study synthon preferences in cocrystals of cis-carboxamides with carboxylic acids using a combination of database analyses, cocrystallisation experiments and theoretical calculations. We classify the cis-carboxamides into three families: primary amides, cyclic amides (lactams) and cyclic imides.

  19. Enhance decarboxylation reaction of carboxylic acids in clay minerals

    International Nuclear Information System (INIS)

    Clay minerals are important constituents of the Earth's crust. These minerals catalyze reactions in several ways: by energy transfer processes, redox reactions, stabilization of intermediates and by Broensted or Lewis acidity behavior. Important set of organic reactions can be improved in the precedence of clay minerals. Besides the properties of clays to catalyze chemical reactions, it is possible to enhance some of its reactions by using ionizing radiation. The phenomenon of radiation-induced catalysis may be connected with ionizing process in the solid and with the trapped non-equilibrium charge carriers. In this paper we are reporting the decarboxylation reaction of carboxylic acids catalyzed by clay and by irradiation of the system acid-clay. We studied the behaviour of several carboxylic acids and analyzed them by gas chromatography, X-ray and infrared spectroscopy. The results showed that decarboxylation of the target compound is the dominating pathway. The reaction is enhanced by gamma radiation in several orders of magnitude. (author)

  20. Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

    Science.gov (United States)

    Vaïtilingom, M.; Charbouillot, T.; Deguillaume, L.; Maisonobe, R.; Parazols, M.; Amato, P.; Sancelme, M.; Delort, A.-M.

    2011-02-01

    Clouds are multiphasic atmospheric systems in which the dissolved organic compounds, dominated by carboxylic acids, are subject to multiple chemical transformations in the aqueous phase. Among them, solar radiation, by generating hydroxyl radicals (•OH), is considered as the main catalyzer of the reactivity of organic species in clouds. We investigated to which extent the active biomass existing in cloud water represents an alternative route to the chemical reactivity of carboxylic acids. Pure cultures of seventeen bacterial strains (Arthrobacter, Bacillus, Clavibacter, Frigoribacterium, Pseudomonas, Sphingomonas and Rhodococcus), previously isolated from cloud water and representative of the viable community of clouds were first individually incubated in two artificial bulk cloud water solutions at 17 °C and 5 °C. These solutions mimicked the chemical composition of cloud water from "marine" and "continental" air masses, and contained the major carboxylic acids existing in the cloud water (i.e. acetate, formate, succinate and oxalate). The concentrations of these carboxylic compounds were monitored over time and biodegradation rates were determined. In average, they ranged from 2 ×10-19 for succinate to 1 × 10-18 mol cell-1 s-1 for formate at 17 °C and from 4 × 10-20 for succinate to 6 × 10-19 mol cell-1 s-1 for formate at 5 °C, with no significant difference between "marine" and "continental" media. In parallel, irradiation experiments were also conducted in these two artificial media to compare biodegradation and photodegradation of carboxylic compounds. To complete this comparison, the photodegradation rates of carboxylic acids by •OH radicals were calculated from literature data. Inferred estimations suggested a significant participation of microbes to the transformation of carboxylic acids in cloud water, particularly for acetate and succinate (up to 90%). Furthermore, a natural cloud water sample was incubated (including its indigenous microflora

  1. Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

    Directory of Open Access Journals (Sweden)

    M. Vaïtilingom

    2011-02-01

    Full Text Available Clouds are multiphasic atmospheric systems in which the dissolved organic compounds, dominated by carboxylic acids, are subject to multiple chemical transformations in the aqueous phase. Among them, solar radiation, by generating hydroxyl radicals (OH, is considered as the main catalyzer of the reactivity of organic species in clouds. We investigated to which extent the active biomass existing in cloud water represents an alternative route to the chemical reactivity of carboxylic acids. Pure cultures of seventeen bacterial strains (Arthrobacter, Bacillus, Clavibacter, Frigoribacterium, Pseudomonas, Sphingomonas and Rhodococcus, previously isolated from cloud water and representative of the viable community of clouds were first individually incubated in two artificial bulk cloud water solutions at 17 °C and 5 °C. These solutions mimicked the chemical composition of cloud water from "marine" and "continental" air masses, and contained the major carboxylic acids existing in the cloud water (i.e. acetate, formate, succinate and oxalate. The concentrations of these carboxylic compounds were monitored over time and biodegradation rates were determined. In average, they ranged from 2 ×10−19 for succinate to 1 × 10−18 mol cell−1 s−1 for formate at 17 °C and from 4 × 10−20 for succinate to 6 × 10−19 mol cell−1 s−1 for formate at 5 °C, with no significant difference between "marine" and "continental" media. In parallel, irradiation experiments were also conducted in these two artificial media to compare biodegradation and photodegradation of carboxylic compounds. To complete this comparison, the photodegradation rates of carboxylic acids by OH radicals were calculated from literature data. Inferred estimations suggested a significant participation of microbes to the transformation of carboxylic acids in cloud water

  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. Separation and determination of some carboxylic acids by capillary electrophoresis

    International Nuclear Information System (INIS)

    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)

  4. Amino Acids, Aromatic Compounds, and Carboxylic Acids: How Did They Get Their Common Names?

    Science.gov (United States)

    Leung, Sam H.

    2000-01-01

    Surveys the roots of the common names of organic compounds most likely to be encountered by undergraduate organic chemistry students. Includes information for 19 amino acids, 17 aromatic compounds, and 21 carboxylic acids. (WRM)

  5. 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, sprin......-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....

  6. 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.

  7. Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

    Indian Academy of Sciences (India)

    Aamer Saeed; Zaman Ashraf

    2006-09-01

    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 a pure state. This two-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.

  8. Biarylalkyl Carboxylic Acid Derivatives as Novel Antischistosomal Agents.

    Science.gov (United States)

    Mäder, Patrick; Blohm, Ariane S; Quack, Thomas; Lange-Grünweller, Kerstin; Grünweller, Arnold; Hartmann, Roland K; Grevelding, Christoph G; Schlitzer, Martin

    2016-07-01

    Parasitic platyhelminths are responsible for serious infectious diseases, such as schistosomiasis, which affect humans as well as animals across vast regions of the world. The drug arsenal available for the treatment of these diseases is limited; for example, praziquantel is the only drug currently used to treat ≥240 million people each year infected with Schistosoma spp., and there is justified concern about the emergence of drug resistance. In this study, we screened biarylalkyl carboxylic acid derivatives for their antischistosomal activity against S. mansoni. These compounds showed significant influence on egg production, pairing stability, and vitality. Tegumental lesions or gut dilatation was also observed. Substitution of the terminal phenyl residue in the biaryl scaffold with a 3-hydroxy moiety and derivatization of the terminal carboxylic acid scaffold with carboxamides yielded compounds that displayed significant antischistosomal activity at concentrations as low as 10 μm with satisfying cytotoxicity values. The present study provides detailed insight into the structure-activity relationships of biarylalkyl carboxylic acid derivatives and thereby paves the way for a new drug-hit moiety for fighting schistosomiasis. PMID:27159334

  9. Study on Copolymerization of Rare Earth-Carboxylic Acid Complex

    Institute of Scientific and Technical Information of China (English)

    Qiu Guanmin(邱关明); Zhang Ming(张明); Yan Chang hao(严长浩); Zhou Lanxiang(周兰香); Dai Shaojun(戴少俊); Okamo to Hiroshi

    2003-01-01

    Complex of rare earth with carboxylic acid was prepared by precipita tion and direct method. It was copolymerized with such monomers as acrylic acid and other ones to synthesize ionomer of rare earth and organic polymer with different rare earth contents. Its glass-transition temperature and heat stability were analyzed by TG and DTA. Infra-red detector was used to show its structure. The effect of rare earth complex prepared by different methods on copolymerization and properties of copolymers was also discussed.

  10. Azetidine-2-carboxylic acid in garden beets (Beta vulgaris).

    Science.gov (United States)

    Rubenstein, Edward; Zhou, Haihong; Krasinska, Karolina M; Chien, Allis; Becker, Christopher H

    2006-05-01

    Azetidine-2-carboxylic acid (L-Aze) is a toxic and teratogenic non-protein amino acid. In many species, including man, L-Aze is misincorporated into protein in place of proline, altering collagen, keratin, hemoglobin, and protein folding. In animal models of teratogenesis, it causes a wide range of malformations. The role of L-Aze in human disease has been unexplored, probably because the compound has not been associated with foods consumed by humans. Herein we report the presence of L-Aze in the garden or table beet (Beta vulgaris).

  11. Biohydrogen and carboxylic acids production from wheat straw hydrolysate.

    Science.gov (United States)

    Chandolias, Konstantinos; Pardaev, Sindor; Taherzadeh, Mohammad J

    2016-09-01

    Hydrolyzed wheat straw was converted into carboxylic acids and biohydrogen using digesting bacteria. The fermentations were carried out using both free and membrane-encased thermophilic bacteria (55°C) at various OLRs (4.42-17.95g COD/L.d), in semi-continuous conditions using one or two bioreactors in a series. The highest production of biohydrogen and acetic acid was achieved at an OLR of 4.42g COD/L.d, whilst the highest lactic acid production occurred at an OLR of 9.33g COD/L.d. Furthermore, the bioreactor with both free and membrane-encased cells produced 60% more lactic acid compared to the conventional, free-cell bioreactor. In addition, an increase of 121% and 100% in the production of acetic and isobutyric acid, respectively, was achieved in the 2nd-stage bioreactor compared to the 1st-stage bioreactor.

  12. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...... to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  13. Two Dimensional Polyamides Prepared From Unsaturated Carboxylic Acids And Amines.

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi Heng (East Lansing, MI); Wright, Stacy C. (Lansing, MI); Danzig, Morris (Northbrook, IL); Taylor, Andrew C. (Ann Arbor, MI)

    2002-07-17

    A polyamide and a process for preparing the polyamide are disclosed. The process comprises reacting in a reaction mixture a monomer selected from unsaturated carboxylic acids, esters of unsaturated carboxylic acids, anhydrides of unsaturated carboxylic acids, and mixtures thereof, and a first amine to form an intermediate reaction product in the reaction mixture, wherein the first amine is selected from RR.sub.1 NH, RNH.sub.2, RR.sub.1 NH.sub.2.sup.+, RNH.sub.3.sup.+ and mixtures thereof, wherein R and R.sub.1 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, and reacting the intermediate reaction product and a second amine to form a polyamide, wherein the second amine is selected from R.sub.2 R.sub.3 NH, R.sub.2 NH.sub.2, R.sub.2 R.sub.3 NH.sub.2.sup.+, R.sub.2 NH.sub.3.sup.+ and mixtures thereof wherein R.sub.2 and R.sub.3 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, wherein multiple of the R, R.sub.1, R.sub.2, and R.sub.3 are in vertically aligned spaced relationship along a backbone formed by the polyamide. In one version of the invention, the monomer is selected from maleic anhydride, maleic acid esters, and mixtures thereof. In another version of the invention, the first amine is an alkylamine, such as tetradecylamine, and the second amine is a polyalkylene polyamine, such as pentaethylenehexamine. In yet another version of the invention, the first amine and the second amine are olefinic or acetylenic amines, such as the reaction products of an alkyldiamine and an acetylenic carboxylic acid. The first amine and the second amine may be the same or different depending on the desired polyamide polymer structure.

  14. 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.

  15. 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)

  16. Integrated process for preparing a carboxylic acid from an alkane

    Energy Technology Data Exchange (ETDEWEB)

    Benderly, Abraham (Elkins Park, PA); Chadda, Nitin (Radnor, PA); Sevon, Douglass (Fairless Hills, PA)

    2011-12-20

    The present invention relates to an integrated process for producing unsaturated carboxylic acids from the corresponding C.sub.2-C.sub.4 alkane. The process begins with performance of thermally integrated dehydrogenation reactions which convert a C.sub.2-C.sub.4 alkane to its corresponding C.sub.2-C.sub.4 alkene, and which involve exothermically converting a portion of an alkane to its corresponding alkene by oxidative dehydrogenation in an exothermic reaction zone, in the presence of oxygen and a suitable catalyst, and then feeding the products of the exothermic reaction zone to an endothermic reaction zone wherein at least a portion of the remaining unconverted alkane is endothermically dehydrogenated to form an additional quantity of the same corresponding alkene, in the presence of carbon dioxide and an other suitable catalyst. The alkene products of the thermally integrated dehydrogenation reactions are then provided to a catalytic vapor phase partial oxidation process for conversion of the alkene to the corresponding unsaturated carboxylic acid or nitrile. Unreacted alkene and carbon dioxide are recovered from the oxidation product stream and recycled back to the thermally integrated dehydrogenation reactions.

  17. Exploring the reductive capacity of Pyrococcus furiosus. The reduction of carboxylic acids and pyridine nucleotides

    OpenAIRE

    Ban, van den, A.W.

    2001-01-01

    This Ph.D. project started in 1997 and its main goal was to obtain insight in the reductive capacity of the hyperthermophilic archaeon Pyrococcus furiosus . The research was focused on the biocatalytic reduction of carboxylic acids.Reductions of carboxylic acids are interesting reactions, since the generated products, aldehydes and alcohols, are potentially applicable in the fine-chemical industry. However, the reduction of carboxylic acids to the corresponding aldehydes is a thermodynamicall...

  18. Carboxylic acid terminated, solution exfoliated graphite by organic acylation and its application in drug delivery

    Indian Academy of Sciences (India)

    KOUSHIK BHOWMIK; AMRITA CHAKRAVARTY; U MANJU; GOUTAM DE; ARNAB MUKHERJEE

    2016-09-01

    Graphite nanosheets are considered as a promising material for a range of applications from flexible electronics to functional nanodevices such as biosensors, intelligent coatings and drug delivery. Chemical functionalizationof graphite nanosheets with organic/inorganic materials offers an alternative approach to control the electronic properties of graphene, which is a zero band gap semiconductor in pristine form. In this paper, we report the aromatic electrophilic substitution of solution exfoliated graphite nanosheets (SEGn). The highly conjugated π-electronic system of graphite nanosheets enable it to have an amphiphilic characteristic in aromatic substitution reactions. The substitution was achieved through Friedel–Crafts (FC) acylation reaction under mild conditions using succinic anhydride as acylating agent and anhydrous aluminum chloride as Lewisacid. 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 spectroscopicand microscopic techniques. Highly stable water-dispersed sodium salt of carboxylic acid terminated graphite nanosheets (SEGn–FC-Na) was also prepared. A comparative sheet-resistance measurements of SEGn, SEGn–FC and SEGn–FC-Na were also done. Finally, the anticancer drug doxorubicin (DOX) was loaded on water dispersible SEGn–FC-Na with a loading capacity of 0.266 mg mg−1 of SEGn–FC-Na and the release of DOX from this water-soluble DOX-loaded SEGn–FC-Na at two different temperatures was found to be strongly pHdependent.

  19. Biogeochemistry of the stable carbon isotopes in carboxylic acids

    International Nuclear Information System (INIS)

    The carbon isotopic compositions of the carboxyl carbons of fatty acids were determined by measuring the isotopic composition of the carbon dioxide quantitatively released from the acid. A modified version of the Schmidt decarboxylation developed and tested in this work was employed. A study of the evolution of CO2 at 5 +- 20C from the Schmidt decarboxylation of octanoic acid during the developmental program revealed two kinetic phases, each characterized by different rate constants and carbon isotope effects. The first, slower reaction phase displayed overall first-order kinetics, its rate being independent of HN3 concentration. Both pre-equilibration of the HN3-CHCl3 decarboxylation reagent with H2SO4 and saturation of the catalytic H2SO4 phase with KHSO4 drastically altered the rate of evolution and isotopic composition of the product CO2. The mechanistic implications of these results were discussed. A review of the metabolism of saturated fatty acids was made in which the impact of potential isotope fractionations in the various chemical reactions comprising the biosynthetic pathways on the intramolecular carbon isotope distribution within fatty acids was discussed

  20. Spectrofluorimetric determination of gallium with calon-carboxylic acid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A simple and sensitive spectrofluorimetric procedure for the analysis of microquantities of gallium in alloy wasdescribed. The method is based on the formation of Ga(Ⅲ)-CCA (calon-carboxylic acid) complex. The emission of thefluorescent complex was measured at λ = 620 nm with excitation at λ = 584 nm. A good linearity was found in the galliumrange of 0.7-280 ng/mL. The precision of the method is good and the relative standard deviation is 1.9% for a gallium stan-dard solution of 70 ng/mL. The procedure was proved to be suitable in terms of accuracy and selectivity for the mi-croamount of gallium in alloy.

  1. A synthetic approach to carbon-14 labeled anti-bacterial naphthyridine and quinolone carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Ekhato, I.V.; Huang, C.C. (Parke, Davis and Co., Ann Arbor, MI (United States))

    1993-09-01

    Labeled versions of (S)-clinafloxacin (1) and two napththyridine carboxylic acid anti-bacterial compounds 2 and 3 which are currently in development were synthesized. Preparations started from hitherto unknown bromo compounds 22 and 10, from which the corresponding [sup 14]C-labeled aromatic carboxylic acids 23 and 12 were generated by metal-halogen exchange followed by carboxylation reaction. Details of these preparations are given. (author).

  2. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Science.gov (United States)

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. PMID:26572799

  3. Exploring the reductive capacity of Pyrococcus furiosus. The reduction of carboxylic acids and pyridine nucleotides

    NARCIS (Netherlands)

    Ban, van den E.C.D.

    2001-01-01

    This Ph.D. project started in 1997 and its main goal was to obtain insight in the reductive capacity of the hyperthermophilic archaeon Pyrococcus furiosus . The research was focused on the biocatalytic reduction of carboxylic acids.Reductions of carboxylic acids are interes

  4. 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...

  5. 40 CFR 721.10142 - Oxabicycloalkane carboxylic acid alkanediyl ester (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxabicycloalkane carboxylic acid alkanediyl ester (generic). 721.10142 Section 721.10142 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10142 Oxabicycloalkane carboxylic acid...

  6. 3-Methyl-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Rajendiran Nagappan

    2010-01-01

    Full Text Available 3-Methyl-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxylic acid was synthesized chemoselectively from 3-formyl-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxylic acid, using Et3SiH/I2 as a reducing agent. The title compound was characterized by IR, 1H NMR, 13C NMR and LCMS.

  7. Thermochemistry of aqueous pyridine-3-carboxylic acid (nicotinic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Elsa M. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto Politecnico de Setubal, ESTBarreiro, Rua Americo da Silva Marinho, 2839-001 Lavradio (Portugal); Rego, Talita S. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Minas da Piedade, Manuel E., E-mail: memp@fc.ul.p [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2011-06-15

    Research highlights: {yields} We determined the {Delta}{sub sol}H{sub m} of solid nicotinic acid (NA) in water by solution calorimetry. {yields} We determined {Delta}{sub dil}H{sub m} of an aqueous nicotinic acid solution by flow calorimetry. {yields} We determined (aq, {infinity}) for the 3 NA species involved in acid/base equilibria. {yields} We determined the enthalpy of formation of NA(aq) under saturation conditions.. - Abstract: The molar enthalpy of solution of solid nicotinic acid (NA) at T = 298.15 K, to give an aqueous solution of molality m = 3.748 . 10{sup -3} mol {center_dot} kg{sup -1}, was determined as {Delta}{sub sol}H{sub m} = (19,927 {+-} 48) J {center_dot} mol{sup -1}, by solution calorimetry. Enthalpies of dilution, {Delta}{sub dil}H{sub m}, of 0.1005 mol {center_dot} kg{sup -1} aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09) mol {center_dot} kg{sup -1} were also measured by flow calorimetry. Combining the two sets of data and the results of pH measurements, with values of proton dissociation enthalpies and {Delta}{sub f}H{sub m}{sup 0}(NA, cr) selected from the literature, it was possible to derive the standard molar enthalpies of formation of the three nicotinic acid species involved in protonation/deprotonation equilibria, at infinite dilution: {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COOH.{infinity}H{sub 2}O,aq) = (328.2 {+-} 1.2) kJ {center_dot} mol{sup -1}, {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (325.0 {+-} 1.2) kJ {center_dot} mol{sup -1}, and {Delta}{sub f}H{sub m}{sup 0}(NC{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (313.7 {+-} 1.2) kJ {center_dot} mol{sup -1}. Finally, the enthalpy of solution of nicotinic acid at T = 298.15 K, under saturation conditions (m = 0.138 mol {center_dot} kg{sup -1}), and the standard molar enthalpy of formation of the corresponding solution could also be obtained as {Delta

  8. A novel synthesis of carbon-labelled quinolone-3-carboxylic acid antibacterials

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.M.; Sutherland, D.R. (Glaxo Research and Development Ltd., Greenford (United Kingdom). Isotope Chemistry Group)

    1994-10-01

    3-Iodoquinolones were prepared from the corresponding quinolone-3-carboxylic acids by Hunsdiecker-type iododecarboxylation reactions with lead tetraacetate and iodine. Cyanation of the iodo compounds with mixtures of potassium [[sup 13]C]cyanide and copper (1) iodide, gave [3-[sup 13]C]cyanoquinolones which on acidic hydrolysis afforded quinolone-[3-[sup 13]C]carboxylic acids. In this way, nalidixic acid, an immediate precursor of norfloxacin, and quinolone WIN57273 were labelled with carbon-13 in the metabolically stable carboxylic acid fragment. (author).

  9. Efficient Debromination of Vicinal (, (-Dibromo Carboxylic Acid Derivatives with the Sm/HOAc System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The α, β vicinal dibromo carboxylic acid and its derivatives were debrominated with Sm/HOAc system to afford the corresponding cinnamic acid and its derivatives in good yields under mild conditions.

  10. 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.

  11. 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.

  12. Influence of cyclic dimer formation on the phase behavior of carboxylic acids.

    Science.gov (United States)

    Janecek, Jiri; Paricaud, Patrice

    2012-07-12

    A new thermodynamic approach based on the Sear and Jackson association theory for doubly bonded dimers [Mol. Phys.1994, 82, 1033] is proposed to describe the thermodynamic properties of carboxylic acids. The new model is able to simultaneously represent the vapor pressures, saturated densities, and vaporization enthalpies of the shortest acids and is in a much better agreement with experimental data than other approaches that do no consider the formation of cyclic dimers. The new model is applied to mixtures of carboxylic acids with nonassociating compounds, and a very good description of the vapor-liquid equilibria in mixtures of alkanes + carboxylic acids is obtained.

  13. Keto-Enol Tautomerizations Catalyzed by Water and Carboxylic Acids

    Science.gov (United States)

    da Silva, G.

    2009-12-01

    The ability of weakly-bound complexes to influence the kinetics of gas phase reactions, particularly in atmospheric chemistry, has long been speculated. This study uses quantum chemistry and statistical reaction rate theory to identify that bound water molecules can significantly reduce barriers to intramolecular hydrogen shift reactions, via a double-hydrogen-shift mechanism. The bound water molecule directly participates in the hydrogen shift reaction, exchanging a H atom with its counterpart. For the vinyl alcohol to acetaldehyde keto-enol tautomerization this mechanism cuts the reaction barrier approximately in half, reducing it by over 30 kcal mol-1. In contrast, while a non-participatory ‘bystander’ water molecule also reduces the hydrogen shift barrier, it is only by around 3 kcal/mol. When a carboxylic acid replaces water in the double-hydrogen-shift mechanism the barrier to keto-enol tautomerization is decimated, reduced to less than 6 kcal/mol (around 15 kcal/mol in the reverse direction). This results from reduced strain in the hydrogen shift transition state, and achieves enol lifetimes in the troposphere that become short on relevant timescales. Rapid enol to ketone isomerizations are currently required to explain the oxidation products of isoprene. The wider significance of rapid hydrogen shift reactions in atmospherically relevant molecules and radicals is also explored.

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

    International Nuclear Information System (INIS)

    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

  15. The investigation of the reactions of some pyrazole-3-carboxylic acids with various diamines and diols

    OpenAIRE

    Rahmi Kasımoğulları; Makbule Maden; Samet Mert

    2012-01-01

    In this study, some new derivatives were synthesized of 4-benzoyl-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid (1) and 4-(ethoxycarbonyl)-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid (2) that they were pyrazole carboxylic acid derivatives. Firstly, 1 and 2 reacted with SOCl2 to transform them into acyl chlorides (3, 4). Then various bis-carboxamide derivatives (58) were obtained from the reaction of 3 and 4 with various diamines and also a ;#946;-hydroxy ester (9) deri...

  16. The investigation of the reactions of some pyrazole-3-carboxylic acids with various diamines and diols

    OpenAIRE

    Kasımoğulları, Rahmi; Maden, Makbule; Mert, Samet

    2012-01-01

    In this study, some new derivatives were synthesized of 4-benzoyl-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid (1) and 4-(ethoxycarbonyl)-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid (2) that they were pyrazole carboxylic acid derivatives. Firstly, 1 and 2 reacted with SOCl2 to transform them into acyl chlorides (3, 4). Then various bis-carboxamide derivatives (5–8) were obtained from the reaction of 3 and 4 with various diamines and also a β-hydroxy ester (9)...

  17. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  18. 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, L.J.; King, C.J.

    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. CO{sub 2} and H{sub 2}S) 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 concentration

  19. Cyclic Comonomers for the Synthesis of Carboxylic Acid and Amine Functionalized Poly(l-Lactic Acid

    Directory of Open Access Journals (Sweden)

    Markus Heiny

    2015-03-01

    Full Text Available Degradable aliphatic polyesters such as poly(lactic acid are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional α-ω epoxyesters as comonomers for lactide polymerization. Salient features of these highly functionalized epoxides are versatility in functionality and a short synthetic route of less than four steps. The α-ω epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  20. Efficient Fixation of Carbon Dioxide by Electrolysis - Facile Synthesis of Useful Carboxylic Acids -

    Institute of Scientific and Technical Information of China (English)

    Masao Tokuda

    2006-01-01

    Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide (scCO2) has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.

  1. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    Science.gov (United States)

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass.

  2. Palladium-Catalyzed C–C Bond Formations via Activation of Carboxylic Acids and Their Derivatives

    OpenAIRE

    Song, Bingrui

    2013-01-01

    Applications of carboxylic acids and their derivatives in transition metal-catalyzed cross-coupling reactions regio-selectively forming Csp3-Csp2, and Csp2-Csp2 bonds were explored in this thesis. Several important organic building blocks such as aryl acetates, diaryl acetates, imines, ketones, biaryls, styrenes and polysubstituted alkenes were successfully accessed from carboxylic acids and their derivatives by the means of C–H activation and decarboxylative cross-couplings. An efficient ...

  3. Gamma-aminoadamantane carboxylic acids : orientating building blocks in peptide chemistry

    OpenAIRE

    Wanka, Lukas

    2007-01-01

    The present thesis deals with gamma-aminoadamantane carboxylic acids. Allthough the simplest of these structural analogues of GABA were known for decades, no significant peptide chemistry has been disclosed. Therefore, improved syntheses of these compounds were worked out that allowed for facilitated syntheses of already known as well as new members of gamma-aminoadamantane carboxylic acids. Fmoc-/tert. butyl protective group chemistry was utilized to synthesize peptides incorporating the gam...

  4. Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

    Directory of Open Access Journals (Sweden)

    Brett N. Hemric

    2016-01-01

    Full Text Available This paper reports a novel approach for the direct and facile synthesis of 1,2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O-benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates.

  5. Application of IBX Method for the Synthesis of Ketones from Carboxylic Acids

    OpenAIRE

    KARABULUT, H. R. Ferhat; KAÇAN, Mesut

    2003-01-01

    Methoxy phenyl propionic acid and some derivatives are converted to ketones using a new method. All classical methods to obtain ketones from carboxylic acids via acid halide consistently gave very low yields and regularly generated intermolecular cyclisation products or polymeric materials. However, high ketones yields are obtained by using the new IBX method.

  6. 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.

  7. Beyond ketonization: selective conversion of carboxylic acids to olefins over balanced Lewis acid–base pairs

    Energy Technology Data Exchange (ETDEWEB)

    Baylon, Rebecca A. L.; Sun, Junming; Martin, Kevin J.; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-01

    Dwindling petroleum reserves combined with increased energy demand and political factors encouraging an increase in energy independence have led to a large amount of research on sustainable alternatives. To this end, biomass conversion has been recognized as themost readily viable technology to produce biofuel concerning our reliance on liquid fuels for transportation and has the advantage of being easily integrated into our heavy use of combustion engines. The interest in biomass conversion has also resulted in reduced costs and a greater abundance of bio-oil, a mixture of hundreds of oxygenates including alcohols, aldehydes, carboxylic acids, and ketones. However, the presence of carboxylic acids in bio-oil derived from lignocellulose pyrolysis leads to low pH, instability, and corrosiveness. In addition, carboxylic acids (i.e. acetic acid) can also be produced via fermentation of sugars. This can be accomplished by a variety of homoacetogenic microorganisms that can produce acetic acid with 100% carbon yield.

  8. Palladium(II)-Catalyzed Tandem Synthesis of Acenes Using Carboxylic Acids as Traceless Directing Groups.

    Science.gov (United States)

    Kim, Kiho; Vasu, Dhananjayan; Im, Honggu; Hong, Sungwoo

    2016-07-18

    A straightforward synthetic strategy for generating useful anthracene derivatives was developed involving palladium(II)-catalyzed tandem transformation with carboxylic acids as traceless directing groups. Carboxyl-directed C-H alkenylation, carboxyl-directed secondary C-H activation and rollover, intramolecular C-C bond formation, and decarboxylative aromatization are proposed as the key steps in the tandem reaction pathway. This novel synthetic route utilizes a broad range of substrates and provides a convenient synthetic tool that allows access to acenes. PMID:27244536

  9. Measuring the concentration of carboxylic acid groups in torrefied spruce wood.

    Science.gov (United States)

    Khazraie Shoulaifar, Tooran; Demartini, Nikolai; Ivaska, Ari; Fardim, Pedro; Hupa, Mikko

    2012-11-01

    Torrefaction is moderate thermal treatment (∼200-300°C) to improve the energy density, handling and storage properties of biomass fuels. In biomass, carboxylic sites are partially responsible for its hygroscopic. These sites are degraded to varying extents during torrefaction. In this paper, we apply methylene blue sorption and potentiometric titration to measure the concentration of carboxylic acid groups in spruce wood torrefied for 30min at temperatures between 180 and 300°C. The results from both methods were applicable and the values agreed well. A decrease in the equilibrium moisture content at different humidity was also measured for the torrefied wood samples, which is in good agreement with the decrease in carboxylic acid sites. Thus both methods offer a means of directly measuring the decomposition of carboxylic groups in biomass during torrefaction as a valuable parameter in evaluating the extent of torrefaction which provides new information to the chemical changes occurring during torrefaction.

  10. Expedited Synthesis of Benzofuran-2-Carboxylic Acids via Microwave-Assisted Perkin Rearrangement Reaction

    OpenAIRE

    Marriott, Karla-Sue C.; Bartee, Rena; Morrison, Andrew Z.; Stewart, Leonard; Wesby, Julian

    2012-01-01

    3-Halocoumarins are readily converted into benzofuran-2-carboxylic acids via a Perkin (coumarin-benzofuran ring contraction) rearrangement reaction. This rearrangement entails initial base catalyzed ring fission. The resulting phenoxide anion then attacks a vinyl halide to produce the final benzofuran moiety. We explored this reaction under microwave reaction conditions and were able to significantly reduce reaction times as well as obtain very high yields of a series of benzofuran-2-carboxyl...

  11. Chiral trans-1,2-diaminocyclohexane derivatives as chiral solvating agents for carboxylic acids

    Indian Academy of Sciences (India)

    Mariappan Periasamy; Manasi Dalai; Meduri Padmaja

    2010-07-01

    Efficient use of the readily accessible chiral 2-symmetric acyclic diamines (1-2) as well as macrocyclic amines (3-5) containing trans-1,2-diaminocyclohexyl moiety as chiral solvating agents (CSA) for the determination of enantiomeric excess of representative carboxylic acids (6-7) and an amino acid derivative (8) is illustrated. The enantiomeric composition of different carboxylic acids estimated here by the 1H NMR method, based on the integration of the corresponding methine proton signals are in good correlation with that determined using HPLC method. The data are in accordance with the formation of multimolecular diastereomeric complexes in solution, which render good splitting of NMR signals for the enantiomers of representative carboxylic acids as well as for -Ts-phenylglycine (up to = 0.295 ppm, 118 Hz).

  12. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes

    Science.gov (United States)

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O.; Knee, Joseph L.

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA—H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA—HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  13. Photosensitization of Nanocrystalline TiO2 Electrode Modifiedwith C60 Carboxylic Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    张文; 史亚茹; 甘良兵; 黄春辉; 王艳琴; 虎民

    2001-01-01

    C60 carboxylic acid derivatives can be readily adsorbed on the surface of nanocrystalline TiO2 films act as charge-transfer sensitizer. The electron transport from TiO2 to the C60 derivatives results in the generation of the cathodic photocurrent. The short-circuit photocurrent of a C60 tetracarboxylic acid is 0.45 μA/cm2 under 464 um light illumination. The photoelectric behaviour of ITO electrodes modified by the same C60 carboxylic acids is different from that of the modified TiO2 electrodes, and shows anodic photocurrent.

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

    International Nuclear Information System (INIS)

    The pseudotetrahedral complexes of [Cu(PPh3)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(PPh3)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%

  15. The investigation of the reactions of some pyrazole-3-carboxylic acids with various diamines and diols

    Directory of Open Access Journals (Sweden)

    Rahmi Kasımoğulları

    2012-06-01

    Full Text Available In this study, some new derivatives were synthesized of 4-benzoyl-1-(3-nitrophenyl-5-phenyl-1H-pyrazole-3-carboxylic acid (1 and 4-(ethoxycarbonyl-1-(3-nitrophenyl-5-phenyl-1H-pyrazole-3-carboxylic acid (2 that they were pyrazole carboxylic acid derivatives. Firstly, 1 and 2 reacted with SOCl2 to transform them into acyl chlorides (3, 4. Then various bis-carboxamide derivatives (5–8 were obtained from the reaction of 3 and 4 with various diamines and also a ;#946;-hydroxy ester (9 derivative was obtained from the reaction of 3 with ethylene glycol. The structures of synthesized compounds were elucidated with using FT-IR, 1H NMR, 13C NMR and elemental analysis methods.

  16. Crystal Structure and Properties of the Carboxylic Acid Derivatives of Schizonpeta mulifida (L.) Briq.

    Institute of Scientific and Technical Information of China (English)

    LIU,Ju-Tao; YU,Ji-Cheng; JIANG,Hui-Ming; ZHANG,Li-Ying; ZHAO,Xiao-Jing; FAN,Sheng-Di

    2008-01-01

    The chemical constituents of the carboxylic acid derivatives from the ear of Schizonepeta were investigated,1H and 13C NMR chemical shifts of the carboxylic acid derivatives were accurately assigned.Two carboxylic acid derivative constituents were separated by a silica gel column.The structures were elucidated by the physical and chemical properties,IR,1H NMR,13C NMR,MALDI-TDF-MS and X-ray single crystal diffractometry.They were identified as 3-imino-N-(a-imidoethylamino)butyrolactam and neononane tetracid,respectively.The antitumoral activity on liver tumor ceils SMMC-7721 was determined in vitro.The experimental results showed that the former was better than the latter,and with increasing the concentration of the former the inhibitory activity was increased.

  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

    ), 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.......The dielectric properties of several supramolecular ionic polymers and networks, linked by the ammonium salts of hexamethylene diamine (HMDA), tris(2-aminoethyl)amine (TAEA), poly(propylene imine) (PPI) dendrimers and two short bis carboxymethyl ether-terminated poly(ethylene glycol)s (Di...... 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...

  18. Simultaneous determination of C2-C22 non-esterified fatty acids and other metabolically relevant carboxylic acids in biological material by gas chromatography of their benzyl esters.

    Science.gov (United States)

    Schatowitz, B; Gercken, G

    1988-03-18

    A method for the simultaneous determination of non-esterified short-, medium- and long-chain fatty acids and other types of metabolically relevant carboxylic acids such as hydroxy, keto, aromatic and dicarboxylic acids in biological material by capillary gas chromatography of benzyl ester derivatives is described. Sample preparation avoiding incomplete isolation of carboxylic acids consisted of deproteinization and extraction with ethanol, fixation of carboxylic acids as carboxylates, removal of interfering compounds such as neutral lipids by hexane extraction and amino acids, acyl carnitines and other cations by cation-exchange chromatography, derivatization of keto groups of ketocarboxylic acids into O-methyl oximes and benzyl ester formation by reaction of the potassium carboxylates with benzyl bromide via crown ether catalysis. The sample preparation conditions were investigated, showing the usefulness of this method for quantitative determinations. Chromatograms obtained from human serum, human urine and rat heart ventricle and concentrations of carboxylic acids in these specimens are presented. PMID:3372640

  19. Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged alpha-zirconium phosphate.

    Science.gov (United States)

    Hayashi, A; Fujimoto, Y; Ogawa, Y; Nakayama, H; Tsuhako, M

    2005-03-01

    Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acidadsorption amount of formaldehyde was the same as that of butyric acid. It was cleared that the adsorbed formaldehyde was partially decomposed to formic acid and methanol by self oxidation-reduction reaction in the interlayer region as evidenced by solid-state NMR. Thereby the interlayer distance after the adsorption of formaldehyde expanded to 14.4 A. In the case of formic acid, it was cointercalated into the interlayer region, and the interlayer distance expanded to 11.1 A. On the other hand, the interlayer distance of the other carboxylic acid-adsorbed compounds decreased to 7.6 A due to release by the evacuation.

  20. Process for recovering carboxylic acids from sugar cane industry by-products

    OpenAIRE

    Albet, Joël; Pislor, Emilie; Pontalier, Pierre-Yves

    2009-01-01

    Food industry by-products such as molasses and vinasses may provide an important source of organic acids. The aim of this study is to compare three processes, precipitation, chromatography and liquid-liquid extraction, for the recovery of carboxylic acids from sugarcane molasses from Réunion Island. Precipitation was performed with different temperatures by addition of calcium chloride. The results revealed that precipitation can recover aconitic acid efficiently from molasses. Liquid-liquid ...

  1. Templating route for mesostructured calcium phosphates with carboxylic acid- and amine-type surfactants.

    Science.gov (United States)

    Ikawa, Nobuaki; Hori, Hideki; Kimura, Tatsuo; Oumi, Yasunori; Sano, Tsuneji

    2008-11-18

    Mesostructured calcium phosphates constructed by ionic frameworks were synthesized using carboxylic acid- and amine-type surfactants in mixed solvent systems of ethanol and water. A lamellar mesostructured calcium phosphate was prepared using palmitic acid as an anionic surfactant, as in the case using n-alkylamines. A wormhole-like mesostructured calcium phosphate can be obtained using dicarboxyl N-lauroyl- l-glutamic acid, whose headgroup is larger than that of palmitic acid. Similar mesostructured product was obtained using 4-dodecyldiethylenetriamine with a large headgroup containing two primary amine groups. Interactions of carboxyl and primary amino groups in the surfactant molecules with inorganic species are quite important for the formation of mesostructured calcium phosphates. The Ca/P molar ratio of mesostructured calcium phosphates was strongly affected by the molecular structure of surfactants containing carboxyl and primary amino groups. Ca-rich materials can be obtained using carboxylic acid-type surfactants (Ca/P approximately 1.7) rather than amine-type surfactants (Ca/P approximately 1.0). PMID:18947246

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

    International Nuclear Information System (INIS)

    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, 1H-and 13C- 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)

  3. Significant improvement in the pore properties of SBA-15 brought about by carboxylic acids and hydrothermal treatment

    Indian Academy of Sciences (India)

    Milan Kanti Naskar; M Eswaramoorthy

    2008-01-01

    A comparative study of the pore properties of SBA-15 samples prepared under nonhydrothermal and hydrothermal conditions, in the absence and presence of carboxylic acids such as succinic, tartaric and citric acids has been carried out. In the absence of carboxylic acid, flake-like and spheroid particles were generally obtained irrespective of the preparative procedures. On the other hand, stirring of the pre-mix induces a rod-like morphology in presence of carboxylic acids. The samples prepared under non-hydrothermal conditions exhibit a higher degree of silicate condensation compared to those synthesized under hydrothermal conditions. SBA-15 samples prepared under hydrothermal conditions show higher values of the d (100) spacing independent of the presence of carboxylic acids. Presence of carboxylic acids as well as hydrothermal treatment improves the pore properties of SBA-15.

  4. Z-effect reversal in carboxylic acid associates.

    Science.gov (United States)

    Medvedev, Michael G; Bushmarinov, Ivan S; Lyssenko, Konstantin A

    2016-05-01

    The carboxylic group is a common fragment in synthetic compounds and biomolecules. Its conformation is assumed to be dominantly cis due to so-called Z-effect. However, in this study, we show that the nature of the H-bond acceptor in RCOOHX directly affects the conformational preference of the resulting supermolecule. This result is evident from the statistical analysis of available crystallographic data and was quantified using accurate quantum chemical calculations. We propose the term "supramolecular stereoelectronic effect" for the observed conformational preference. The likely reason for this is the interaction of the O-HX hydrogen bond with the C[double bond, length as m-dash]O double bond in the trans conformation, which in case of anionic X is strong enough to reverse the Z-effect. Explicit consideration of trans COOHX stabilization can help crystal structure predictions and biomolecular simulations. In particular, this effect plays a key role in the transition between the T6 and R6 forms of human insulin. PMID:27109148

  5. Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters.

    Science.gov (United States)

    Li, Yuehui; Topf, Christoph; Cui, Xinjiang; Junge, Kathrin; Beller, Matthias

    2015-04-20

    Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. PMID:25728921

  6. 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.

  7. Ionic liquids as solvent for efficient esterification of carboxylic acids with alkyl halides

    OpenAIRE

    carboxylic, Ionic liquids as solvent for efficient e

    2010-01-01

    The selective esterification of carboxylic acid derivatives with a variety of alkyl halides was carried out using ionic liquid as solvent in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions (up to 99%) and selectivities. The ionic liquid was recycled and reused.

  8. Acyl Radicals from Aromatic Carboxylic Acids by Means of Visible-Light Photoredox Catalysis

    OpenAIRE

    Bergonzini, Giulia; Cassani, Carlo; Wallentin, Carl-Johan

    2015-01-01

    Simple and abundant carboxylic acids have been used as acyl radical precursor by means of visible-light photoredox catalysis. By the transient generation of a reactive anhydride intermediate, this redox-neutral approach offers a mild and rapid entry to high-value heterocyclic compounds without the need of UV irradiation, high temperature, high CO pressure, tin reagents, or peroxides.

  9. ANTI-CORROSION PROPERTIES OF CARBOXYLIC ACID IN WATER-GLYCOL SOLUTIONS

    Directory of Open Access Journals (Sweden)

    BASHKIRCEVA N.Y.

    2012-01-01

    Full Text Available Sodium salts of carboxylic acids were investigated to evaluate the corrosion properties of the water-glycol solutions. Corrosion tests were performed by methods of gravimetry and galvanostatic dissolution with metals used in cooling systems. The compositions of anticorrosion systems and their concentration that provide the most effective inhibition of metals were determined.

  10. Multilayer Film Fabrication and Photoelectric Conversion Property of Two Pyrrolidinofullerene Carboxylic Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two multilayer films of pyrrolidinofullerene carboxylic acid derivatives, which exhibit photoelectric conversion property, are reported here. The first monolayers were fabricated on hydrophilic indium-tin-oxide (ITO), quartz, and mica by esterification reaction. The multilayers were characterized by contact angle and UV spectrum. The photoelectric conversion properties of both multilayer films were studied.

  11. A Novel Metal-free Reductive Esterification of N-Tosylhydrazones with Carboxylic Acids

    Institute of Scientific and Technical Information of China (English)

    周安坤; 吴磊; 李大志; 陈庆庆; 张晓; 夏吾炯

    2012-01-01

    A novel method for the synthesis of esters via reductive coupling of N-tosylhydrazones with carboxylic acids under metal-free conditions has been developed. Various functional groups were found to be tolerable under the re- action conditions to afford low to good yields.

  12. 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.

  13. CATALYTIC ESTERIFICATION OF CARBOXYLIC ACIDS WITH ALCOHOLS BY SULFO—POLYVINYL CHLORIDE

    Institute of Scientific and Technical Information of China (English)

    YuShanxin; ZHAOZongbao; 等

    1993-01-01

    Polyvinyl Chloride reacted with chlorosulfonic acid to from a polymer catalyst PVC-SO3H.This polymer catalyst was found to have high activity for resterification reaction between carboxylic acids and alcohols.This paper deals with the conditions in synthesis of n-butlyacetate catalyzed with PVC-SO3H.The PVC-SO3H was used as a catalyst for preparing 11 esters of acetic acid,propionic acid and butyric acid with the yields of 82-92%.

  14. Unique adsorption behaviors of carboxylic acids at rutile TiO2(110)

    Science.gov (United States)

    Yu, Yan-Yan; Gong, Xue-Qing

    2015-11-01

    The coverage-dependent adsorption behavior of acetic acid (CH3COOH) on rutile TiO2(110) was investigated by means of density functional theory (DFT) calculations, corrected by on-site Coulomb corrections and long-range dispersion interactions. The p(2 × 1) and c(2 × 2) domains of dissociatively adsorbed acetic acid under different coverages have been studied in detail regarding their structural and energetic properties. Adsorptions of formic acid (HCOOH) and carbonic acid (H2CO3) were also considered for better understanding the adsorption behaviors of carboxylic acids. Our calculation results show that carboxylic acids prefer to dissociatively adsorb in bridging bidentate configuration, and it induces significant surface relaxation at the adsorption site, which also affects other surface atoms nearby. Interestingly, we have shown that such adsorption-induced relaxations still maintain bond symmetries for surface Ti cations within the p(2 × 1) domain while they are drastically broken within the c(2 × 2) domain, giving rise to unstable Ti cations at the surface. This work not only explains the long-lasting puzzle of the preferable occurrence of p(2 × 1) domain for the adsorbed carboxylic acids at rutile TiO2(110), it also proposes a novel scheme that metal oxide surfaces may follow when they are involved in the processes like surface functionalization and self-assembly.

  15. (±)-trans-3-Benzoyl-bicyclo-[2.2.2]octane-2-carboxylic acid.

    Science.gov (United States)

    Lalancette, Roger A; Thompson, Hugh W; Brunskill, Andrew P J

    2008-01-01

    The title keto acid, C(16)H(18)O(3), displays significant twisting of all three ethyl-ene bridges in its bicyclo-[2.2.2]octane structure owing to steric inter-actions; the bridgehead-to-bridgehead torsion angles are 13.14 (12), 13.14 (13) and 9.37 (13)°. The compound crystallizes as centrosymmetric carboxyl dimers [O⋯O = 2.6513 (12) Å and O-H⋯O = 178°], which have two orientations within the cell and contain no significant carboxyl disorder. PMID:21201657

  16. (±-trans-3-Benzoylbicyclo[2.2.2]octane-2-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Andrew P. J. Brunskill

    2008-09-01

    Full Text Available The title keto acid, C16H18O3, displays significant twisting of all three ethylene bridges in its bicyclo[2.2.2]octane structure owing to steric interactions; the bridgehead-to-bridgehead torsion angles are 13.14 (12, 13.14 (13 and 9.37 (13°. The compound crystallizes as centrosymmetric carboxyl dimers [O...O = 2.6513 (12 Å and O—H...O = 178°], which have two orientations within the cell and contain no significant carboxyl disorder.

  17. 5,6-dihydroxyindole-2-carboxylic acid (DHICA): a First Principles Density-Functional Study

    CERN Document Server

    Powell, B J

    2016-01-01

    We report first principles density functional calculations for 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and several reduced forms. DHICA and 5,6-dihydroxyindole (DHI) are believed to be the basic building blocks of the eumelanins. Our results show that carboxylation has a significant effect on the physical properties of the molecules. In particular, the relative stabilities and the HOMO-LUMO gaps (calculated with the $\\Delta$SCF method) of the various redox forms are strongly affected. We predict that, in contrast to DHI, the density of unpaired electrons, and hence the ESR signal, in DHICA is negligibly small.

  18. Factors influencing the rate of non-enzymatic activation of carboxylic and amino acids by ATP

    Science.gov (United States)

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1981-01-01

    The nonenzymatic formation of adenylate anhydrides of carboxylic and amino acids is discussed as a necessary step in the origin of the genetic code and protein biosynthesis. Results of studies are presented which have shown the rate of activation to depend on the pKa of the carboxyl group, the pH of the medium, temperature, the divalent metal ion catalyst, salt concentration, and the nature of the amino acid. In particular, it was found that of the various amino acids investigated, phenylalanine had the greatest affinity for the adenine derivatives adenosine and ATP. Results thus indicate that selective affinities between amino acids and nucleotides were important during prebiotic chemical evolution, and may have played a major role in the origin of protein synthesis and genetic coding.

  19. Transition-Metal-Free Decarboxylative Photoredox Coupling of Carboxylic Acids and Alcohols with Aromatic Nitriles.

    Science.gov (United States)

    Lipp, Benjamin; Nauth, Alexander M; Opatz, Till

    2016-08-01

    A transition-metal-free protocol for the redox-neutral light-induced decarboxylative coupling of carboxylic acids with (hetero)aromatic nitriles at ambient temperature is presented. A broad scope of acids and nitriles is accepted, and alcohols can be coupled in a similar fashion through their oxalate half esters. Various inexpensive sources of UV light and even sunlight can be used to achieve this C-C bond formation proceeding through a free radical mechanism. PMID:27399619

  20. Structure–anticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives

    OpenAIRE

    Lesyk R. B.; Kaminskyy D. V.

    2010-01-01

    The aim of present research was investigation of anticancer activity of 4-azolidinone-3-carboxylic acids derivatives, and studies of structure–activity relationships (SAR) aspects. Methods. Organic synthesis; spectral methods; anticancer screening was performed according to the US NCI protocol (Developmental Therapeutic Program). Results. The data of new 4-thiazolidinone-3-alkanecarboxylic acids derivatives in vitro anticancer activity were described. The most active compounds which belong to...

  1. A novel application of horseradish peroxidase: Oxidation of alcohol ethoxylate to alkylether carboxylic acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel application of horseradish peroxidase (HRP) in the oxidation of alcohol ethoxylate to alkylether carboxylie acid in the present of H2O2 was reported in this paper. We propose the mechanism for the catalytic oxidation reaction is that the hydrogen transfers from the substrate to the ferryl oxygen to form the a-hydroxy carbon radical intermediate. The reaction offers a new approach for further research structure and catalytic mechanism of HRP and production of alkylether carboxylic acid.

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

    OpenAIRE

    Akhtar, M. K.; Turner, N. J.; Jones, P R

    2012-01-01

    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 Mycobac...

  3. Citraturic response to oral citric acid load

    Science.gov (United States)

    Sakhaee, K.; Alpern, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    It is possible that some orally administered citrate may appear in urine by escaping oxidation in vivo. To determine whether this mechanism contributes to the citraturic response to potassium citrate, we measured serum and urinary citrate for 4 hours after a single oral load of citric acid (40 mEq.) in 6 normal subjects. Since citric acid does not alter acid-base balance, the effect of absorbed citrate could be isolated from that of alkali load. Serum citrate concentration increased significantly (p less than 0.05) 30 minutes after a single oral dose of citric acid and remained significantly elevated for 3 hours after citric acid load. Commensurate with this change, urinary citrate excretion peaked at 2 hours and gradually decreased during the next 2 hours after citric acid load. In contrast, serum and urinary citrate remained unaltered following the control load (no drug). Differences of the citratemic and citraturic effects between phases were significant (p less than 0.05) at 2 and 3 hours. Urinary pH, carbon dioxide pressure, bicarbonate, total carbon dioxide and ammonium did not change at any time after citric acid load, and did not differ between the 2 phases. No significant difference was noted in serum electrolytes, arterialized venous pH and carbon dioxide pressure at any time after citric acid load and between the 2 phases. Thus, the citraturic and citratemic effects of oral citric acid are largely accountable by provision of absorbed citrate, which has escaped in vivo degradation.

  4. Surface modification of semiconductor nanocrystals by a methanofullerene carboxylic acid

    NARCIS (Netherlands)

    Szendrei, Krisztina; Jarzab, Dorota; Yarema, Maksym; Sytnyk, Mikhael; Pichler, Stefan; Hummelen, Jan C.; Heiss, Wolfgang; Loi, Maria A.

    2010-01-01

    We report, for the first time, on successful binding of a fullerene derivative, namely 3,4-dihexyloxyphenyl-C(61)-butyric-acid (dPCBA) to PbS and CdSe nanocrystals (NCs). This molecule is an excellent candidate to serve as electroactive ligand for NCs and form novel complexes, which could be very pr

  5. Plastic scintillators with high loading of one or more metal carboxylates

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, Nerine; Sanner, Robert Dean

    2016-09-20

    According to one embodiment, a method includes incorporating a metal carboxylate complex into a polymeric matrix to form an optically transparent material. According to another embodiment, a material includes at least one metal carboxylate complex incorporated into a polymeric matrix, where the material is optically transparent.

  6. ANALYSIS OF AIRBORNE CARBOXYLIC ACIDS AND PHENOLS AS THEIR PENTAFLUOROBENZYL DERIVATIVES: GAS CHROMATOGRAPHY/ION TRAP MASS SPECTROMETRY WITH A NOVEL CHEMICAL IONIZATION REAGENT, PFBOH. (R826247)

    Science.gov (United States)

    The complex photochemical transformations of biogenichydrocarbons such as isoprene and of anthropogenichydrocarbons such as aromatics are an important sourceof carboxylic acids in the troposphere. Theidentificationof unknown carboxylic acids can be difficul...

  7. 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.

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

    Science.gov (United States)

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

    2016-06-01

    The formation of pyridine carboxylic acids in interstellar ice grains was simulated by electron exposures of binary pyridine (C5H5N)-carbon dioxide (CO2) 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-C5H4NCOOH) along with 2,3-, 2,5-, 3,4-, and 3,5-pyridine dicarboxylic acid (C5H3N(COOH)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.

  9. 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.

  10. Cyclopentane-1,3-dione: A Novel Isostere for the Carboxylic Acid Functional Group. Application to the Design of Potent Thromboxane (A2)-Receptor Antagonists

    OpenAIRE

    Ballatore, Carlo; Soper, James; Piscitelli, Francesco; James, Michael; Huang, Longchuan; Atasoylu, Onur; Huryn, Donna M.; Trojanowski, John Q.; Lee, Virginia M.-Y.; Brunden, Kurt R.; Smith, Amos B.

    2011-01-01

    Cyclopentane-1,3-diones are known to exhibit pKa values typically in the range of carboxylic acids. To explore the potential of the cyclopentane-1,3-dione unit as a carboxylic acid isostere, the physical-chemical properties of representative congeners were examined and compared with similar derivatives bearing carboxylic acid or tetrazole residues. These studies suggested that cyclopentane-1,3-diones may effectively substitute for the carboxylic acid functional group. To demonstrate the use o...

  11. 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.)

  12. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    International Nuclear Information System (INIS)

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed

  13. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Saikat; Wu, Kevin C.-W., E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kao, Hsien-Ming, E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)

    2014-11-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and {sup 13}C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  14. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Science.gov (United States)

    Dutta, Saikat; Kao, Hsien-Ming; Wu, Kevin C.-W.

    2014-11-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (-COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  15. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Directory of Open Access Journals (Sweden)

    Saikat Dutta

    2014-11-01

    Full Text Available This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs functionalized with carboxylic acid (–COOH group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  16. Rapid and selective derivatizatin method for the nitrogen-sensitive detection of carboxylic acids in biological fluids prior to gas chromatographic analysis

    NARCIS (Netherlands)

    Lingeman, H.; Haan, H.B.P.; Hulshoff, A.

    1984-01-01

    A rapid and selective derivatization procedure is described for the pre-column labelling of carboxylic acids with a nitrogen-containing label. The carboxylic acid function is activated with 2-bromo-1-methylpyridinium iodide and the activated carboxylic acid function reacts with a primary or a second

  17. DETERMINATION OF CARBOXYLIC ACIDS BY ION-EXCLUSION CHROMATOGRAPHY WITH NON-SUPPRESSED CONDUCTIVITY AND OPTICAL DETECTORS

    Science.gov (United States)

    Determination of carboxylic acids using non-suppressed conductivity and UV detections is described. The background conductance of 1-octanesulfonic acid, hexane sulfonic acid and sulfuric acid at varying concentrations was determined. Using 0.2 mM 1-octanesulfonic acid as a mobile...

  18. 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...... by hydrolysis of beta-lactam ring and eventually further chemical modifications of a citrate-containing penicillin. Copyright (C) 1996 Elsevier Science Ltd...

  19. Plastic scintillators with high loading of one or more metal carboxylates

    Science.gov (United States)

    Cherepy, Nerine; Sanner, Robert Dean

    2016-01-12

    In one embodiment, a material includes at least one metal compound incorporated into a polymeric matrix, where the metal compound includes a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands includes a tertiary butyl group, and where the material is optically transparent. In another embodiment, a method includes: processing pulse traces corresponding to light pulses from a scintillator material; and outputting a result of the processing, where the scintillator material comprises at least one metal compound incorporated into a polymeric matrix, the at least one metal compound including a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands has a tertiary butyl group, and where the scintillator material is optically transparent and has an energy resolution at 662 keV of less than about 20%.

  20. Redshift or adduct stabilization -- a computational study of hydrogen bonding in adducts of protonated carboxylic acids

    DEFF Research Database (Denmark)

    Olesen, Solveig Gaarn; Hammerum, Steen

    2009-01-01

    not always yield consistent predictions, as illustrated by the hydrogen bonds formed by the E and Z OH groups of protonated carboxylic acids. The delta-PA and the stabilization of a series of hydrogen bonded adducts indicate that the E OH group forms the stronger hydrogen bonds, whereas the bond length...... carboxylic acids are different. The OH bond length and IR redshift afford the better measure of hydrogen bond strength.......It is generally expected that the hydrogen bond strength in a D-H-A adduct is predicted by the difference between the proton affinities of D and A, measured by the adduct stabilization, and demonstrated by the IR redshift of the D-H bond stretching vibrational frequency. These criteria do...

  1. 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.

  2. 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.

  3. Catalytic conversion of carboxylic acids in bio-oil for liquid hydrocarbons production

    International Nuclear Information System (INIS)

    Bio-oil must be upgraded to be suitable for use as a high-grade transport fuel. Crude bio-oil has a high content of carboxylic acids which can cause corrosion, and the high oxygen content of these acids also reduces the oil’s heating value. In this paper, acetic acid and propanoic acid were chosen as the model carboxylic acids in bio-oil. Their behavior in the production of liquid hydrocarbons during a catalytic conversion process was investigated in a micro-fixed bed reactor. The liquid organic phase from this catalytic conversion process mainly consisted of liquid hydrocarbons and phenol derivatives. Under the condition of low Liquid Hourly Space Velocity (LHSV), the liquid organic phase from acetic acid cracking had a selectivity of 22% for liquid hydrocarbons and a selectivity of 65% for phenol derivatives. The composition of the organic products changed considerably with the LHSV increasing to 3 h−1. The selectivity for liquid hydrocarbons increased up to 52% while that for phenol derivatives decreased to 32%. Propanoic acid performed much better in producing liquid hydrocarbons than acetic acid. Its selectivity for liquid hydrocarbons was as high as 80% at LHSV = 3 h−1. A mechanism for this catalytic conversion process was proposed according to the analysis of the components in the liquid organic phases. The pathways of the main compounds formation in the liquid organic phases were proposed, and the reason why liquid hydrocarbons were more effectively produced when using propanoic acid rather than acetic acid was also successfully explained. In addition, BET and SEM characterization were used to analyze the catalyst coke deposition. -- Graphical abstract: Display Omitted Highlights: ► High content of carboxylic acids in bio-oil causes its corrosiveness. ► Acetic acid and propanoic acid are two dominant acids in bio-oil. ► Liquid hydrocarbons were produced by cracking of these two dominant acids. ► A mechanism model was proposed to explain the

  4. Wind tunnel investigations on the retention of carboxylic acids during riming

    Science.gov (United States)

    Jost, Alexander; Szakáll, Miklós; Diehl, Karoline; Mitra, Subir K.; Borrmann, Stephan

    2015-04-01

    In mid-latitudes, precipitation is mainly initiated via the ice phase in mixed phase clouds. In such clouds the ice particles grow to precipitation sizes at the expense of liquid drops through riming which means that supercooled droplets collide with ice particles and subsequently freeze. Water-soluble trace substances present in the liquid phase might remain only fractionally in the ice phase after freezing. This fractionation is called retention and is an important ratio which quantifies the partitioning of atmospheric trace substances between the phases. Laboratory experiments were carried out at the Mainz vertical wind tunnel to determine the retention of lower mono- and di-carboxylic acids during riming. Due to their low molecular weight and their polarity these acids are water-soluble. In the atmosphere formic acid and acetic acid are the most abundant mono-carboxylic acids in the gas and aqueous phase, thus, they represent the major fraction of carboxylic acids in cloud water. Oxalic and malonic acid are common coatings on aerosol particles because of their relatively low saturation vapor pressure. These di-carboxylic acids might therefore promote the aerosol particles to act as cloud condensation nuclei and additionally contribute to the aqueous phase chemistry in cloud droplets. The conditions during the riming experiments in the wind tunnel were similar to those in atmospheric mixed phase clouds, i.e. temperatures from -18°C to -6 °C, liquid water contents between 0.5 and 1.5 g/m3, and liquid drop radii between 10 and 20 μm. The liquid phase concentrations ranged from 3 to 5 mg/l (4.1 water was analyzed by ion chromatography and the retention coefficients, i.e. the fractions of the species which remained in the ice phase were determined. Average retention coefficients of formic acid and acetic acid were 0.73 ± 0.07 and 0.62 ± 0.12, respectively; both oxalic and malonic acids had average retention coefficients of 0.98 ± 0.04. These variations can be

  5. Chemical Analysis and Transplacental Transfer of Oseltamivir and Oseltamivir Carboxylic Acid in Pregnant Rats

    OpenAIRE

    Lin, Chia-Chun; Yen, Jiin-Cherng; Wu, Yu-Tse; Lin, Lie-Chwen; Tsai, Tung-Hu

    2012-01-01

    In view of the limited information on the pharmacokinetics of oseltamivir (OSE) during pregnancy, this study aims to evaluate the placental transportation of OSE and its active metabolite oseltamivir carboxylic acid (OCA) in rats. A validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) system coupled to an in vivo transplacental model has been developed to determine OSE and OCA in the placenta, amniotic fluids and fetus of 13-day pregnant Sprague-Dawley rats. Concentrations of O...

  6. 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

    2015-06-01

    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.

  7. Hydrolytic activity of -alkoxide/acetato-bridged binuclear Cu(II) complexes towards carboxylic acid ester

    Indian Academy of Sciences (India)

    Weidong Jiang; Bin Xu; Zhen Xiang; Shengtian Huang; Fuan Liu; Ying Wang

    2013-09-01

    Two -alkoxide/acetate-bridged small molecule binuclear copper(II) complexes were synthesized, and used to promote the hydrolysis of a classic carboxylic acid ester, -nitrophenyl picolinate (PNPP). Both binuclear complexes exhibited good hydrolytic reactivity, giving rise to . 15547- and 17462-fold acceleration over background value for PNPP hydrolysis at neutral conditions, respectively. For comparing, activities of the other two mononuclear analogues were evaluated, revealing that binuclear complexes show approximately 150- and 171-fold kinetic advantage over their mononuclear analogues.

  8. Enantioselective CuH-Catalyzed Reductive Coupling of Aryl Alkenes and Activated Carboxylic Acids.

    Science.gov (United States)

    Bandar, Jeffrey S; Ascic, Erhad; Buchwald, Stephen L

    2016-05-11

    A new method for the enantioselective reductive coupling of aryl alkenes with activated carboxylic acid derivatives via copper hydride catalysis is described. Dual catalytic cycles are proposed, with a relatively fast enantioselective hydroacylation cycle followed by a slower diastereoselective ketone reduction cycle. Symmetrical aryl carboxyclic anhydrides provide access to enantioenriched α-substituted ketones or alcohols with excellent stereoselectivity and functional group tolerance. PMID:27121395

  9. Novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids as calcium activated chloride channel inhibitors

    OpenAIRE

    Kumar, Satish; Namkung, Wan; A S Verkman; Sharma, Pawan K

    2012-01-01

    Transmembrane protein 16A (TMEM16A) channels are recently discovered membrane proteins that functions as a calcium activated chloride channel (CaCC). CaCCs are major regulators of various physiological processes, such as sensory transduction, epithelial secretion, smooth muscle contraction and oocyte fertilization. Thirty novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids (B01–B30) were synthesized and evaluated for their TMEM16A inhibitory activity by using short circuit curre...

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

    OpenAIRE

    Buckholtz, Gavin A.; Gawalt, Ellen S.

    2012-01-01

    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 aero...

  11. Ciprofloxacin, a quinolone carboxylic acid compound active against aerobic and anaerobic bacteria.

    OpenAIRE

    Chin, N X; Neu, H C

    1984-01-01

    The in vitro activity of ciprofloxacin, a quinolone-carboxylic acid derivative, was compared with those of norfloxacin, cefotaxime, cephalexin, ceftazidime, moxalactam, amoxicillin, and methicillin and other agents, as appropriate. The MICs of ciprofloxacin for 90% of members of the family Enterobacteriaceae and for Pseudomonas aeruginosa, Neisseria spp., and Bacteroides fragilis were between 0.005 and 0.8 micrograms/ml, whereas streptococci and staphylococci were all inhibited by less than o...

  12. 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...... 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....

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

    OpenAIRE

    Katarina Kralova; Jiri Kunes; Miroslav Miletin; Martin Dolezal

    2002-01-01

    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-carbo...

  14. Carboxylic Acid Fullerene (C60) Derivatives Attenuated Neuroinflammatory Responses by Modulating Mitochondrial Dynamics

    Science.gov (United States)

    Ye, Shefang; Zhou, Tong; Cheng, Keman; Chen, Mingliang; Wang, Yange; Jiang, Yuanqin; Yang, Peiyan

    2015-05-01

    Fullerene (C60) derivatives, a unique class of compounds with potent antioxidant properties, have been reported to exert a wide variety of biological activities including neuroprotective properties. Mitochondrial dynamics are an important constituent of cellular quality control and function, and an imbalance of the dynamics eventually leads to mitochondria disruption and cell dysfunctions. This study aimed to assess the effects of carboxylic acid C60 derivatives (C60-COOH) on mitochondrial dynamics and elucidate its associated mechanisms in lipopolysaccharide (LPS)-stimulated BV-2 microglial cell model. Using a cell-based functional screening system labeled with DsRed2-mito in BV-2 cells, we showed that LPS stimulation led to excessive mitochondrial fission, increased mitochondrial localization of dynamin-related protein 1 (Drp1), both of which were markedly suppressed by C60-COOH pretreatment. LPS-induced mitochondria reactive oxygen species (ROS) generation and collapse of mitochondrial membrane potential (Δ Ψm) were also significantly inhibited by C60-COOH. Moreover, we also found that C60-COOH pretreatment resulted in the attenuation of LPS-mediated activation of nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling, as well as the production of pro-inflammatory mediators. Taken together, these findings demonstrated that carboxylic acid C60 derivatives may exert neuroprotective effects through regulating mitochondrial dynamics and functions in microglial cells, thus providing novel insights into the mechanisms of the neuroprotective properties of carboxylic acid C60 derivatives.

  15. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  16. 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...

  17. Using the Chiral Organophosphorus Derivatizing Agents for Determination of the Enantiomeric Composition of Chiral Carboxylic Acids by 31PNMR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Chao CHE; Zhong Ning ZHANG; Gui Lan HUANG; Xin Xing WANG; Zhao Hai QIN

    2004-01-01

    The use of chiral organophosphorus derivatizing agents prepared in situ from chiral tartrate or chiral diamine for the 31PNMR determination of the enantiomeric composition of chiral carboxylic acids is described. The method is accurate, reliable and convenient.

  18. Aldehydes, ketones, and carboxylic acids formed radiolytically in aqueous solutions of cyanides and simple nitriles

    International Nuclear Information System (INIS)

    A systematic search for aldehydes, ketones, and carboxylic acids was carried out in aqueous solutions of HCN, NH4CN, CH3CN, and C2H4CN, that had received multikilogray doses of 60Co γ radiation. About 30 radiolytic products were identified, among them a large variety of dicarboxylic and tricarboxylic acids. Some of them might be of significant interest in molecular evolution studies of prebiotic processes. They originate in the free-radical-initiated chemical reactions where the additional oligomerization processes are particularly important. Most of the radiolytic products appear in both cyanides and nitriles and point to the importance of reactions involving the carbon-nitrogen triple bond

  19. A Convenient, General Synthesis of 1,1-Dimethylallyl Esters as Protecting Groups for Carboxylic Acids

    Science.gov (United States)

    Sedighi, Minoo; Lipton, Mark A.

    2006-01-01

    Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided. PMID:15816730

  20. A convenient, general synthesis of 1,1-dimethylallyl esters as protecting groups for carboxylic acids.

    Science.gov (United States)

    Sedighi, Minoo; Lipton, Mark A

    2005-04-14

    [reaction: see text] Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl, and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided.

  1. The Structure-Activity Relationship of an Ozonide Carboxylic Acid (OZ78) Against Fasciola hepatica

    OpenAIRE

    Zhao, Qingjie; Vargas, Mireille; Dong, Yuxiang; ZHOU, Lin; Wang, Xiaofang; Sriraghavan, Kamaraj; Keiser, Jennifer; Vennerstrom, Jonathan L.

    2010-01-01

    In this paper, we describe the SAR of ozonide carboxylic acid OZ78 (1) as the first part of our search for a trematocidal synthetic peroxide drug development candidate. We found that relatively small structural changes to 1 resulted most commonly in loss of activity against Fasciola hepatica in vivo. A spiroadamantane substructure and acidic functional group (or ester prodrug) were required for activity. Of twenty-six new compounds administered at single 100 mg/kg oral doses to F. hepatica-in...

  2. Gas-Phase Amidation of Carboxylic Acids with Woodward's Reagent K Ions

    Science.gov (United States)

    Peng, Zhou; Pilo, Alice L.; Luongo, Carl A.; McLuckey, Scott A.

    2015-06-01

    Gas-phase amidation of carboxylic acids in multiply-charged peptides is demonstrated via ion/ion reactions with Woodward's reagent K (wrk) in both positive and negative mode. Woodward's reagent K, N-ethyl-3-phenylisoxazolium-3'-sulfonate, is a commonly used reagent that activates carboxylates to form amide bonds with amines in solution. Here, we demonstrate that the analogous gas-phase chemistry occurs upon reaction of the wrk ions and doubly protonated (or doubly deprotonated) peptide ions containing the carboxylic acid functionality. The reaction involves the formation of the enol ester intermediate in the electrostatic complex. Upon collisional activation, the ethyl amine on the reagent is transferred to the activated carbonyl carbon on the peptide, resulting in the formation of an ethyl amide (addition of 27 Da to the peptide) with loss of a neutral ketene derivative. Further collision-induced dissociation (CID) of the products and comparison with solution-phase amidation product confirms the structure of the ethyl amide.

  3. Investigation of Carboxylic Acid-Neodymium Conversion Films on Magnesium Alloy

    Science.gov (United States)

    Cui, Xiufang; Liu, Zhe; Lin, Lili; Jin, Guo; Wang, Haidou; Xu, Binshi

    2015-01-01

    The new carboxylic acid-neodymium anhydrous conversion films were successfully prepared and applied on the AZ91D magnesium alloy surface by taking absolute ethyl alcohol as solvent and four kinds of soluble carboxylic acid as activators. The corrosion resistance of the coating was measured by potentiodynamic polarization test in 3.5 wt.% NaCl solution in pH 7.0. The morphology, structure, and constituents of the coating were observed by scanning electron microscope, energy dispersivespectrum, x-ray photoelectron spectrum, and Fourier infrared spectrometer. Results show that corrosion resistance properties of samples coated with four different anhydrous conversion films were improved obviously. The corrosion potential increased, corrosion current density decreased, and polarization resistance increased. Among these four kinds of conversion films the one added with phytic exhibits the best corrosion resistant property. The mechanism of anhydrous-neodymium conversion film formation is also analyzed in this paper. It reveals that the gadolinium conversion coating is mainly composed of stable Nd2O3, MgO, Mg(OH)2, and carboxylate of Nd. And that the sample surface is rich in organic functional groups.

  4. Ruthenium(II) multi carboxylic acid complexes: chemistry and application in dye sensitized solar cells.

    Science.gov (United States)

    Shahroosvand, Hashem; Nasouti, Fahimeh; Sousaraei, Ahmad

    2014-04-01

    Novel ruthenium multi carboxylic complexes (RMCCs) have been synthesized by using ruthenium nitrosyl nitrate, 1,2,4,5-benzenetetracarboxylic acid (H4btec) and 4,7-diphenyl-1,10-phenanthroline (BPhen) as photosensitizers for titanium dioxide semiconductor solar cells. The complexes were characterized by (1)H-NMR, FT-IR, UV-Vis, ICP and CHN analyses. The reaction details and features were then described. SEM analysis revealed that the penetration of dyes into the pores of the nanocrystalline TiO2 surface was improved by increasing the number of btec units. The solar energy to electricity conversion efficiency of complexes shows that the number of attached carboxylates on a dye has an influence on the photoelectrochemical properties of the dye-sensitized electrode. An incident photon-to-current conversion efficiency (IPCE) of 13% at 510 nm was obtained for ruthenium complexes with three btec units. PMID:24500312

  5. Recovery of carboxylic acids at pH greater than pK{sub a}

    Energy Technology Data Exchange (ETDEWEB)

    Tung, L.A.

    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 > pK{sub a} and regenerability depend on sorbent basicity; apparent pK{sub a} 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.

  6. Determination of the thermodynamic quantities of complexation between Eu(III) and carboxylic acids by microcalorimetry

    International Nuclear Information System (INIS)

    Potentiometric and microcalorimetric titration techniques were applied to determine the Gibbs free energies and enthalpies of the protonation of some carboxylic acids (acetic, glycolic, malonic and malic acids) and their complexation with Eu(III) in 1.0 M NaClO4 solution at 25 C, where Eu(III) was used as a chemical analogue of radiologically important Am(III). By using the values of ΔG determined by potentiometric titrations, the results of calorimetric titrations were analyzed to give the values of ΔH and ΔS. To support the discussion on the obtained thermodynamic quantities, the hydration numbers of Eu(III) in the complexes were obtained by TRLFS measurement, where the luminescence lifetime of Eu(III) excited by 394 nm laser was measured. A few to several kJ/mol of enthalpies were determined for the reactions within the uncertainties of ±0.01 to ±0.4. These enthalpy values indicated that the protonation of these carboxylates were entropy-driven, that is, vertical stroke - TΔS vertical stroke >> vertical stroke ΔH vertical stroke in ΔG = ΔH - TΔS. The complexations of Eu(III) were also shown to be controlled mainly by entropy term. The results of TRLFS measurement revealed that the number of dehydrated water molecule increased with the degree of complexation. A linear relation was found between total entropy change of the system (ΔST) and the net number of released molecules from the central Eu(III) ion. However, the values of ΔST for the hydroxy-carboxylates were smaller than that for simple carboxylates at the same net number of molecules released from Eu(III), suggesting that the dehydration occurred not only in the cation but also in the anion. (orig.)

  7. 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. PMID:26361086

  8. Structure of eight molecular salts assembled from noncovalent bonding between carboxylic acids, imidazole, and benzimidazole

    Science.gov (United States)

    Jin, Shouwen; Zhang, Huan; Liu, Hui; Wen, Xianhong; Li, Minghui; Wang, Daqi

    2015-09-01

    Eight organic salts of imidazole/benzimidazole have been prepared with carboxylic acids as 2-methyl-2-phenoxypropanoic acid, α-ketoglutaric acid, 5-nitrosalicylic acid, isophthalic acid, 4-nitro-phthalic acid, and 3,5-dinitrosalicylic acid. The eight crystalline forms reported are proton-transfer compounds of which the crystals and compounds were characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. These structures adopted hetero supramolecular synthons, with the most common R22(7) motif observed at salts 2, 3, 5, 6 and 8. Analysis of the crystal packing of 1-8 suggests that there are extensive strong Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between acid and imidazolyl components in all of the salts. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. This variety, coupled with the varying geometries and number of acidic groups of the acids utilized, has led to the creation of eight supramolecular arrays with 1D-3D structure. The role of weak and strong noncovalent interactions in the crystal packing is analyzed. The results presented herein indicate that the strength and directionality of the Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds between acids and imidazole/benzimidazole are sufficient to bring about the formation of organic salts.

  9. Carboxylic acid derivatives via catalytic carboxylation of unsaturated hydrocarbons: whether the nature of a reductant may determine the mechanism of CO2 incorporation?

    OpenAIRE

    Kirillov, E.; Carpentier, J.-F.; Bunel, E

    2015-01-01

    International audience Application of CO2 as a renewable feedstock and C1 building block for prodn. of commodity and fine chems. is a highly challenging but obvious industry-relevant task. Of particular interest is the catalytic coupling of CO2 with inexpensive unsatd. hydrocarbons (olefins, dienes, styrenes, alkynes), providing direct access to carboxylic acids and their derivs. Although not brand new for the scientific community, it is still a complete challenge, as no truly effective ca...

  10. Calixarene based chiral solvating agents for α-hydroxy carboxylic acids

    Science.gov (United States)

    Bozkurt, Selahattin

    2013-09-01

    Novel chiral calix[4]arene derivatives functionalized at the lower rim have been prepared from the reaction of p-tert-butylcalix[4]arene diamine derivative with N-Phthaloyl-L-phenylalanine or (2S)-2-((benzyloxy)carbonyl)amino)-3-hydroxypropanoic acid or (2S,3R)-2-((benzyloxy)carbonyl)amino-3-hydroxybutanoic acid in 63-81% yield. The structures of these receptors were characterized by FTIR, 1H, 13C and 2D COSY NMR spectroscopy. The enantioselective recognition of these receptors towards the enantiomers of racemic carboxylic acids was studied by 1H NMR spectroscopy. The molar ratios of the chiral compounds with each of the enantiomers of guests were determined by using Job plots. The Job plots indicate that the hosts form 1:2 instantaneous complexes with all guests. The receptors exhibited different chiral recognition abilities toward the enantiomers of racemic guests. NMR studies demonstrated that the receptors function as highly effective chiral shift reagents for determining the enantiomeric purity of a series of carboxylic acids.

  11. 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. PMID:26453854

  12. 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.

  13. 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

    in methanol. Two different perfluorinated carboxylic acids, heptafluorobutanoic acid (HFBA) and nonafluoropentanoic acid (NFPA), were used as ion-pairing agents in the separation. The selectivities of the ion-pairing agents were different. The separation was performed on a microbore column, which...

  14. 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.

  15. Effect of A Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A SANS Study

    Science.gov (United States)

    Patriati, Arum; Giri Rachman Putra, Edy; Seok Seong, Baek

    2010-01-01

    The effect of a different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH3(CH)10COOH or lauric acid and hexadecanoic acid, CH3(CH2)14COOH or palmitic acid as a co-surfactant in the 0.3 M sodium dedecyl sulfate, SDS micellar solution has been studied using small angle neutron scattering (SANS). The present of lauric acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 22.6 Å to 37.1 Å at a fixed minor axis of 16.7 Å in the present of 0.005 M to 0.1 M lauric acid. Nevertheless, this effect did not occur in the present of palmitic acid with the same concentration range. The present of palmitic acid molecules performed insignificant effect on the SDS micelles growth where the major axis of the micelle was elongated from 22.9 Å to 25.3 Å only. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules emerged as one of the determining factors in forming a mixed micelles structure.

  16. Visible-Light-Induced Decarboxylative Functionalization of Carboxylic Acids and Their Derivatives.

    Science.gov (United States)

    Xuan, Jun; Zhang, Zhao-Guo; Xiao, Wen-Jing

    2015-12-21

    Visible-light-induced radical decarboxylative functionalization of carboxylic acids and their derivatives has recently received considerable attention as a novel and efficient method to create CC and CX bonds. Generally, this visible-light-promoted decarboxylation process can smoothly occur under mild reaction conditions with a broad range of substrates and an excellent functional-group tolerance. The radical species formed from the decarboxylation step can participate in not only single photocatalytic transformations, but also dual-catalytic cross-coupling reactions by combining photoredox catalysis with other catalytic processes. Recent advances in this research area are discussed herein. PMID:26509837

  17. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    OpenAIRE

    Isabel Bento; Teresa Duarte, M.; M. João M. Curto; Inês F. Antunes; Hélène Ramos; Fátima C. Teixeira

    2006-01-01

    A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2)nCO2R of different lengths (n = 0-6, 9, 10) are described.Nucleophilic substitution reactions on halo esters (X(CH2)nCO2R) by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultin...

  18. The First General Electron Transfer Reductions of Carboxylic Acid Derivatives Using Samarium Diiodide

    OpenAIRE

    Spain, Malcolm Peter

    2014-01-01

    The development of new methods for the reduction of carboxylic acid derivatives is described. The ability to reduce these carbonyl derivatives through radical intermediates provides an orthogonal approach as compared with hydride based reductions.Initial experiments focused on the development of the SmI2–H2O system, where we have shown that chelation effects can be utilised to facilitate reduction of cyclic esters. Furthermore, a revised mechanism for the SmI2–H2O mediated reduction of lacton...

  19. 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

    Polyethylene glycols (PEGs) are attractive as excipients in the manufacture of drug products because they are water soluble and poorly immunogenic. They are used in various pharmaceutical preparations. However, because of their terminal hydroxyl groups, PEGs can participate in esterification...... 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...

  20. Carboxylic Acid Photochemistry is a Marine Source of Glyoxal and Other Aldehydes

    Science.gov (United States)

    Chiu, R.; Gonzalez, L.; Tinel, L.; George, C.; Volkamer, R. M.

    2015-12-01

    Glyoxal is a highly water-soluble precursor in secondary organic aerosol (SOA) formation. Over land, glyoxal is known to be produced by the oxidation of volatile organic carbon (VOC) from both anthropogenic and natural sources. However, marine sources are still not well understood. Previous studies above the remote Pacific Ocean have detected typical glyoxal mixing ratios of 30-40 pptv, concentrations too high to be explained with current chemical understanding or atmospheric models. Because the lifetime of glyoxal is very short, the glyoxal found must have originated from, rather than been transported to, the open ocean. Furthermore, eddy covariance measurements indicate that an organic surface microlayer may be producing the glyoxal by as yet unknown processes. Here we present laboratory studies of the formation of glyoxal from carboxylic acids. Nonanoic, octanoic, and heptanoic acids floated on water and subjected to ultraviolet light are converted into their equivalent alkenals. Subsequent ozonolysis of the alkenals leads to the formation of glyoxal. We employ a PTR-MS to detect the alkenals, and a cavity-enhanced DOAS to detect the glyoxal. Considering the ubiquitous occurrence of carboxylic acids and their derivatives in the environment, this mechanism has the potential to be a significant source of glyoxal in the atmosphere.

  1. Self-assembly of indole-2-carboxylic acid at graphite and gold surfaces

    Science.gov (United States)

    De Marchi, Fabrizio; Cui, Daling; Lipton-Duffin, Josh; Santato, Clara; MacLeod, Jennifer M.; Rosei, Federico

    2015-03-01

    Model systems are critical to our understanding of self-assembly processes. As such, we have studied the surface self-assembly of a small and simple molecule, indole-2-carboxylic acid (I2CA). We combine density functional theory gas-phase (DFT) calculations with scanning tunneling microscopy to reveal details of I2CA assembly in two different solvents at the solution/solid interface, and on Au(111) in ultrahigh vacuum (UHV). In UHV and at the trichlorobenzene/highly oriented pyrolytic graphite (HOPG) interface, I2CA forms epitaxial lamellar structures based on cyclic OH⋯O carboxylic dimers. The structure formed at the heptanoic acid/HOPG interface is different and can be interpreted in a model where heptanoic acid molecules co-adsorb on the substrate with the I2CA, forming a bicomponent commensurate unit cell. DFT calculations of dimer energetics elucidate the basic building blocks of these structures, whereas calculations of periodic two-dimensional assemblies reveal the epitaxial effects introduced by the different substrates.

  2. Fluorescence of complexes of Eu( Ⅱ ) with aromatic carboxylic acid-1, 1O-phenanthroline

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The 1, 10-phenanthroline-aromatic carboxylic acid (benzoic acid and o-phthalic acid) binary and ternary complexes of europium were synthesized. The fluorescence and FT-IR spectroscopy, elemental analysis, UV spectroscopic studies on these complexes were also performed. These complexes can emit strong red fluorescence of Eu( m ) excited by UV light. At the same excited wavelength, the fluorescence spectra of the complexes were also studied. The results indi cated that the fluorescence intensities of ternary complexes are stronger than that of binary complexes. The reason is that phenanthroline has higher electron density and higher orbit scope in the conjugated system and consequently an easier ener gy transfer to the europium ion, which makes the fluorescence intensity of ternary complexes be stronger than that of bi nary complexes.

  3. 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.

  4. Occurrence of carboxylic acids in different steps of two drinking-water treatment plants using different disinfectants.

    Science.gov (United States)

    Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

    2014-03-15

    The occurrence of 35 aliphatic and aromatic carboxylic acids within two full scale drinking-water treatment plants was evaluated for the first time in this research. At the intake of each plant (raw water), the occurrence of carboxylic acids varied according to the quality of the water source although in both cases 13 acids were detected at average concentrations of 6.9 and 4.7 μg/L (in winter). In the following steps in each treatment plant, the concentration patterns of these compounds differed depending on the type of disinfectant applied. Thus, after disinfection by chloramination, the levels of the acids remained almost constant (average concentration, 6.3 μg/L) and four new acids were formed (butyric, 2-methylbutyric, 3-hydroxybenzoic and 2-nitrobenzoic) at low levels (1.1-5 μg/L). When ozonation/chlorination was used, the total concentration of the carboxylic acids in the raw water sample (4.7 μg/L) increased up to 6 times (average concentration, 26.3 μg/L) after disinfection and 6 new acids (mainly aromatic) were produced at high levels (3.5-100 μg/L). Seasonal variations of the carboxylic acids under study showed that in both plants, maximum levels of all the analytes were reached in the coldest months (autumn and winter), aromatic acids only being found in those seasons.

  5. Biomimetic Decarboxylation of Carboxylic Acids with PhI(OAc)2 Catalyzed by Manganese Porphyrin [Mn(TPP)OAcl

    Institute of Scientific and Technical Information of China (English)

    GHOLAM REZA Karimipour; ROXANA Ahmadpour

    2008-01-01

    Manganese(Ⅲ) meso-tetraphenylporphyrin acetate [Mn(TPP)OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with (diacetoxyiodo)benzene [Phl(OAc)2] in CH2C12-H2O(95:5,volume ratio),The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn(TPP)OAc,In the former case,the formation of carbonyl products was complete within just a few minutes with >97% selectivities,and no further oxidation of the produced aldehydes was achieved under these catalytic conditions,This method provides a benign procedure owing to the utilization of low toxic(diacetoxyiodo)benzene,biologically relevant manganese porphyrins,and carboxylic acids.

  6. Penarines A-F, (nor-)sesquiterpene carboxylic acids from Hygrophorus penarius (Basidiomycetes).

    Science.gov (United States)

    Otto, Alexander; Porzel, Andrea; Schmidt, Jürgen; Wessjohann, Ludger; Arnold, Norbert

    2014-12-01

    Five sesquiterpene carboxylic acids (1-5) and one nor-sesquiterpene carboxylic acid (6) of the very rare ventricosane type, named penarines A-F, were isolated from fruiting bodies of the basidiomycete Hygrophorus penarius (Hygrophoraceae). This is the first report of (nor)-sesquiterpenes isolated from basidiocarps of the family Hygrophoraceae. Their structures were elucidated on the basis of extensive 1D ((1)H, (13)C) and 2D (HSQC, HMBC, COSY, ROESY) NMR spectroscopic analyses as well as high-resolution mass spectrometry studies. Additionally, the only known member of this rare type of sesquiterpenes, ventricos-7(13)-ene (7), could be identified via headspace GC-MS analysis in a fruiting body of H. penarius. Compounds 1-6 were devoid of remarkable antifungal activity against Cladosporium cucumerinum. Additionally, the cytotoxic activities of compounds 1 and 2 were evaluated against the human prostate cancer cell line PC-3 and the colon cancer cell line HT-29 showing no significant cytotoxic activity. PMID:25269661

  7. Aldehydes, ketones, and carboxylic acids formed radiolytically in aqueous solutions of cyanides and simple nitriles

    Energy Technology Data Exchange (ETDEWEB)

    Negron-Mendoza, A.; Draganic, Z.D.; Navarro-Gonzalez, R.; Graganic, I.G.

    1983-08-01

    A systematic search for aldehydes, ketones, and carboxylic acids was carried out in aqueous solutions of HCN, NH/sub 4/CN, CH/sub 3/CN, and C/sub 2/H/sub 4/CN, that had received multikilogray doses of /sup 60/Co ..gamma.. radiation. About 30 radiolytic products were identified, among them a large variety of dicarboxylic and tricarboxylic acids. Some of them might be of significant interest in molecular evolution studies of prebiotic processes. They originate in the free-radical-initiated chemical reactions where the additional oligomerization processes are particularly important. Most of the radiolytic products appear in both cyanides and nitriles and point to the importance of reactions involving the carbon-nitrogen triple bond.

  8. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Isabel Bento

    2006-11-01

    Full Text Available A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2nCO2R of different lengths (n = 0-6, 9, 10 are described.Nucleophilic substitution reactions on halo esters (X(CH2nCO2R by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds.

  9. Electrocatalytic carboxylation of chloroacetonitrile at a silver cathode for the synthesis of cyanoacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Scialdone, Onofrio [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)], E-mail: scialdone@dicpm.unipa.it; Galia, Alessandro; Filardo, Giuseppe [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Isse, Abdirisak Ahmed [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy)], E-mail: Abdirisak.ahmedisse@unipd.it; Gennaro, Armando [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy)

    2008-12-30

    The electrocatalytic carboxylation of chloroacetonitrile to cyanoacetic acid performed at silver cathodes was investigated both theoretically and experimentally. Silver exhibits powerful electrocatalytic activities towards the reduction of chloroacetonitrile. In CO{sub 2}-saturated CH{sub 3}CN, reduction of NCCH{sub 2}Cl occurs at potentials that are about 0.7 V more positive than those observed at glassy carbon and gives cyanoacetic acid in good yields. Theoretical considerations on the effect of operative parameters on the performances of the process were confirmed by electrocarboxylation experiments performed in undivided cells equipped with sacrificial anodes both in a bench-scale electrochemical batch reactor and in a continuous batch recirculation reaction system equipped with a parallel plate electrochemical cell. Selectivities and Faradic efficiencies higher than 80% were obtained by working under anhydrous conditions both under amperostatic and potentiostatic alimentation at proper values of either current density or applied potential.

  10. Structure-activity relationship of an ozonide carboxylic acid (OZ78) against Fasciola hepatica.

    Science.gov (United States)

    Zhao, Qingjie; Vargas, Mireille; Dong, Yuxiang; Zhou, Lin; Wang, Xiaofang; Sriraghavan, Kamaraj; Keiser, Jennifer; Vennerstrom, Jonathan L

    2010-05-27

    In this paper, we describe the SAR of ozonide carboxylic acid OZ78 (1) as the first part of our search for a trematocidal synthetic peroxide drug development candidate. We found that relatively small structural changes to 1 resulted most commonly in loss of activity against Fasciola hepatica in vivo. A spiroadamantane substructure and acidic functional group (or ester prodrug) were required for activity. Of 26 new compounds administered at single 100 mg/kg oral doses to F. hepatica infected rats, 8 had statistically significant worm burden reductions, 7 were partially curative, and 1 (acylsulfonamide 6) was completely curative and comparable to 1 in flukicidal efficacy. This study also showed that the activity of 1 is peroxide-bond-dependent, suggesting that its flukicidal efficacy depends upon hemoglobin digestion in F. hepatica. PMID:20423101

  11. 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.

  12. Structure–anticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives

    Directory of Open Access Journals (Sweden)

    Lesyk R. B.

    2010-04-01

    Full Text Available The aim of present research was investigation of anticancer activity of 4-azolidinone-3-carboxylic acids derivatives, and studies of structure–activity relationships (SAR aspects. Methods. Organic synthesis; spectral methods; anticancer screening was performed according to the US NCI protocol (Developmental Therapeutic Program. Results. The data of new 4-thiazolidinone-3-alkanecarboxylic acids derivatives in vitro anticancer activity were described. The most active compounds which belong to 5-arylidene-2,4- thia(imidazolidinone-3-alkanecarboxylic acids; 5-aryl(heterylidenerhodanine-3-succinic acids derivatives were selected. Determination of some SAR aspects which allowed to determine directions in lead- compounds structure optimization, as well as desirable molecular fragments for design of potential anticancer agents based on 4-azolidinone scaffold were performed. 5-Arylidenehydantoin-3-acetic acids amides were identified as a new class of significant selective antileukemic agents. Possible pharmacophore scaffold of 5-ylidenerhodanine-3-succinic acids derivatives was suggested. Conclusions. The series of active compounds with high anticancer activity and/or selectivity levels were selected. Some SAR aspects were determined and structure design directions were proposed.

  13. (Benzoato-κ2O,O′(quinoline-2-carboxylato-κ2N,O(quinoline-2-carboxylic acid-κ2N,Omanganese(II

    Directory of Open Access Journals (Sweden)

    Nuno D. Martins

    2008-01-01

    Full Text Available The crystal structure of the title compound, [Mn(C7H5O2(C10H6NO2(C10H7NO2], contains manganese(II ions six-coordinated in a distorted octahedral environment. The equatorial plane is occupied by four O atoms, two from the carboxylate group of the benzoate ion, the other two from carboxylate/carboxyl groups of the quinaldate/quinaldic acid molecules. The axial positions are occupied by the N atoms of the quinoline ring systems. The metal ion lies on a twofold rotation axis that bisects the benzoate ligand; the quinaldate and quinaldic acid ligands are therefore equivalent by symmetry, and the carboxylate/carboxyl groups are disordered. The complexes are joined together by hydrogen bonds between the carboxylate/carboxyl groups of adjacent quinaldate/quinaldic acid molecules, forming zigzag chains that run along the c axis.

  14. Effect of side chain length on intrahelical interactions between carboxylate- and guanidinium-containing amino acids.

    Science.gov (United States)

    Kuo, Hsiou-Ting; Yang, Po-An; Wang, Wei-Ren; Hsu, Hao-Chun; Wu, Cheng-Hsun; Ting, Yu-Te; Weng, Ming-Huei; Kuo, Li-Hung; Cheng, Richard P

    2014-08-01

    The charge-containing hydrophilic functionalities of encoded charged amino acids are linked to the backbone via different numbers of hydrophobic methylenes, despite the apparent electrostatic nature of protein ion pairing interactions. To investigate the effect of side chain length of guanidinium- and carboxylate-containing residues on ion pairing interactions, α-helical peptides containing Zbb-Xaa (i, i + 3), (i, i + 4) and (i, i + 5) (Zbb = carboxylate-containing residues Aad, Glu, Asp in decreasing length; Xaa = guanidinium residues Agh, Arg, Agb, Agp in decreasing length) sequence patterns were studied by circular dichroism spectroscopy (CD). The helicity of Aad- and Glu-containing peptides was similar and mostly pH independent, whereas the helicity of Asp-containing peptides was mostly pH dependent. Furthermore, the Arg-containing peptides consistently exhibited higher helicity compared to the corresponding Agp-, Agb-, and Agh-containing peptides. Side chain conformational analysis by molecular mechanics calculations showed that the Zbb-Xaa (i, i + 3) and (i, i + 4) interactions mainly involved the χ 1 dihedral combinations (g+, g+) and (g-, g+), respectively. These low energy conformations were also observed in intrahelical Asp-Arg and Glu-Arg salt bridges of natural proteins. Accordingly, Asp and Glu provides variation in helix characteristics associated with Arg, but Aad does not provide features beyond those already delivered by Glu. Importantly, nature may have chosen the side chain length of Arg to support helical conformations through inherent high helix propensity coupled with stabilizing intrahelical ion pairing interactions with the carboxylate-containing residues.

  15. The effect of aliphatic carboxylic acids on olfaction-based host-seeking of the malaria mosquito Anopheles gambiae sensu stricto

    NARCIS (Netherlands)

    Smallegange, R.C.; Qiu, Y.T.; Bukovinszkine-Kiss, G.; Loon, van J.J.A.; Takken, W.

    2009-01-01

    The role of aliphatic carboxylic acids in host-seeking response of the malaria mosquito Anopheles gambiae sensu stricto was examined both in a dual-choice olfactometer and with indoor traps. A basic attractive blend of ammonia + lactic acid served as internal standard odor. Single carboxylic acids w

  16. Influence of cyclic dimer formation on the phase behavior of carboxylic acids. II. Cross-associating systems.

    Science.gov (United States)

    Janeček, Jiří; Paricaud, Patrice

    2013-08-15

    The doubly bonded dimer association scheme (DBD) proposed by Sear and Jackson is extended to mixtures exhibiting both self- and cross-associations. The PC-SAFT equation of state is combined with the new DBD association contribution to describe the vapor-liquid equilibria of binary mixtures of carboxylic acids + associating compounds (water, alcohols, and carboxylic acids). The effect of doubly bonded dimers on the phase behavior in such systems is less important than in mixtures of carboxylic acids with nonassociating compounds, due to the cross-associations that compete with the formation of DBDs. Nevertheless, a clear improvement in the description of vapor-liquid coexistence curves is achieved over the classical 2B association model, particularly for the dew point curves.

  17. Microbiologically produced carboxylic acids used as building blocks in organic synthesis.

    Science.gov (United States)

    Aurich, Andreas; Specht, Robert; Müller, Roland A; Stottmeister, Ulrich; Yovkova, Venelina; Otto, Christina; Holz, Martina; Barth, Gerold; Heretsch, Philipp; Thomas, Franziska A; Sicker, Dieter; Giannis, Athanassios

    2012-01-01

    Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building blocks. Thereby, our biotechnological goal was the development of process fundamentals regarding the variable use of renewable raw materials, the development of a multi purpose bioreactor and application of a pilot plant with standard equipment for organic acid production to minimize the technological effort. Furthermore the development of new product isolation procedures, with the aim of direct product recovery, capture of products or single step operation, was necessary. The application of robust and approved microorganisms, also genetically modified, capable of using a wide range of substrates as well as producing a large spectrum of products, was of special importance. Microbiologically produced acids, like 2-oxo-glutaric acid and 2-oxo-D-gluconic acid, are useful educts for the chemical synthesis of hydrophilic triazines, spiro-connected heterocycles, benzotriazines, and pyranoic amino acids. The chiral intermediate of the tricarboxylic acid cycle, (2R,3S)-isocitric acid, is another promising compound. For the first time our process provides large quantities of enantiopure trimethyl (2R,3S)-isocitrate which was used in subsequent chemical transformations to provide new chiral entities for further usage in total synthesis and pharmaceutical research.Oxo- and hydroxy-carboxylic acids are of special interest in organic synthesis. However, their introduction by chemical reactions tends to be troublesome especially with regard to stereoselectivity. We describe herein the biotechnological preparation of selected oxo- and hydroxycarboxylic acids under "green" conditions and their use as promising new building

  18. 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.

  19. Benzyl esters of C2-C20 fatty acids and metabolically relevant carboxylic acids. Preparation and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Schatowitz, B; Gercken, G

    1987-11-13

    Short-, medium- and long-chain fatty acids, and other types of metabolically relevant carboxylic acids like hydroxy-, keto-, aromatic and dicarboxylic acids, were analyzed by capillary gas chromatography. For separation, benzyl ester derivatives were used, prepared by reaction of the potassium carboxylates with benzyl bromide in acetonitrile catalyzed by a crown ether. The reaction conditions for quantitative benzylation were studied. Keto groups of ketocarboxylic acids were stabilized prior to benzylation by formation of O-methyl oximes using methoxyamine hydrochloride in aqueous-ethanolic solution. The separation of more than 45 carboxylic acids was achieved on a CP-Sil 5 CB fused-silica capillary column in less than 70 min. The electron impact mass spectra of ketocarboxylic acid O-methyl oxime benzyl esters PMID:3693495

  20. 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. PMID:27057092

  1. 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.

  2. 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.

  3. Anti-cancer evaluation of carboxamides of furano-sesquiterpene carboxylic acids from the soft coral Sinularia kavarattiensis.

    Science.gov (United States)

    Rajaram, Singanaboina; Ramulu, Udugu; Ramesh, Dasari; Srikanth, Dudem; Bhattacharya, Papri; Prabhakar, Peddikotla; Kalivendi, Shasi V; Babu, Katragadda Suresh; Venkateswarlu, Yenamandra; Navath, Suryakiran

    2013-12-01

    The chemical investigation of soft coral Sinularia kavarattiensis is described. It yielded furano-sesquiterpene carboxylic acids 1 and 2 and their methyl esters 3 and 4. Semi-synthesis of furano-sesquiterpene carboxylic acid 1 gave amide derivatives 5-12. Structures of all the compounds were established by IR, NMR and mass spectral analysis. Interestingly all compounds are selectively potent on leukemia cell line. All these compounds were screened for cytotoxic activity against five human cancer cell lines (leukemia, prostate, lung, breast and cervix). Among these compounds 9 and 10 showed promising activity against leukemia and prostate cancer cell lines. PMID:24144848

  4. Iron-Catalyzed, Highly Regioselective Synthesis of alpha-Aryl Carboxylic Acids from Styrene Derivatives and CO2

    OpenAIRE

    Greenhalgh, Mark D.; Thomas, Stephen P.

    2012-01-01

    The iron-catalyzed hydrocarboxylation of aryl alkenes has been developed using a highly active bench-stable iron(II) precatalyst to give alpha-aryl carboxylic acids in excellent yields and with near-perfect regioselectivity. Using just 1 mol % FeCl2, bis(imino)pyridine 6 (1 mol %), CO2 (atmospheric pressure), and a hydride source (EtMgBr, 1.2 equiv), a range of sterically and electronically differentiated aryl alkenes were transformed to the corresponding alpha-aryl carboxylic acids (up to 96...

  5. Synthesis and Transformations of di-endo-3-Aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Márta Palkó

    2011-09-01

    Full Text Available all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13 and all-endo-5-amino-6-(hydroxymethylbicyclo[2.2.2]octan-2-ol (10 were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2. Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR.

  6. Iodine-Catalyzed Decarboxylative Amidation of β,γ-Unsaturated Carboxylic Acids with Chloramine Salts Leading to Allylic Amides.

    Science.gov (United States)

    Kiyokawa, Kensuke; Kojima, Takumi; Hishikawa, Yusuke; Minakata, Satoshi

    2015-10-26

    The iodine-catalyzed decarboxylative amidation of β,γ-unsaturated carboxylic acids with chloramine salts is described. This method enables the regioselective synthesis of allylic amides from various types of β,γ-unsaturated carboxylic acids containing substituents at the α- and β-positions. In the reaction, N-iodo-N-chloroamides, generated by the reaction of a chloramine salt with I2 , function as a key active species. The reaction provides an attractive alternative to existing methods for the synthesis of useful secondary allylic amine derivatives. PMID:26493878

  7. Synthesis, structural characterization and antimicrobial activities of diorganotin(IV) complexes with azo-imino carboxylic acid ligand: Crystal structure and topological study of a doubly phenoxide-bridged dimeric dimethyltin(IV) complex appended with free carboxylic acid groups

    Science.gov (United States)

    Roy, Manojit; Roy, Subhadip; Devi, N. Manglembi; Singh, Ch. Brajakishor; Singh, Keisham Surjit

    2016-09-01

    Diorganotin(IV) complexes appended with free carboxylic acids were synthesized by reacting diorganotin(IV) dichlorides [R2SnCl2; R = Me (1), Bu (2) and Ph (3)] with an azo-imino carboxylic acid ligand i.e. 2-{4-hydroxy-3-[(2-hydroxyphenylimino)methyl]phenylazo}benzoic acid in presence of triethylamine. The complexes were characterized by elemental analysis, IR and multinuclear NMR (1H, 13C and 119Sn) spectroscopy. The structure of 1 in solid state has been determined by X-ray crystallography. Crystal structure of 1 reveals that the compound crystallizes in monoclinic space group P21/c and is a dimeric dimethyltin(IV) complex appended with free carboxylic acid groups. In the structure of 1, the Sn(IV) atoms are hexacoordinated and have a distorted octahedral coordination geometry in which two phenoxy oxygen atoms and the azomethine nitrogen atom of the ligand coordinate to each tin atom. One of the phenoxy oxygen atom bridges the two tin centers resulting in a planar Sn2O2 core. Topological analysis is used for the description of molecular packing in 1. Tin NMR spectroscopy study indicates that the complexes have five coordinate geometry around tin atom in solution state. Since the complexes have free carboxylic acids, these compounds could be further used as potential metallo-ligands for the synthesis of other complexes. The synthesized diorganotin(IV) complexes were also screened for their antimicrobial activities and compound 2 showed effective antimicrobial activities.

  8. Different carboxylic acid homodimers in self-assemblies of adducts of 3-carboxyphenoxyacetic acid with nitrogen containing compounds

    Indian Academy of Sciences (India)

    KRAPA SHANKAR; JUBARAJ B BARUAH

    2016-05-01

    Different hydrogen bonded dimeric motifs of 3-carboxyphenoxyacetic acid (H2cpa) observed inthe self-assemblies of salts or cocrystals of H2cpa with nitrogen containing compounds are discussed. Pyridiniumsalt of the H2cpa is a self-assembly of Hcpa with the pyridinium cation. The assembly is a combinationof sub-assemblies of two Hcp anions with two pyridinium cations, in which the Hcpa cations are interconnectedthrough carboxylate-carboxylic acid interactions. The cocrystals of H2cpa with isoquinoline or isonicotinamideare self-assemblies of hydrogen bonded dimers of H2cpa holding the respective guest molecule.However, the dimeric assemblies of H2cpa in these two cases are different from each other; the former cocrystalhas carbony-hydroxyl type interactions in it whereas the latter cocrystal has unconventional dimeric subassembliesof H2cpa with hydroxyl-hydroxyl type hydrogen bond interactions. The cocrystal of H2cpa withtheophylline has sub-assemblies of two H2cpa molecules interacting with two theophylline guest molecules,where the theophylline molecules are hydrogen bonded in two different ways.

  9. 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.

  10. Polymorphism in Self-Assembled Structures of 9-Anthracene Carboxylic Acid on Ag(111

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2012-06-01

    Full Text Available Surface self-assembly process of 9-anthracene carboxylic acid (AnCA on Ag(111 was investigated using STM. Depending on the molecular surface density, four spontaneously formed and one annealed AnCA ordered phases were observed, namely a straight belt phase, a zigzag double-belt phase, two simpler dimer phases, and a kagome phase. The two high-density belt phases possess large unit cells on the scale length of 10 nm, which are seldom observed in molecular self-assembled structures. This structural diversity stems from a complicated competition of different interactions of AnCA molecules on metal surface, including intermolecular and molecular-substrate interactions, as well as the steric demand from high molecular surface density.

  11. 2-[3-Cyano-4-(2-methylpropoxyphenyl]-4-methylthiazole-5-carboxylic acid pyridine solvate

    Directory of Open Access Journals (Sweden)

    Xiong Zhu

    2009-11-01

    Full Text Available In the title compound, C16H16N2O3S·C5H5N, the benzene and thiazole rings of the Febuxostat [2-(3-cyano-4-isobutyloxyphenyl-4-methyl-5-thiazolecarboxylic acid] molecule are almost coplanar [dihedral angle = 2.4 (1°]. The carboxyl group is coplanar with the thiazole ring [O—C—C—C and O—C—C—S torsion angles of −0.7 (4 and 0.6 (3°, respectively]. The pyridine molecule of crystallization is linked to the Febuxostat molecule through an O—H...N hydrogen bond. A weak π–π stacking interaction is observed between the benzene ring of the Febuxostat molecule and pyridine molecule, with a centroid–centroid distance of 3.7530 (18 Å.

  12. Probing the orthosteric binding site of GABAA receptors with heterocyclic GABA carboxylic acid bioisosteres

    DEFF Research Database (Denmark)

    Petersen, Jette G; Bergmann, Rikke; Krogsgaard-Larsen, Povl;

    2013-01-01

    the orthosteric binding site. The physicochemical properties of the heterocyclic moieties making them suitable for bioisosteric replacement of the carboxylic acid in the molecule of GABA are discussed. A variety of synthetic strategies for synthesis of the heterocyclic scaffolds are available. Likewise, methods...... for introduction of substituents into specific positions of the heterocyclic scaffolds facilitate the investigation of different regions in the orthosteric binding pocket in close vicinity of the core scaffolds of muscimol/GABA. The development of structural models, from pharmacophore models to receptor homology...... models, has provided more insight into the molecular basis for binding. Similar binding modes are proposed for the heterocyclic GABA analogues covered in this review by use of ligand-receptor docking into the receptor homology model and the presented structure-activity relationships. A network...

  13. Electrochemiluminescence Study of Europium (III Complex with Coumarin3-Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Stefan Lis

    2008-01-01

    Full Text Available The europium (III complex of coumarin-3-carboxylic acid (C3CA has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence spectroscopy. The synthesised complex having a formula Eu(C3CA2(NO3(H2O2 was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET in the generated ECL.

  14. Isolation and Molecular Characterization of 1-Aminocyclopropane-1-carboxylic Acid Synthase Genes in Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Jia-Hong Zhu

    2015-02-01

    Full Text Available Ethylene is an important factor that stimulates Hevea brasiliensis to produce natural rubber. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS is a rate-limiting enzyme in ethylene biosynthesis. However, knowledge of the ACS gene family of H. brasiliensis is limited. In this study, nine ACS-like genes were identified in H. brasiliensis. Sequence and phylogenetic analysis results confirmed that seven isozymes (HbACS1–7 of these nine ACS-like genes were similar to ACS isozymes with ACS activity in other plants. Expression analysis results showed that seven ACS genes were differentially expressed in roots, barks, flowers, and leaves of H. brasiliensis. However, no or low ACS gene expression was detected in the latex of H. brasiliensis. Moreover, seven genes were differentially up-regulated by ethylene treatment. These results provided relevant information to help determine the functions of the ACS gene in H. brasiliensis, particularly the functions in regulating ethylene stimulation of latex production.

  15. 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

  16. Metallaphotoredox-catalysed sp(3)-sp(3) cross-coupling of carboxylic acids with alkyl halides.

    Science.gov (United States)

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

    2016-08-18

    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 sp(3)-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 sp(2)-hybridized species, the development of methods for sp(3)-sp(3) 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 sp(3)-sp(3) 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 sp(3)-sp(3) 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 sp(3)-sp(3) bonds using only simple carboxylic acids and alkyl halides as the nucleophilic and electrophilic coupling partners, respectively. This metallaphotoredox

  17. Synthesis and Antitumor Activity of 17-carboxylic acid M odified A mide D erivatives of 3-hydroxy betulinic acid

    Directory of Open Access Journals (Sweden)

    Yi Bi

    2013-08-01

    Full Text Available A novel series of 17-carboxylic acid modified amide derivatives of 3-hydroxy betulinic acid (1 were prepared and tested in vitro against five cell lines: A549 (human lung carcinoma, BEL-7402 (human hepatoma, SF-763 (human cerebroma, B16 (mice melanoma and HL-60 (human leukaemia . Within this series of compounds, 4a (IC 50=21.08 μ M in SF-763, IC 50=21.63 μ M in HL-60, 4b (IC 50=28.45 μ M in HL-60,IC 50=29.32 μ M in BEL-7402 and 6g (IC 50=26.09 μM in BEL-7402, IC 50=22.65 μM in HL-60 have the mo re potent cytotoxic activity than lead compound 1. The preliminary structure-activity relationship analysis of the C-28 amide derivatives is also discussed.

  18. 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

    2013-01-01

    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.

  19. 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. PMID:26898679

  20. Effect of Concentration of Structurally-Different Carboxylic Acids on Growth and Aggregation of Calcium Oxalate in Gel Systems

    Institute of Scientific and Technical Information of China (English)

    DENG,Sui-Ping; OUYANG,Jian-Ming

    2007-01-01

    The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid (H4edta), citric acid (H3cit), tartaric acid (H2tart), and acetic acid (HOAc) on growth and aggregation of calcium oxalate (CaOxa) in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of calcium oxalate monohydrate (COM) and induce the formation of calcium oxalate dihydrate (COD). H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order: H4edta>H3cit>H2tart>>HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.

  1. 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.

  2. Production and Characterization of Activated Carbon from Oil-Palm Shell for Carboxylic Acid Adsorption

    Directory of Open Access Journals (Sweden)

    Hector Ruiz

    2015-06-01

    Full Text Available In this study, the recovery of volatile carboxylic acids (VCA by adsorption onto activated carbon adsorbent (CA was explored. The CA was synthesized from palm-oil kernel shells using H3PO4 at 10 and 60% w/w as activating agent. The samples produced in this manner were labeled as CA10A, CA60A respectively. Also KOH was used as activating agent at 10 and 60% w/w. In this case, the produced samples were labeled as CA10B, CA60B respectively. After activation, the surface of all four CA samples was extensively characterized both physically and chemically. The obtained CA adsorption behavior for VCA was assessed by submerging samples of CA in solutions at a fixed initial VCA concentration. Because some of the acids were adsorbed on the CA surface, the VCA concentration in solution was reduced. Carbon CA60B exhibited the greatest adsorption capacity, reaching 1300 mg of adsorbed acids/g carbon. Five adsorption isotherms models were fitted to experimental data. The Langmuir-Freundlich model described best the adsorption phenomena. Desorption behavior was assessed by placing CA after adsorption in water and was not high, which forces to reconsider either de desorption mechanism proposed in this study and/or the use CA as synthesized here for VCA recovery.

  3. Radioimmunoassay for anileridine, meperidine, and other N-substituted phenylpiperidine carboxylic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Van Vunakis, H.; Freeman, D.S.; Gjika, H.B.

    1975-10-01

    Antibodies that bind an /sup 125/I-tyramyl derivative of N-succinylanileridine have been produced in animals immunized with N-succinylanileridine-hemocyanin conjugate. Several congeners and metabolites have been tested as competitors of this antigen-antibody reaction. The concentrations (in picomoles) required for 50 percent inhibition have been found to be: anileridine (0.2), meperidine (3.5), piminodine (3.8), diphenoxylate (20.5), normeperidine (20.0), meperidine acid (45,000) and anileridine acid (3,400). Although ester hydrolysis results in changes in inhibiting capacities on the order of 10/sup 4/, major structural changes in the substituent on the nitrogen of the piperidine ring are not readily recognized by the antibody. This radioimmunoassay can be used to study a variety of N-substituted phenylpiperidine carboxylic acid esters by relating the results to the standard curve obtained for the drug under investigation. For all practical purposes, alphaprodine, morphine and methadone do not interfere with the assay.

  4. Radioimmunoassay for anileridine, meperidine, and other N-substituted phenylpiperidine carboxylic acid esters

    International Nuclear Information System (INIS)

    Antibodies that bind an 125I-tyramyl derivative of N-succinylanileridine have been produced in animals immunized with N-succinylanileridine-hemocyanin conjugate. Several congeners and metabolites have been tested as competitors of this antigen-antibody reaction. The concentrations (in picomoles) required for 50 percent inhibition have been found to be: anileridine (0.2), meperidine (3.5), piminodine (3.8), diphenoxylate (20.5), normeperidine (20.0), meperidine acid (45,000) and anileridine acid (3,400). Although ester hydrolysis results in changes in inhibiting capacities on the order of 104, major structural changes in the substituent on the nitrogen of the piperidine ring are not readily recognized by the antibody. This radioimmunoassay can be used to study a variety of N-substituted phenylpiperidine carboxylic acid esters by relating the results to the standard curve obtained for the drug under investigation. For all practical purposes, alphaprodine, morphine and methadone do not interfere with the assay

  5. 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 t

  6. Selective preparation of terminal alkenes from aliphatic carboxylic acids by a palladium-catalysed decarbonylation-eliminiation reaction

    NARCIS (Netherlands)

    Notre, le J.E.L.; Scott, E.L.; Franssen, M.C.R.; Sanders, J.P.M.

    2010-01-01

    Trialkylamines were used as additives in the decarbonylation–elimination reaction catalysed by the combination of palladium(II) chloride and DPE-Phos. Aliphatic carboxylic acids were transformed at relatively low temperature into terminal alkenes in high yield and high selectivity, without the need

  7. 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...

  8. Design, Synthesis and Anti-HIV Integrase Evaluation of 4-Oxo-4H-quinolizine-3-carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Li-Ming Hu

    2009-02-01

    Full Text Available 4-Oxo-4H-quinolizine-3-carboxylic acid derivatives bearing sulfamido, carboxylamido, benzimidazole and benzothiazole substituents have been designed and synthesized. The structures of these new compounds were confirmed by 1H-NMR, 13C- NMR, IR and ESI (or HRMS spectra. Compounds were screened for possible HIV integrase inhibitory activity.

  9. 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.

  10. Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

    Directory of Open Access Journals (Sweden)

    Robert J. Perkins

    2013-08-01

    Full Text Available Carboxylic acids have been electro-oxidatively coupled to electron-rich olefins to form lactones. Kolbe decarboxylation does not appear to be a significant competing pathway. Experimental results indicate that oxidation occurs at the olefin and that the reaction proceeds through a radical cation intermediate.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Se Hee; Lim, Jin Woo; Yu, Jin; Kim, Jae Nyoung [Chonnam National Univ., Gwangju (Korea, Republic of)

    2013-09-15

    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.

  12. 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...... of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste...

  13. Alkaline battery containing a separator of a cross-linked copolymer of vinyl alcohol and unsaturated carboxylic acid

    Science.gov (United States)

    Hsu, L. C.; Philipp, W. H.; Sheibley, D. W.; Gonzalez-Sanabria, O. D. (Inventor)

    1985-01-01

    A battery separator for an alkaline battery is described. The separator comprises a cross linked copolymer of vinyl alcohol units and unsaturated carboxylic acid units. The cross linked copolymer is insoluble in water, has excellent zincate diffusion and oxygen gas barrier properties and a low electrical resistivity. Cross linking with a polyaldehyde cross linking agent is preferred.

  14. An atom-economic approach to carboxylic acids via Pd-catalyzed direct addition of formic acid to olefins with acetic anhydride as a co-catalyst.

    Science.gov (United States)

    Wang, Yang; Ren, Wenlong; Shi, Yian

    2015-08-21

    An effective Pd-catalyzed hydrocarboxylation of olefins using formic acid with acetic anhydride as a co-catalyst is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under mild reaction conditions without the use of toxic CO gas.

  15. In vitro assessment of potential intestinal absorption of some phenolic families and carboxylic acids from commercial instant coffee samples.

    Science.gov (United States)

    López-Froilán, R; Ramírez-Moreno, E; Podio, N S; Pérez-Rodríguez, M L; Cámara, M; Baroni, M V; Wunderlin, D A; Sánchez-Mata, M C

    2016-06-15

    Coffee is one of the most consumed beverages in the world, being a source of bioactive compounds as well as flavors. Hydroxycinnamic acids, flavonols, and carboxylic acids have been studied in the samples of instant coffee commercialized in Spain. The studies about contents of food components should be complemented with either in vitro or in vivo bioaccessibility studies to know the amount of food components effectively available for functions in the human body. In this sense, a widely used in vitro model has been applied to assess the potential intestinal absorption of phenolic compounds and organic acids. The contents of hydroxycinnamic acids and flavonols were higher in instant regular coffee samples than in the decaffeinated ones. Bioaccessible phenolic compounds in most analyzed samples account for 20-25% of hydroxycinnamic acids and 17-26% of flavonols. This could mean that a great part of them can remain in the gut, acting as potential in situ antioxidants. Quinic, acetic, pyroglutamic, citric and fumaric acids were identified in commercial instant coffee samples. Succinic acid was found in the coffee blend containing chicory. All carboxylic acids showed a very high bioaccessibility. Particularly, acetic acid and quinic acid were found in higher contents in the samples treated with the in vitro simulation of gastrointestinal processes, compared to the original ones, which can be explained by their cleavage from chlorogenic acid during digestion. This is considered as a positive effect, since quinic acid is considered as an antioxidant inducer. PMID:27191052

  16. Esters of o- and m-carborane-C-carboxylic acids with o- and m-C-carborane alcohols

    International Nuclear Information System (INIS)

    Acid chlorides of o- and m-carborane-C-carboxylic acids reacted with primary o- and m-C-carborane alcohols in anhydrous benzene to form in a high yield (81-86%) previously unknown corresponding o- and m-carborane-containing two- and three-nuclear esters. The composition and structure of the compounds prepared have been characterized by elementary analysis, 1H and 11B NMR, IR and UV spectroscopy, by measuring their molecular weights and melting points

  17. Application of the Organic Photosensitizers Bearing Two Carboxylic Acid Groups to Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-Hua; YAO Yi-Shan; LI Chao; WANG Wei-Bo; CHENG Xue-Xin; WANG Xue-Song; ZHANG Bao-Wen

    2008-01-01

    Three electron donor-n bridge-electron acceptor(D-π-A)organic dyes bearing two carboxylic acid groups were applied to dye-sensitized solar cells(DSSC)as sensitizers,in Which one triphenylamine or modified triphenylamine and two rhodanine-3-acetic acid fragments act as D and A.respectively.It was found that the introduction of t-butyl or methoxy group in the triphenylamine subunit could lead to more efficient photoinduced intramolecular charge transfer,thus improving the overall photoelectric conversion efficiency of the resultant DSSC.Under global AM 1.5 solar irradiation(73 mW·cm-2),the dye molecule based on methoxy-substituted triphenylamine achieved the best photovoltaic performance:a short circuit photocurrent density(Jsc)of 12.63 mA·cm-2,an open circuit voltage(Voc)of 0.55 V,a fill factor(FF)of 0.62,corresponding to an overall efficiency(η)of 5.9%.

  18. 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.

  19. The cysteine releasing pattern of some antioxidant thiazolidine-4-carboxylic acids.

    Science.gov (United States)

    Önen Bayram, F Esra; Sipahi, Hande; Acar, Ebru Türköz; Kahveci Ulugöl, Reyhan; Buran, Kerem; Akgün, Hülya

    2016-05-23

    Oxidative stress that corresponds to a significant increase in free radical concentration in cells can cause considerable damage to crucial biological macromolecules if not prevented by cellular defense mechanisms. The low-molecular-weight thiol glutathione (GSH) constitutes one of the main intracellular antioxidants. It is synthesized via cysteine, an amino acid found only in limited amounts in cells because of its neurotoxicity. Thus, to ensure an efficient GSH synthesis in case of an oxidative stress, cysteine should be provided extracellularly. Yet, given its nucleophilic properties and its rapid conversion into cystine, its corresponding disulfide, cysteine presents some toxicity and therefore is usually supplemented in a prodrug approach. Here, some thiazolidine-4-carboxylic acids were synthesized and evaluated for their antioxidant properties via the DDPH and CUPRAC assays. Then, the cysteine releasing capacity of the obtained compounds was investigated in aqueous and organic medium in order to correlate the relevant antioxidant properties of the molecules with their cysteine releasing pattern. As a result, the structures' antioxidative properties were not only attributed to cysteine release but also to the thiazolidine cycle itself. PMID:27017266

  20. Supramolecular Assemblies Using Piperazine with Dicarboxylic Acids and Hydroxy-carboxylic Acids

    Institute of Scientific and Technical Information of China (English)

    CHEN Zi-Yun; PENG Meng-Xia

    2008-01-01

    The molecular self-assembly of piperazine (pip) with 1,4-cyclohexanedicarboxylic acid (H2chda),m-phthalic acid (H2mpda),6-hydroxy-2-naphthalic acid (Hohna) and 1-hydroxy-2-naphthalic acid (Hshna) results in four new supramolecular networks formulated as H2pip·chda (1),H2pip·2Hmpda (2),HEpip·ohna·2H2O(3) and H2pip·shna (4),respectively.Single-crystal X-ray diffraction study reveals that compounds 1--3 are three-dimensional supramolecular networks,while 4 has a one-dimensional hydrogen-bonded chain-based structure,with CCDC:672051 (1),672052 (2),672053 (3) and 672054 (4).

  1. Required catalytic properties for alkane production from carboxylic acids: Hydrodeoxygenation of acetic acid

    Institute of Scientific and Technical Information of China (English)

    Zhong; He; Xianqin; Wang

    2013-01-01

    The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.

  2. 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.

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

    Science.gov (United States)

    Avdeev, Mikhail V.; Bica, Doina; Vékás, Ladislau; Marinica, Oana; Balasoiu, Maria; Aksenov, Victor L.; Rosta, László; Garamus, Vasil M.; Schreyer, Andreas

    2007-04-01

    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.

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

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. 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

    2013-01-01

    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. PMID:23248280

  7. 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.

  8. Peptide coupling between amino acids and the carboxylic acid of a functionalized chlorido-gold(I)-phosphane.

    Science.gov (United States)

    Kriechbaum, Margit; List, Manuela; Himmelsbach, Markus; Redhammer, Günther J; Monkowius, Uwe

    2014-10-01

    We have developed a protocol for the direct coupling between methyl ester protected amino acids and the chlorido-gold(I)-phosphane (p-HOOC(C6H4)PPh2)AuCl. By applying the EDC·HCl/NHS strategy (EDC·HCl = N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide hydrochloride, NHS = N-hydroxysuccinimide), the methyl esters of l-phenylalanine, glycine, l-leucine, l-alanine, and l-methionine are coupled with the carboxylic acid of the gold complex in moderate to good yields (62-88%). All amino acid tagged gold complexes were characterized by (1)H and (13)C NMR spectroscopy and high-resolution mass spectrometry. As corroborated by measurement of the angle of optical rotation, no racemization occurred during the reaction. The molecular structure of the leucine derivative was determined by single-crystal X-ray diffraction. In the course of developing an efficient coupling protocol, the acyl chlorides (p-Cl(O)C(C6H4)PPh2)AuX (X = Cl, Br) were also prepared and characterized. PMID:25203269

  9. 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. PMID:26593586

  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.

  11. Study on surface acid-base property of carboxylic acid-terminated self-assembled monolayers by cyclic voltammetry and electro-chemical impedance spectroscopy

    Institute of Scientific and Technical Information of China (English)

    罗立强; 程志亮; 杨秀荣; 汪尔康

    2000-01-01

    Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the surface acid-base property of carboxylic acid-terminated self-assembled monolayers (SAMs). A carboxylic acid-terminated thiol, such as thioctic acid (1,2-dithiolane-3-pentanoic acid), was self-assembled on gold electrodes. Electron transfer between the bulk solution and the SAM modified electrode was studied at different pH using Fe(CN)63 as a probe. The surface pK. of thioctic acid was determined by cyclic voltammetry and electrochemical impedance spectroscopy to be 5.6±0.1 and 5.8±0.1, respectively. The method is compared with other methods of monolayer pK.measurement.

  12. Jasmonic acid carboxyl methyltransferase regulates development and herbivory-induced defense response in rice.

    Science.gov (United States)

    Qi, Jinfeng; Li, Jiancai; Han, Xiu; Li, Ran; Wu, Jianqiang; Yu, Haixin; Hu, Lingfei; Xiao, Yutao; Lu, Jing; Lou, Yonggen

    2016-06-01

    Jasmonic acid (JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase (JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate (MeJA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene, OsJMT1, whose encoding protein was localized in the cytosol, we found that the recombinant OsJMT1 protein catalyzed JA to MeJA. OsJMT1 is up-regulated in response to infestation with the brown planthopper (BPH; Nilaparvata lugens). Plants in which OsJMT1 had been overexpressed (oe-JMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased MeJA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine (JA-Ile). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs, probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H2 O2 and MeJA in oe-JMT plants. These results indicate that OsJMT1, by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice. PMID:26466818

  13. A physiologically based pharmacokinetic model for quinoxaline-2-carboxylic acid in rats, extrapolation to pigs.

    Science.gov (United States)

    Yang, X; Zhou, Y-F; Yu, Y; Zhao, D-H; Shi, W; Fang, B-H; Liu, Y-H

    2015-02-01

    A multi-compartment physiologically based pharmacokinetic (PBPK) model to describe the disposition of cyadox (CYX) and its metabolite quinoxaline-2-carboxylic acid (QCA) after a single oral administration was developed in rats (200 mg/kg b.w. of CYX). Considering interspecies differences in physiology and physiochemistry, the model efficiency was validated by pharmacokinetic data set in swine. The model included six compartments that were blood, muscle, liver, kidney, adipose, and a combined compartment for the rest of tissues. The model was parameterized using rat plasma and tissue concentration data that were generated from this study. Model simulations were achieved using a commercially available software program (ACSLXL ibero version 3.0.2.1). Results supported the validity of the model with simulated tissue concentrations within the range of the observations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, adipose, and muscles in rats were 0.98, 0.98, 0.98, 0.99, and 0.95, respectively. The rat model parameters were then extrapolated to pigs to estimate QCA disposition in tissues and validated by tissue concentration of QCA in swine. The correlation coefficients between the predicted and observed values were over 0.90. This model could provide a foundation for developing more reliable pig models once more data are available.

  14. Jasmonic acid carboxyl methyltransferase regulates development and herbivory-induced defense response in rice

    Institute of Scientific and Technical Information of China (English)

    Jinfeng Qi; Yonggen Lou; Jiancai Li; Xiu Han; Ran Li; Jianqiang Wu; Haixin Yu; Lingfei Hu; Yutao Xiao; Jing Lu

    2016-01-01

    Jasmonic acid (JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase (JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate (MeJA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene, OsJMT1, whose encoding protein was localized in the cytosol, we found that the recombinant OsJMT1 protein catalyzed JA to MeJA. OsJMT1 is up-regulated in response to infestation with the brown planthopper (BPH; Nilaparvata lugens). Plants in which OsJMT1 had been overexpressed (oe-JMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased MeJA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine (JA-Ile). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs, probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H2O2 and MeJA in oe-JMT plants. These results indicate that OsJMT1, by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice.

  15. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge.

    Science.gov (United States)

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan

    2016-01-01

    Activated sludge contains complex microorganisms, which are highly effective biodegrading agents. In this study, the kinetics of biodegradation of cyclohexane carboxylic acid (CHCA) by an acclimated aerobic activated sludge were investigated. The results showed that after 180 days of acclimation, the activated sludge could steadily degrade >90% of the CHCA in 120 h. The degradation of CHCA by the acclimated activated sludge could be modeled using a first-order kinetics equation. The equations for the degradation kinetics for different initial CHCA concentrations were also obtained. The kinetics constant, kd, decreased with an increase in the CHCA concentration, indicating that, at high concentrations, CHCA had an inhibiting effect on the microorganisms in the activated sludge. The effects of pH on the degradation kinetics of CHCA were also investigated. The results showed that a pH of 10 afforded the highest degradation rate, indicating that basic conditions significantly promoted the degradation of CHCA. Moreover, it was found that the degradation efficiency for CHCA increased with an increase in temperature and concentration of dissolved oxygen under the experimental conditions.

  16. Evaluation of a series of prolylamidepyridines as the chiral derivatization reagents for enantioseparation of carboxylic acids by LC-ESI-MS/MS and the application to human saliva.

    Science.gov (United States)

    Kuwabara, Tomohiro; Takayama, Takahiro; Todoroki, Kenichiro; Inoue, Koichi; Min, Jun Zhe; Toyo'oka, Toshimasa

    2014-04-01

    Mass spectrometry has become a popular analytical tool because of its high sensitivity and specificity. The use of a chiral derivatization reagent for the mass spectrometry (MS) detection seems to be efficient for the enantiomeric separation of racemates. However, the number of chiral reagents for the liquid chromatography (LC)-MS/MS analysis is very limited. According to these observations, we are currently in the process of developing novel labeling reagents for chiral molecules in MS/MS analysis. The derivatization reagent that is effective for enhancing not only the electrospray ionization-MS/MS sensitivity but also the reversed-phase LC resolution of carboxylic acid enantiomers should have a highly proton-affinitive moiety and an asymmetric structure near the reactive functional group. Furthermore, the resulting derivative has to provide a characteristic product ion suitable for the selected reaction monitoring. Based upon these considerations, a series of prolylamidepyridines ((S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-2-yl)amide (PCP2), (S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-3-yl)amide, and (S)-N-pyrrolidine-2-carboxylic acid N-(pyridine-4-yl)amide) was synthesized as ideal labeling reagents for the enantioseparation of chiral carboxylic acids and evaluated in terms of separation efficiency and detection sensitivity by ultra-performance LC (UPLC)-MS/MS. Among the synthesized reagents, PCP2 was the most efficient chiral derivatization reagent for the enantioseparation of carboxylic acid. The Rs values and the detection limits of the derivatives of non-steroidal anti-inflammatory drugs, which were selected as the representative carboxylic acids, were in the range of 2.52-6.07 and 49-260 amol, respectively. The sensitive detection of biological carboxylic acids (detection limits, 32-520 amol) was also carried out by the proposed method using PCP2 and UPLC-MS/MS. The PCP2 was applied to the determination of carboxylic acids in human saliva. Several

  17. Carboxylic and dicarboxylic acids extracted from crushed magnesium oxide single crystals

    Science.gov (United States)

    Freund, F.; Gupta, A. D.; Kumar, D.

    1999-01-01

    Carboxylic and dicarboxylic acids (glycolic, oxalic, malonic and succinic) have been extracted with tetrahydrofuran (THF) and H2O from large synthetic MgO crystals, crushed to a medium fine powder. The extracts were characterized by infrared spectroscopy and 1H-NMR. The THF extracts were derivatized with tert-butyldimethylsilyl (t-BDMS) for GC-MS analysis. A single crystal separated from the extract was used for an x-ray structure analysis, giving the monoclinic unit cell, space group P21/c with ao = 5.543 A, bo = 8.845 A, co = 5.086 A, and beta = 91.9 degrees, consistent with beta-succinic acid, HOOC(CH2)COOH. The amount of extracted acids is estimated to be of the order of 0.1 to 0.5 mg g-1 MgO. The MgO crystals from which these organic acids were extracted grew from the 2860 degrees C hot melt, saturated with CO/CO2 and H2O, thereby incorporating small amounts of the gaseous components to form a solid solution (ss) with MgO. Upon cooling, the ss becomes supersaturated, causing solute carbon and other solute species to segregate not only to the surface but also internally, to dislocations and subgrain boundaries. The organic acids extracted from the MgO crystals after crushing appear to derive from these segregated solutes that formed C-C, C-H and C-O bonds along dislocations and other defects in the MgO structure, leading to entities that can generically be described as (HxCyOz)n-. The processes underlying the formation of these precursors are fundamental in nature and expected to be operational in any minerals, preferentially those with dense structures, that crystallized in H2O-CO2-laden environments. This opens the possibility that common magmatic and metamorphic rocks when weathering at the surface of a tectonically active planet like Earth may be an important source of abiogenically formed complex organic compounds.

  18. Distinct pathways of ERK1/2 activation by hydroxy-carboxylic acid receptor-1.

    Directory of Open Access Journals (Sweden)

    Guo Li

    Full Text Available Mechanistic investigations have shown that, upon agonist activation, hydroxy-carboxylic acid receptor-1(HCA1 couples to a Gi protein and inhibits adenylate cyclase activity, leading to inhibition of liberation of free fatty acid. However, the underlying molecular mechanisms for HCA1 signaling remain largely unknown. Using CHO-K1 cells stably expressing HCA1, and L6 cells, which endogenously express rat HCA1 receptors, we found that activation of ERK1/2 by HCA1 was rapid, peaking at 5 min, and was significantly blocked by pertussis toxin. Furthermore, time course experiments with different kinase inhibitors demonstrated that HCA1 induced ERK1/2 activation via the extracellular Ca2+, PKC and IGF-I receptor transactivation-dependent pathways. In addition, we observed that pretreated the cells with M119K, an inhibitor of Gβγ subunit-dependent signaling, effectively attenuated the ERK1/2 activation triggered by HCA1, suggesting a critical role for βγ-subunits in HCA1-activated ERK1/2 phosphorylation. Furthermore, the present results also indicated that the arrestin2/3 were not required for ERK1/2 activation. In conclusion, our findings demonstrate that upon binding to agonist, HCA1 receptors initially activate Gi, leading to dissociation of the Gβγ subunit from activated Gi, and subsequently induce ERK1/2 activation via two distinct pathways: one PKC-dependent pathway and the other IGF-IR transactivation-dependent pathway. Our results provide the first in-depth evidence that defines the molecular mechanism of HCA1-mediated ERK1/2 activation.

  19. Ion exchange studies of alpha-hydroxy carboxylic acid-lanthanide and actinide systems

    International Nuclear Information System (INIS)

    Alpha-hydroxy carboxylic acids have been used extensively for the separation of lanthanide and actinide elements with cation exchange resins. Sorption of these elements in the same solutions occurs on strong base anion-exchange resins. A study has been made by elution and equilibrium distribution techniques of the behaviour at tracer-level concentrations of these anion-exchange systems. One objective was to measure the separation factors to assess anion exchange as a possible complement to cation exchange separation. Since very little attention has been given to characterizing the complexed species present in these separation systems, a second objective was to attempt such characterization through interpretation of both cation and anion exchange data. Glycolic, lactic and alpha-hydroxy isobutyric acids were used together with radioactive tracers of Ce, Pm, Eu, Tb, Tm, Y, Cm and Cf. The elutions and equilibrium distributions were performed both at 25o C and 87o C. In all three eluants, the separation factors were smaller for the anion exchange than for the analogous cation exchange. In the glycolate solutions, the separation factors were largest and the values of the distribution coefficient Kd. indicated that these were the most stable complexes. The plots of log Kd against log anion concentration pass through a maximum and then approach a slope of -1, indicating the presence of an anionic complex MX4-. The existence of this negative complex in the solution phase was demonstrated by electromigration studies of Tm170 tracer in these solutions. At the solution concentration corresponding to the maximum Kd value, it can be shown that the predominant solution species is MX3. Approximate successive stability constants have been calculated for these systems and with these it is possible to construct diagrams showing the relative concentration of the species M+3, MX+2, MX2+, MX3 and MX4- as a function of the concentration of X-. (author)

  20. Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes.

    Science.gov (United States)

    Dong, Ki-Young; Choi, Jinnil; Lee, Yang Doo; Kang, Byung Hyun; Yu, Youn-Yeol; Choi, Hyang Hee; Ju, Byeong-Kwon

    2013-01-01

    Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas.

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

    International Nuclear Information System (INIS)

    2-Thiosemicarbazonobutanoic acid hemihydrate, C5H9N3O2S.0.5H2O, Mr=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) A3, Z=4, Dx=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.)

  2. An easy and direct method for the synthesis of 1,2,4-triazole derivatives through carboxylic acids and hydrazinophthalazine

    OpenAIRE

    Gildardo Rivera; Virgilio Bocanegra-Garcia; Antonio Moreno; Silvia Galiano; Silvia Pérez; Ignacio Aldana; Antonio Monge

    2008-01-01

    We have developed an easy method for the synthesis of thirteen compounds derived from 1,2,4-triazoles through a carboxylic acid and hydrazinophthalazine reaction, with a 75-85% yield mediated by the use of agents such as 1-ethyl-3-(3'-dimethylaminopropyl)-carbodiimide hydrochloride and 1-hydroxybenzotriazole. The operational simplicity of this method and the good yield of products make it valuable for the synthesis of new compounds with pharmacological activity.

  3. An efficient way to coupling amine with derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid

    Institute of Scientific and Technical Information of China (English)

    Feng Zhi Liu; Hao Fang; Wen Fang Xu

    2007-01-01

    An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper.We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method. As a substitute, the mixed anhydride method was adopted. A series of 6-(3-nitroguanidino)hexanamidopyrrolidine derivatives were prepared with this method.

  4. An easy and direct method for the synthesis of 1,2,4-triazole derivatives through carboxylic acids and hydrazinophthalazine

    Directory of Open Access Journals (Sweden)

    Gildardo Rivera

    2008-01-01

    Full Text Available We have developed an easy method for the synthesis of thirteen compounds derived from 1,2,4-triazoles through a carboxylic acid and hydrazinophthalazine reaction, with a 75-85% yield mediated by the use of agents such as 1-ethyl-3-(3'-dimethylaminopropyl-carbodiimide hydrochloride and 1-hydroxybenzotriazole. The operational simplicity of this method and the good yield of products make it valuable for the synthesis of new compounds with pharmacological activity.

  5. Synthesis, Chiroptical Behavior, and Sensing of Carboxylic Acid Functionalized.Poly(phenylene ethynylene-alt-bithiophene)s

    OpenAIRE

    Vandeleene, Steven; Verswyvel, Michiel; Verbiest, Thierry; Koeckelberghs, Guy

    2010-01-01

    Several poly(phenylene ethynylene-alt-bithiophene)s with (chiral) nonfunctionalized substituents were synthesized with a variable phenylene ethynylene (PE) spacer length (up to 4 repeating units). The chiroptical behavior was evaluated with UV vis and circular dichroism (CD) spectroscopy, revealing a highly solvent-sensitive aggregate formation. Based on this high sensitivity, both chiral and achiral carboxylic acid functionalized analogues were prepared, of which the length of the spacer con...

  6. A Simple Method for the Determination of Enantiomeric Excess and Identity of Chiral Carboxylic Acids

    OpenAIRE

    Joyce, Leo A.; Maynor, Marc S.; Dragna, Justin M.; da Cruz, Gabriella M.; Lynch, Vincent M.; Canary, James W.; Eric V. Anslyn

    2011-01-01

    The association between an achiral copper(II) host (1) and chiral carboxylate guests was studied using exciton-coupled circular dichroism (ECCD). Enantiomeric complexes were created upon binding of the enantiomers of the carboxylate guests to the host, and the sign of the resultant CD signal allowed for determination of the configuration of the studied guest. The difference in magnitudes and shapes of the CD signals, in conjunction with linear discriminant analysis (LDA), allowed for the iden...

  7. 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)

    Brazil santos green coffee beans were irradiated with 60Co-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)

  8. Formation of 4'-carboxyl acid metabolite of imrecoxib by rat liver microsomes

    Institute of Scientific and Technical Information of China (English)

    Hai-yan XU; Peng ZHANG; Ai-shen GONG; Yu-ming SUN; Feng-ming CHU; Zong-ru GUO; Da-fang ZHONG

    2006-01-01

    Aim:Imrecoxib is a novel and moderately selective COX-2 inhibitor.The aim of the present in vitro investigation was to study the formation of the major metabolite 4'-carboxylic acid imrecoxib (M2) and identify the enzyrne(s) involved in the reaction.Methods:The formation of M2 was studied in rat liver cytosol in the absence or presence of liver microsomes.The formed metabolite was identified and quantified by LC/MSn.In addition,to characterize the cytochrome P450 (CYP) isozymes involved in M2 formation,the effects of typical CYP inhibitors (such as ketoconazle,quinine,α-naphthoflavone, methylpyrazole,and cimetidine) on the formation rate of M2 were investigated.Results:The formation of M2 from 4'hydroxymethyl imrecoxib (M4) was completely dependent on rat liver microsomes and NADPH.Enzyme kinetic studies demonstrated that the formation rate of M2 conformed to monophasic Michaelis-Menten kinetics.Additional experiments showed that the formation of M2 was induced significantly by dexamethasone and lowered by ketoconazole strongly and concentration-dependently.By comparison.other CYP inhibitors.such as α-naphthoflavone,cimetidine,quinine,and methylpyrazole had no inhibitory effects on this metabolic pathway.Conclusion:These biotransformation studies of M4 and imrecoxib in rat liver at the subcellular level showed that the formation of M2 occurs in rat liver microsomes and is NADPH-dependent.The reaction was mainly catalyzed by CYP 3A in untreated rats and in dexamethasone-induced rats.Other CYP,such as CYP 1A,2C,2D,and 2E,seem unlikely to participate in this metabolic pathway.

  9. Spectral and biological evaluation of a synthetic antimicrobial peptide derived from 1-aminocyclohexane carboxylic acid.

    Science.gov (United States)

    Abercrombie, J J; Leung, Kai P; Chai, Hanbo; Hicks, Rickey P

    2015-03-15

    Ac-GF(A6c)G(A6c)K(A6c)G(A6c)F(A6c)G(A6c)GK(A6c)KKKK-amide (A6c=1-aminocyclohexane carboxylic acid) is a synthetic antimicrobial peptide (AMP) that exhibits in vitro inhibitory activity against drug resistant strains of Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterococcus faecium at concentrations ranging from 10.9 to 43μM. Spectroscopic investigations were conducted to determine how this AMP interacts with simple membrane model systems in order to provide insight into possible mechanisms of action. CD and 2D-(1)H NMR experiments indicated this AMP on binding to SDS and DPC micelles adopts conformations with varying percentages of helical and random coil conformers. CD investigations in the presence of three phospholipid SUVs consisting of POPC, 4:1 POPC/POPG, and 60% POPE/21%POPG/19%POPC revealed: (1) The interactions occurring with POPC SUVs have minimal effect on the conformational diversity of the AMP yielding conformations similar to those observed in buffer. (2) The interactions with 4:1 POPC/POPG, and 60% POPE/21%POPG/19%POPC SUVs exhibited a greater influence on the percentage of different conformers contributing to the CD spectra. (3) The presence of a high of percentage of helical conformers was not observed in the presence of SUVs as was the case with micelles. This data indicates that the diversity of surface bound conformations adopted by this AMP are very different from the diversity of conformations adopted by this AMP on insertion into the lipid bilayer. CD spectra of this AMP in the presence of SUVs consisting of LPS isolated from P. aeruginosa, K. pneumoniae and Escherichia coli exhibited characteristics associated with various helical conformations.

  10. Papain adulteration in 11-nor-Delta9-tetrahydrocannabinol- 9-carboxylic acid-positive urine samples.

    Science.gov (United States)

    Larson, Scott J; Holler, Justin M; Magluilo, Joseph; Dunkley, Christopher S; Jacobs, Aaron

    2008-01-01

    The adulteration of urine samples is an ongoing problem in forensic drug-testing laboratories, even in the military where the practice of observed collections is performed. These adulterants are used to produce a false-negative result when samples are analyzed for drugs of abuse. It has been reported that papain, a cysteine protease, could be successfully used as a urine adulterant, altering the concentration of 11-nor-Delta9-tetrahydrocannabinol-9- carboxylic acid (THCCOOH) in urine samples. The current study analyzes the effects of latex papain (Sigma, 10 mg/mL) and Lawry's Adolph's Meat Tenderizer (papain is an active ingredient, 10 mg/mL) on immunoassays (FPIA, EMIT, KIMS) and gas chromatography-mass spectrometry (GC-MS) analysis for biological samples. The samples were analyzed initially between 2 and 4 h and then at 1-, 3-, 7-, and 10-day time intervals after the addition of papain. A decrease in response averaged over the course of the study was observed with FPIA (Abbott, 22%) and EMIT (Syva) Dade Behring, 26%, Microgenics, 10%) screening assays by the addition of latex papain to the samples. An increase in response was found using the KIMS (Roche) assay (156% increase). In addition, the GC-MS results (27% decrease) demonstrate that papain affects both the screening and confirmation assays. The addition of meat tenderizer caused decrease in the FPIA (Abbott, 11%) screening assay and GC-MS results (22%) similar to the latex papain while having varied results on the other screening assays. This study confirms papain could be a potential problem for urine drug-testing programs. PMID:18652751

  11. Tracer studies of carboxylic acids. VII. Oxygen-18 exchange of propionic acid with solvent water and with surfactant solubilized water in benzene

    Energy Technology Data Exchange (ETDEWEB)

    Lomax, T.D.; O' Connor, C.J.

    1978-08-30

    Oxygen atom exchange between propionic acid/propionate ion and solubilized H/sub 2//sup 18/O has been measured in micellar solutions of dodecylammonium propionate in benzene and in aqueous solutions of ammonium propionate. The size of the solubilized waterpool affects the rate of exchange of carboxylate oxygen atoms in the presence of mineral acid but not in its absence. 3 figures, 1 table.

  12. Reactivity of sarcosine and 1,3-thiazolidine-4-carboxylic acid towards salicylaldehyde-derived alkynes and allenes

    OpenAIRE

    Laia, Fernanda M. Ribeiro; Gomes, Clara S. B.; Melo, Teresa M.V.D. Pinho e

    2013-01-01

    The reaction of sarcosine and 1,3-thiazolidine-4-carboxylic acid with salicylaldehyde-derived alkynes and allenes opened the way to new chromeno[4,3-b]pyrrole and chromeno[2,3-b]pyrrole derivatives. Tetrahydro-chromeno[4,3-b]pyrroles were obtained from the reaction of these secondary amino acids with O-propargylsalicylaldehyde. Interestingly, sarcosine reacted with ethyl 4-(2-formylphenoxy)but-2-ynoate to give a monocyclic pyrrole resulting from rearrangement of the initially formed 1,3-dipol...

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

    OpenAIRE

    Juranic, Ivan O.; BRATISLAV Z. JOVANOVIC; UBAVKA B. MIOC; LJUBINKA J. BOGUNOVIC

    2000-01-01

    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 calcul...

  14. Selectivity of substrate binding and ionization of 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase.

    Science.gov (United States)

    Luanloet, Thikumporn; Sucharitakul, Jeerus; Chaiyen, Pimchai

    2015-08-01

    2-Methyl-3-hydroxypyridine-5-carboxylic acid (MHPC) oxygenase (EC 1.14.12.4) from Pseudomonas sp. MA-1 is a flavin-dependent monooxygenase that catalyzes a hydroxylation and aromatic ring cleavage reaction. The functional roles of two residues, Tyr223 and Tyr82, located ~ 5 Å away from MHPC, were characterized using site-directed mutagenesis, along with ligand binding, product analysis and transient kinetic experiments. Mutation of Tyr223 resulted in enzyme variants that were impaired in their hydroxylation activity and had Kd values for substrate binding 5-10-fold greater than the wild-type enzyme. Because this residue is adjacent to the water molecule that is located next to the 3-hydroxy group of MHPC, the results indicate that the interaction between Tyr223, H2 O and the 3-hydroxyl group of MHPC are important for substrate binding and hydroxylation. By contrast, the Kd for substrate binding of Tyr82His and Tyr82Phe variants were similar to that of the wild-type enzyme. However, only ~ 40-50% of the substrate was hydroxylated in the reactions of both variants, whereas most of the substrate was hydroxylated in the wild-type enzyme reaction. In free solution, MHPC or 5-hydroxynicotinic acid exists in a mixture of monoanionic and tripolar ionic forms, whereas only the tripolar ionic form binds to the wild-type enzyme. The binding of tripolar ionic MHPC would allow efficient hydroxylation through an electrophilic aromatic substitution mechanism. For the Tyr82His and Tyr82Phe variants, both forms of substrates can bind to the enzymes, indicating that the mutation at Tyr82 abolished the selectivity of the enzyme towards the tripolar ionic form. Transient kinetic studies indicated that the hydroxylation rate constants of both Tyr82 variants are approximately two- to 2.5-fold higher than that of the wild-type enzyme. Altogether, our findings suggest that Tyr82 is important for the binding selectivity of MHPC oxygenase towards the tripolar ionic species, whereas the

  15. 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...... reaction is most likely involved in this case. The kinetic isotope effect was determined to be 0.67 using 1-butanol as the substrate. A plausible catalytic cycle was characterized by DFT/B3LYP-D3 and involved coordination of the alcohol to the metal, β-hydride elimination, hydroxide attack...... on the coordinated aldehyde, and a second β-hydride elimination to furnish the carboxylate....

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

    OpenAIRE

    Jennifer, Samson Jegan; Muthiah, Packianathan Thomas

    2014-01-01

    Background 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 forme...

  17. Biosynthesis of 1-aminocyclopropane-1-carboxylic acid and ethylene from delta-aminolevulinic acid in ripening tomato fruits

    Energy Technology Data Exchange (ETDEWEB)

    El-Rayes, D.E.D.A.

    1987-01-01

    A new pathway for ethylene (C/sub 2/H/sub 4/) biosynthesis, which utilizes delta-aminolevulinic acid (ALA) as a precursor of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of C/sub 2/H/sub 4/, is presented. ALA enhanced ACC accumulation to 410% and C/sub 2/H/sub 4/ production to 232% of the control. The C/sub 2/H/sub 4/ production rate varied with the ALA concentration and the stage of tomato fruit development. As the ALA concentration increased from zero to 40 mM, the C/sub 2/H/sub 4/ production rate increased. Both treated and untreated pericarp discs from fruits at the pink stage of development yielded the largest C/sub 2/H/sub 4/ production rate. Radioactivity from (2,3-/sup 3/H)ALA was detected in both ACC and C/sub 2/H/sub 4/, and radioactivity from (4-/sup 14/C)ALA was detected in ACC and CO/sub 2/ but not in C/sub 2/H/sub 4/. However, radioactivity from (5-/sup 14/C)ALA was detected in CO/sub 2/, and its amount was greater than that obtained from (4-/sup 14/C)ALA. Neither ACC nor C/sub 2/H/sub 4/ showed any radioactivity when (5-/sup 14/C)ALA was supplied to the fruit discs. In addition, when (2,3-/sup 3/H)ALA or (4-/sup 14/C)ALA was supplied to the fruit discs, radioactivity was detected in other metabolites such as fumarate, succinate, malate, glutamate, glutamine, ..cap alpha..-ketoglutarate, and methionine, but the amount of radioactivity was insignificant as compared with the amount of radioactivity found in C/sub 2/H/sub 4/ and ACC.

  18. Chiral Integrated Catalysts Composed of Bifunctional Thiourea and Arylboronic Acid: Asymmetric Aza-Michael Addition of α,β-Unsaturated Carboxylic Acids.

    Science.gov (United States)

    Hayama, Noboru; Azuma, Takumi; Kobayashi, Yusuke; Takemoto, Yoshiji

    2016-01-01

    The first intermolecular asymmetric Michael addition of nitrogen-nucleophiles to α,β-unsaturated carboxylic acids was achieved through a new type of arylboronic acid equipped with chiral aminothiourea. The use of BnONH2 as a nucleophile gives a range of enantioenriched β-(benzyloxy)amino acid derivatives in good yields and with high enantioselectivity (up to 90% yield, 97% enantiomeric excess (ee)). The obtained products are efficiently converted to optically active β-amino acid and 1,2-diamine derivatives. PMID:27373626

  19. A Novel and Facile Synthesis of 2-(Benzofuran-2-yl)benzo[h]- quinoline-3-carboxylic Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    高文涛; 姜云; 李阳; 李凤; 闫岩

    2012-01-01

    A simple and concise approach for the synthesis of a series of new heterocyclic systems of 2-(benzofuran-2-yl)- benzo[h]quinoline-3-carboxylic acid derivatives (3a--3g) is described. The synthetic strategy features the one-pot reaction of ethyl 2-(chloromethyl)benzo[h]quinoline-3-carboxylate (2) with various substituted salicylaldehydes as well as 2-hydroxy-l-naphthaldehyde as a key step. The substrate 2 was prepared in good yield by a mild, efficient and direct reaction of 1-naphthylamine (1) with Vilsmeier-Haack reagent. The structures of all the new compounds were identified by spectral data and elemental analysis.

  20. Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination.

    Science.gov (United States)

    Bosire, G O; Ngila, J C; Parshotam, H

    2016-01-01

    The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™ X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges. PMID:27274730

  1. 2-sec-Butyl-1-(2-hydroxyethyl-1H-benzimidazole-5-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Nurasyikin Hamzah

    2012-07-01

    Full Text Available In the title compound, C14H18N2O3, the carboxylic group is tilted by 12.00 (4° with respect to the mean plane throught the benzimidazole ring system. The alcohol and carboxyl hydroxy groups are involved in intermolecular O—H...O and O—H...N hydrogen bonds, forming a two-dimensional network extending parallel the ab plane. The network is further stabilized by weak C—H...O interactions. The sec-butyl group is disordered over two sets of sites with refined occupancies of 0.484 (4 and 0.516 (4.

  2. 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 Ba2+ 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.

  3. Effect of hydrogen and carbon dioxide on carboxylic acids patterns in mixed culture fermentation

    NARCIS (Netherlands)

    Arslan, D.; Steinbusch, K.J.J.; Diels, L.; Wever, De H.; Buisman, C.J.N.; Hamelers, H.V.M.

    2012-01-01

    This study investigated the carboxylate spectrum from mixed culture fermentation of three organic waste streams after supplying 2 bar hydrogen and carbon dioxide or a mixture of these two gases to the headspace. Under any modified headspace, propionate production was ceased and butyrate, caproate an

  4. Effect of Molecular Structure on the Relative Hydrogen Peroxide Scavenging Ability of Some α-Keto Carboxylic Acids.

    Science.gov (United States)

    Lopalco, Antonio; Stella, Valentino J

    2016-09-01

    The α-keto carboxylic acid, pyruvic acid (1) was found to be a very effective peroxide scavenger but is subject to an aldol-like self-condensation/polymerization reaction. The purpose of this study was to evaluate the hydrogen peroxide, H2O2, scavenging ability of 3-methyl-2-oxobutanoic acid (2), 4-methyl-2-oxopentanoic acid (3), and 2-oxo-2-phenylacetic acid (phenylglyoxylic acid, 4) in the pH range 2-9 at 25°C and the effect of molecular structure on the relative reactivity. The reaction with H2O2 was followed by UV spectrophotometry at 220 or 260 nm and high-performance liquid chromatography. Pseudo-first order, buffer-independent decarboxylation kinetics were observed in the presence of molar excess H2O2. The second-order rate constants for 2-4 followed a sigmoidal shape and mechanism similar to pyruvic acid. Pyruvic acid was a superior H2O2 scavenger to 2-4 over the pH range 2-9 but 4 was more reactive than 2 and 3 at pH values above 6. There was a qualitative correlation between the degree of keto-group hydration and reactivity of the acids in the pH range 4-6 while the data above pH 7 suggested that the intrinsic decarboxylation step for 4 was faster than for pyruvic acid. Differences in reactivity to molecular structure were analyzed. PMID:27209460

  5. Trace amounts of furan-2-carboxylic acids determine the quality of solid agar plates for bacterial culture.

    Directory of Open Access Journals (Sweden)

    Shintaro Hara

    Full Text Available BACKGROUND: Many investigators have recognised that a significant proportion of environmental bacteria exist in a viable but non-culturable state on agar plates, and some researchers have also noticed that some of such bacteria clearly recover their growth on matrices other than agar. However, the reason why agar is unsuitable for the growth of some bacteria has not been addressed. METHODOLOGY/PRINCIPAL FINDINGS: According to the guide of a bioassay for swarming inhibition, we identified 5-hydroxymethylfuran-2-carboxylic acid (5-HMFA and furan-2-carboxylic acid (FA as factors that inhibit bacterial swarming and likely inhibit extracellular polysaccharide production on agar. The furan-2-carboxylic acids 5-HMFA and FA effectively inhibited the swarming and swimming of several environmental bacteria at concentrations of 1.8 and 2.3 µg L(-1 (13 and 21 nmol L(-1, respectively, which are equivalent to the concentrations of these compounds in 0.3% agar. On Luria-Bertani (LB plates containing 1.0% agar that had been previously washed with MeOH, a mixture of 5-HMFA and FA in amounts equivalent to their original concentrations in the unwashed agar repressed the swarming of Escherichia coli K12 strain W3110, a representative swarming bacterium. CONCLUSIONS/SIGNIFICANCE: Agar that contains trace amounts of 5-HMFA and FA inhibits the proliferation of some slow-growing or difficult-to-culture bacteria on the plates, but it is useful for single colony isolation due to the ease of identification of swarmable bacteria as the non-swarmed colonies.

  6. Toxicity of Carboxylic Acid-Containing Drugs: The Role of Acyl Migration and CoA Conjugation Investigated.

    Science.gov (United States)

    Lassila, Toni; Hokkanen, Juho; Aatsinki, Sanna-Mari; Mattila, Sampo; Turpeinen, Miia; Tolonen, Ari

    2015-12-21

    Many carboxylic acid-containing drugs are associated with idiosyncratic drug toxicity (IDT), which may be caused by reactive acyl glucuronide metabolites. The rate of acyl migration has been earlier suggested as a predictor of acyl glucuronide reactivity. Additionally, acyl Coenzyme A (CoA) conjugates are known to be reactive. Here, 13 drugs with a carboxylic acid moiety were incubated with human liver microsomes to produce acyl glucuronide conjugates for the determination of acyl glucuronide half-lives by acyl migration and with HepaRG cells to monitor the formation of acyl CoA conjugates, their further conjugate metabolites, and trans-acylation products with glutathione. Additionally, in vitro cytotoxicity and mitochondrial toxicity experiments were performed with HepaRG cells to compare the predictability of toxicity. Clearly, longer acyl glucuronide half-lives were observed for safe drugs compared to drugs that can cause IDT. Correlation between half-lives and toxicity classification increased when "relative half-lives," taking into account the formation of isomeric AG-forms due to acyl migration and eliminating the effect of hydrolysis, were used instead of plain disappearance of the initial 1-O-β-AG-form. Correlation was improved further when a daily dose of the drug was taken into account. CoA and related conjugates were detected primarily for the drugs that have the capability to cause IDT, although some exceptions to this were observed. Cytotoxicity and mitochondrial toxicity did not correlate to drug safety. On the basis of the results, the short relative half-life of the acyl glucuronide (high acyl migration rate), high daily dose and detection of acyl CoA conjugates, or further metabolites derived from acyl CoA together seem to indicate that carboxylic acid-containing drugs have a higher probability to cause drug-induced liver injury (DILI). PMID:26558897

  7. Analysis of liposoluble carboxylic acids metabolome in human serum by stable isotope labeling coupled with liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Zhu, Quan-Fei; Zhang, Zheng; Liu, Ping; Zheng, Shu-Jian; Peng, Ke; Deng, Qian-Yun; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-08-19

    Fatty acids (FAs) are groups of liposoluble carboxylic acids (LCAs) and play important roles in various physiological processes. Abnormal contents or changes of FAs are associated with a series of diseases. Here we developed a strategy with stable isotope labeling combined with liquid chromatography-tandem mass spectrometry (IL-LC-MS) analysis for comprehensive profiling and relative quantitation of LCAs in human serum. In this strategy, a pair of isotope labeling reagents (2-dimethylaminoethylamine (DMED)) and d4-2-dimethylaminoethylamine (d4-DMED) were employed to selectively label carboxyl groups of LCAs. The DMED and d4-DMED labeled products can lose four characteristic neutral fragments of 45 and 49Da or 63 and 67Da in collision-induced dissociation. Therefore, quadruple neutral loss scan (QNLS) mode was established and used for non-targeted profiling of LCAs. The peak pairs of DMED and d4-DMED labeling with the same retention time, intensity and characteristic mass differences were extracted from the two NLS spectra respectively, and assigned as potential LCA candidates. Using this strategy, 241 LCA candidates were discovered in the human serum; 156 carboxylic acid compounds could be determined by searching HMDB and METLIN databases (FAs are over 90%) and 21 of these LCAs were successfully identified by standards. Subsequently, a modified pseudo-targeted method with multiple reaction monitoring (MRM) detection mode was developed and used for relative quantification of LCAs in human serum from type 2 diabetes mellitus (T2DM) patients and healthy controls. As a result, 81 LCAs were found to have significant difference between T2DM patients and healthy controls. Taken together, the isotope labeling combined with tandem mass spectrometry analysis demonstrated to be a powerful strategy for identification and quantification of LCA compounds in serum samples. PMID:27432792

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

    Science.gov (United States)

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

    2016-08-01

    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.

  9. Conductance measurement of carboxylic acids binding to palladium nanoclusters by electrochemical jump-to-contact STM break junction

    International Nuclear Information System (INIS)

    We measured the single-molecule conductance of alkanedicarboxylic acid (HOOC − (CH2)n − COOH, n = 1 − 5) with Pd nanoclusters by electrochemical jump-to-contact STM-break junction. They gave out decay constant βN of 0.652 per (−CH2) unit and contact conductance of 97 nS. The single-molecule conductance of carboxylic acid binding to bulk metal electrode was also studied, and has almost the same value as that binding to Pd nanoclusters. The conductance study on Pd-oxalic acid junctions shows that the electron transfer through the ultrashort molecular junctions is not only contributed by the “through-bond” (TB) mechanism but also “through-space” (TS) mechanism. Our work provides a new path to study the single-molecule conductance with Pd contacts

  10. Diastereomeric complex of ( R/ S)-piperidine-3-carboxylic acid with (2 R,3 R)-tartaric acid: Structural, spectroscopic and computational studies

    Science.gov (United States)

    Bartoszak-Adamska, E.; Dega-Szafran, Z.; Jaskólski, M.; Szafran, M.

    2011-07-01

    2:2 Complex of ( R) and ( S)-piperidine-3-carboxylic acids (P3C) with (2 R,3 R) -tartaric acid (TA), 1, has been characterized by single-crystal X-ray analysis, FTIR and NMR spectroscopies, and by DFT calculations. The crystals of 1 are monoclinic, space group P2 1. The crystal structure is formed by two distinct P3CH +·TA - components, A and B, linked by an O-H⋯O hydrogen bond of 2.603(2) Å. The A and B components differ in the absolute configuration of the C(3) atom of P3CH +; ( S) in A and ( R) in B. The piperidinium-3-carboxylic acid and (2 R,3 R)-semi-tartrate anion moieties of the components A and B are linked by O-H⋯O hydrogen bonds of 2.517(1) and 2.535(1) Å, respectively. In A and B the piperidinium rings adopt the chair conformation with the carboxyl group in the equatorial position. The structures of the monomers of P3CH +·TA -, 3A and 3B, as well as of a dimer 2, have been optimized by the B3LYP/6-31G(d,p) approach. The chemical shift assignments were based on two-dimensional 1H- 1H and 1H- 13C experiments.

  11. A sensitive and selective imprinted solid phase extraction coupled to HPLC for simultaneous detection of trace quinoxaline-2-carboxylic acid and methyl-3-quinoxaline-2-carboxylic acid in animal muscles.

    Science.gov (United States)

    Duan, Zhenjuan; Yi, Jianghua; Fang, Guozhen; Fan, Lipeng; Wang, Shuo

    2013-08-15

    A new molecularly imprinted polymer (MIP), selective for major metabolites of quinoxaline-1,4-dioxides, was prepared through bulk polymerisation using quinoxaline-2-carboxylic acid (QCA) as template, diethylaminoethylmethacrylate as functional monomer and ethylene glycol dimethacrylate as cross-linker in tetrahydrofuran. The synthesised MIP was characterised by Fourier transform infrared and adsorption experiments. MIP exhibited high affinity, fast kinetics for QCA and good selectivity for QCA and methyl-3-quinoxaline-2-carboxylic acid (MQCA). MIP obtained was used as a selective sorbent for molecularly imprinted solid phase extraction (MISPE) coupled with HPLC to detect QCA and MQCA. Under the optimal conditions, the limits of detection (S/N=3) of porcine, chicken and fish muscles were 0.1, 0.3, 0.1 μg/kg for QCA and 0.2, 0.3, 0.1 μg/kg for MQCA, respectively and good recoveries were obtained in the range from 60.0 to 119.4%. These results indicated the MISPE-HPLC procedure could be successfully used for the determination QCA and MQCA in animal muscles.

  12. Effects of carboxylic acids on the uptake of non-transferrin-bound iron by astrocytes.

    Science.gov (United States)

    Keenan, Belinda M; Robinson, Stephen R; Bishop, Glenda M

    2010-01-01

    The concentrations of non-transferrin-bound iron are elevated in the brain during pathological conditions such as stroke and Alzheimer's disease. Astrocytes are specialised for sequestering this iron, however little is known about the mechanisms involved. Carboxylates, such as citrate, have been reported to facilitate iron uptake by intestinal cells. Citrate binds iron and limits its redox activity. The presence of high citrate concentrations in the interstitial fluid of the brain suggests that citrate may be an important ligand for iron transport by astrocytes. This study investigates whether iron accumulation by cultured rat astrocytes is facilitated by citrate or other carboxylates. Contrary to expectations, citrate, tartrate and malate were found to block iron accumulation in a concentration-dependent manner; alpha-ketoglutarate had limited effects, while fumarate, succinate and glutarate had no effect. This blockade was not due to an inhibition of ferric reductase activity. Instead, it appeared to be related to the capacity of these carboxylates to bind iron, since phosphate, which also binds iron, diminished the capacity of citrate, tartrate and malate to block the cellular accumulation of iron. These findings raise the possibility that citrate may have therapeutic potential in the management of neurodegenerative conditions that involve cellular iron overload.

  13. Conformational equilibria and large-amplitude motions in dimers of carboxylic acids: rotational spectrum of acetic acid-difluoroacetic acid.

    Science.gov (United States)

    Gou, Qian; Feng, Gang; Evangelisti, Luca; Caminati, Walther

    2014-10-01

    We report the rotational spectra of two conformers of the acetic acid-difluoroacetic acid adduct (CH3COOH-CHF2COOH) and supply information on its internal dynamics. The two conformers differ from each other, depending on the trans or gauche orientation of the terminal -CHF2 group. Both conformers display splittings of the rotational transitions, due to the internal rotation of the methyl group of acetic acid. The corresponding barriers are determined to be V3(trans)=99.8(3) and V3(gauche)=90.5(9) cm(-1) (where V3 is the methyl rotation barrier height). The gauche form displays a further doubling of the rotational transitions, due to the tunneling motion of the -CHF2 group between its two equivalent conformations. The corresponding B2 barrier is estimated to be 108(2) cm(-1). The increase in the distance between the two monomers upon OH→OD deuteration (the Ubbelohde effect) is determined.

  14. One-Pot Synthesis of α-Amino Acids through Carboxylation of Ammonium Ylides with CO2 Followed by Alkyl Migration.

    Science.gov (United States)

    Mita, Tsuyoshi; Sugawara, Masumi; Sato, Yoshihiro

    2016-06-17

    A simple, yet powerful protocol for α-amino acid synthesis using carbon dioxide (CO2) was developed. α-Amino silanes could undergo four successive reactions (formation of ammonium salt, carboxylation, esterification, and 2,3- or 1,2-Stevens rearrangement) in the presence of allylic or benzylic halides under a CO2 atmosphere (1 atm). It is noteworthy that carboxylation at the position adjacent to a nitrogen atom proceeded via an ammonium ylide intermediate under mild conditions.

  15. [Determination of the residues of 3-methyl-quinoxaline-2-carboxylic acid and quinoxaline-2-carboxylic acid in animal origin foods by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zheng, Ling; Wu, Yujie; Li, Yong; Li, Lihua

    2012-07-01

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was developed for the simultaneous quantitative determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) and quinoxaline-2-carboxylic acid (QCA) as the marker residues for carbadox (CBX) and olaquindox (OLA), respectively, in the muscles and livers of porcine and chicken and in the muscles of fish and shrimp. The MQCA and QCA were deproteinated with 5% metaphosphoric acid in 10% methanol followed by liquid-liquid extraction. Further clean-up was performed by solid phase extraction (SPE) through mixed mode anion-exchange columns (Oasis MAX SPE). The separation of the compounds was carried on a Waters Xterra MS C18 column (150 mm x 2.1 mm, 5 microm) by a gradient elution using methanol and 0.2% formic acid as mobile phases. The analytes were detected by tandem mass spectrometry in multiple reaction monitoring (MRM) mode with positive electrospray ionization. The MQCA and QCA were quantified by internal standard method. The linear ranges were 1.0-20.0 microg/L and the correlation coefficients were not less than 0.9996. The average recoveries and relative standard deviations ranged from 62.4%-118% and 1.48%-28.1% respectively at the spiked levels of 0.1, 0.2 and 1.0 microg/kg for the both markers. The limit of quantitation (LOQ) was 0.1 microg/kg. The method is sensitive, accurate and suitable for the determination and confirmation of MQCA and QCA in animal origin foods.

  16. Additional Nucleophile-Free FeCl3-Catalyzed Green Deprotection of 2,4-Dimethoxyphenylmethyl-Protected Alcohols and Carboxylic Acids.

    Science.gov (United States)

    Sawama, Yoshinari; Masuda, Masahiro; Honda, Akie; Yokoyama, Hiroki; Park, Kwihwan; Yasukawa, Naoki; Monguchi, Yasunari; Sajiki, Hironao

    2016-01-01

    The deprotection of the methoxyphenylmethyl (MPM) ether and ester derivatives can be generally achieved by the combinatorial use of a catalytic Lewis acid and stoichiometric nucleophile. The deprotections of 2,4-dimethoxyphenylmethyl (DMPM)-protected alcohols and carboxylic acids were found to be effectively catalyzed by iron(III) chloride without any additional nucleophile to form the deprotected mother alcohols and carboxylic acids in excellent yields. Since the present deprotection proceeds via the self-assembling mechanism of the 2,4-DMPM protective group itself to give the hardly-soluble resorcinarene derivative as a precipitate, the rigorous purification process by silica-gel column chromatography was unnecessary and the sufficiently-pure alcohols and carboxylic acids were easily obtained in satisfactory yields after simple filtration. PMID:27373632

  17. 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. PMID:21391670

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

    International Nuclear Information System (INIS)

    The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH3(CH2)10COOH and hexadecanoic acid, CH3(CH2)14COOH 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)

  19. Total Acid Value Titration of Hydrotreated Biomass Fast Pyrolysis Oil: Determination of Carboxylic Acids and Phenolics with Multiple End-Point Detection

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, E.; Alleman, T. L.; McCormick, R. L.

    2013-01-01

    Total acid value titration has long been used to estimate corrosive potential of petroleum crude oil and fuel oil products. The method commonly used for this measurement, ASTM D664, utilizes KOH in isopropanol as the titrant with potentiometric end point determination by pH sensing electrode and Ag/AgCl reference electrode with LiCl electrolyte. A natural application of the D664 method is titration of pyrolysis-derived bio-oil, which is a candidate for refinery upgrading to produce drop in fuels. Determining the total acid value of pyrolysis derived bio-oil has proven challenging and not necessarily amenable to the methodology employed for petroleum products due to the different nature of acids present. We presented an acid value titration for bio-oil products in our previous publication which also utilizes potentiometry using tetrabutylammonium hydroxide in place of KOH as the titrant and tetraethylammonium bromide in place of LiCl as the reference electrolyte to improve the detection of these types of acids. This method was shown to detect numerous end points in samples of bio-oil that were not detected by D664. These end points were attributed to carboxylic acids and phenolics based on the results of HPLC and GC-MS studies. Additional work has led to refinement of the method and it has been established that both carboxylic acids and phenolics can be determined accurately. Use of pH buffer calibration to determine half-neutralization potentials of acids in conjunction with the analysis of model compounds has allowed us to conclude that this titration method is suitable for the determination of total acid value of pyrolysis oil and can be used to differentiate and quantify weak acid species. The measurement of phenolics in bio-oil is subject to a relatively high limit of detection, which may limit the utility of titrimetric methodology for characterizing the acidic potential of pyrolysis oil and products.

  20. Cysteine amide adduct formation from carboxylic acid drugs via UGT-mediated bioactivation in human liver microsomes.

    Science.gov (United States)

    Harada, H; Toyoda, Y; Endo, T; Kobayashi, M

    2015-10-01

    Although chemical trapping has been widely used to evaluate cytochrome P450-mediated drug bioactivation, thus far, only a few in vitro-trapping studies have been performed on UDP-glucuronosyltransferase (UGT)-mediated drug bioactivation. In this study, we used cysteine (Cys) as trapping agent to gain new insights into the UGT-mediated bioactivation involving acyl glucuronides of carboxylic acid drugs. Diclofenac, ketoprofen and ibuprofen were incubated in human liver microsomes with UDPGA and Cys, followed by analysis using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). The N-acyl-Cys amide adduct of diclofenac was characterized by mass analysis and was detectable even in photodiode array analysis. Our data indicated that the formation of such adducts reflects the reactivity of the corresponding acyl glucuronides. In addition, it was suggested that the adduct formation requires an N-terminal Cys moiety with both a free amine and a free thiol group, from the results using various cysteine derivatives. We propose that the S-acyl-Cys thioester adduct can form via transacylation of an acyl glucuronide and can then form to an N-acyl-Cys amide adduct through intramolecular S- to N-acyl rearrangement. This series of the reactions has important implications as a possible bioactivation mechanism for covalent binding of carboxylic acid drugs to macromolecules. PMID:26601426

  1. Syntheses, structures and tunable luminescence of lanthanide metal-organic frameworks based on azole-containing carboxylic acid ligand

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dian; Rao, Xingtang; Yu, Jiancan; Cui, Yuanjing, E-mail: cuiyj@zju.edu.cn; Yang, Yu; Qian, Guodong, E-mail: gdqian@zju.edu.cn

    2015-10-15

    Design and synthesis of a series of isostructural lanthanide metal-organic frameworks (LnMOFs) serving as phosphors by coordinate the H{sub 2}TIPA (5-(1H-tetrazol-5-yl)isophthalic acid) ligands and lanthanide ions is reported. The color of the luminescence can be tuned by adjusting the relative concentration of the lanthanide ions in the host framework GdTIPA, and near-pure-white light emission can be achieved. - Graphical abstract: Lanthanide metal-organic frameworks (LnMOFs) with tunable luminescence were synthesized using an azole-containing carboxylic acid as ligand. - Highlights: • A series of isostructural LnMOFs serving as phosphor is reported. • We model the GdTIPA: Tb{sup 3+}, Eu{sup 3+} which can tune color and emit white light. • The scheme and mechanism of luminescent LnMOFs are also presented and discussed.

  2. Cationic zinc (II) dimers and one dimensional coordination polymer from ionic carboxylic acid

    Indian Academy of Sciences (India)

    Paladugu Suresh; Ganesan Prabusankar

    2014-09-01

    A rare example of chelating two tetra cationic paddle-wheel zinc dimers were synthesized from the reaction between flexible imidazolium carboxylate (LH2Br2) and corresponding zinc precursors. A zinc coordination polymer was synthesised by treating in situ generation of 2 in the presence of 4,4′-bipyridine. These new molecules, dimers and polymer, were characterized by FT-IR, NMR, UV-vis, fluorescent and single crystal X-ray diffraction techniques. Zinc polymer is the first example of 1D coordination polymer constructed by tetra cationic zinc dimer as a secondary building unit in coordination polymer.

  3. Olfaction in Asian tiger mosquito Aedes albopictus: flight orientation response to certain saturated carboxylic acids in human skin emanations.

    Science.gov (United States)

    Seenivasagan, T; Guha, Lopamudra; Parashar, B D; Agrawal, O P; Sukumaran, D

    2014-05-01

    The flight orientation response of nonblood-fed and hungry Aedes albopictus females was studied in a Y-tube olfactometer at 10(-6) to 10(-2) g odor plumes of saturated carboxylic acids (C1-C20), in which C2-C18 were the main constituents of human skin emanations. Thirteen acids viz C1, C2, C3, C5, C6, C8 C9, C10, C12, C14, C16, C18, and C20 showed attractance at odor plumes ranging from 10(-5) to 10(-3) g doses, while five acids viz C4, C7, C11, C15, and C19 showed repellence at 10(-4) to 10(-2) g to test mosquitoes. Tridecanoic acid (C13) showed attractance only at 10(-4) g dose while higher doses caused repellence. Dose-dependent reversal of orientation behavior from attractance to repellence was observed at 10(-2) g plumes of C5, C9, C10, C13, C17, C19, and C20 acids. The outcome of the study will help in the identification of odoriferous acids as potential attractants, repellents, or attraction inhibitors, which may find their application in the repellent formulations and odor-baited traps for surveillance and control of mosquitoes.

  4. 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.

  5. 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

  6. Carrier-Mediated Uptake of 1-(Malonylamino)cyclopropane-1-Carboxylic Acid in Vacuoles Isolated from Catharanthus roseus Cells 1

    Science.gov (United States)

    Bouzayen, Mondher; Latché, Alain; Pech, Jean-Claude; Marigo, Gérard

    1989-01-01

    The uptake of 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC), the conjugated form of the ethylene precursor, into vacuoles isolated from Catharanthus roseus cells has been studied by silicone layer floatation filtering. The transport across the tonoplast of MACC is stimulated fourfold by 5 millimolar MgATP, has a Km of about 2 millimolar, an optimum pH around 7, and an optimum temperature at 30°C. Several effectors known to inhibit ATPase (N,N′-dicyclohexylcarbodiimide) and to collapse the transtonoplastic H+ electrochemical gradient (carbonylcyanide m-chlorophenylhydrazone, gramicidin, and benzylamine) all reduced MACC uptake. Abolishing the membrane potential with SCN− and valinomycin also greatly inhibited MACC transport. Our data demonstrate that MACC accumulates in the vacuole against a concentration gradient by means of a proton motive force generated by a tonoplastic ATPase. The involvement of a protein carrier is suggested by the strong inhibition of uptake by compounds known to block SH—, OH—, and NH2— groups. MACC uptake is antagonized competitively by malonyl-d-tryptophan, indicating that the carrier also accepts malonyl-d-amino acids. Neither the moities of these compounds taken separately [1-aminocyclopropane-1-carboxylic acid, malonate, d-tryptophan or d-phenylalanine] nor malate act as inhibitors of MACC transport. The absence of inhibition of malate uptake by MACC suggests that MACC and malate are taken up by two different carriers. We propose that the carrier identified here plays an important physiological role in withdrawing from the cytosol MACC and malonyl-d-amino acids generated under stress conditions. PMID:16667182

  7. Functionalization of cubic mesoporous silica SBA-16 with carboxylic acid via one-pot synthesis route for effective removal of cationic dyes.

    Science.gov (United States)

    Tsai, Cheng-Hsun; Chang, Wei-Chieh; Saikia, Diganta; Wu, Cheng-En; Kao, Hsien-Ming

    2016-05-15

    In this work, we demonstrate that a high density of COOH groups loading, up to 60mol% based on silica, is successfully incorporated into SBA-16 via a one-pot synthesis route, which involves co-condensation of carboxyethylsilanetriol sodium salt (CES) and tetraethylorthosilicate (TEOS) templated by Pluronic F127 and P123 in an acidic medium. A variety of characterization techniques are performed to confirm quantitative incorporation of carboxylic groups into ordered cubic mesostructures. These functionalized materials are used to effectively remove two cationic dyes methylene blue (MB) and phenosafranine (PF) with the maximum adsorption capacities of 561 and 519mgg(-1), respectively, at pH 9. The zeta potential results reveal that the electrostatic interactions between cationic dye molecule and negatively charged surface of the adsorbent play a crucial role in their high adsorption capacities. For a binary component system consisting of MB and PF, competitive adsorption of these two dyes is observed with adsorption capacity values slightly lower than those of the corresponding single dye systems. The dye adsorbed material can be easily regenerated by simple acid washing and be reused for five times with MB removal efficiency still up to 98.6%, showing its great potentials in environmental remediation. PMID:26906434

  8. Quantitative structure-property relationship study of the solubility of thiazolidine-4-carboxylic acid derivatives using ab initio and genetic algorithm-partial least squares

    Institute of Scientific and Technical Information of China (English)

    Ali Niazi; Saeed Jameh-Bozorghi; Davood Nori-Shargh

    2007-01-01

    A quantitative structure-activity relationships (QSAR) study is suggested for the prediction of solubility of some thiazolidine-4-carboxylic acid derivatives in aqueous solution. Ab initio theory was used to calculate some quantum chemical descriptors including electrostatic potentials and local charges at each atom, HOMO and LUMO energies, etc. Modeling of the solubility of thiazolidine4-carboxylic acid derivatives as a function of molecular structures was established by means of the partial least squares (PLS). The subset of descriptors, which resulted in the low prediction error, was selected by genetic algorithm. This model was applied for the prediction of the solubility of some thiazolidine-4-carboxylic acid derivatives, which were not in the modeling procedure. The relative errors of prediction lower that -4% was obtained by using GA-PLS method. The resulted model showed high prediction ability with RMSEP of 3.8836 and 2.9500 for PLS and GA-PLS models, respectively.

  9. [11C]Carbon Monoxide in Palladium- / Selenium-Promoted Carbonylation Reactions : Synthesis of 11C-Imides, Hydrazides, Amides, Carboxylic Acids, Carboxylic Esters, Carbothioates, Ketones and Carbamoyl Compounds

    OpenAIRE

    Karimi, Farhad

    2002-01-01

    [11C]Carbon monoxide in low concentrations has been used in palladium- or seleniummediated carbonylation reactions such as the synthesis of 11C-imides, hydrazides, amides, carboxylic acids, esters, carbothioates, ketones and carbamoyl compounds. In these reactions aryl iodides have been used in most cases. However, less reactive aryl triflate, chloride and bromides were activated using tetrabutylammonium iodide. The reactivities of nucleophiles may have influence on the radiochemical yield of...

  10. 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.

  11. Bleomycin Loaded Magnetite Nanoparticles Functionalized by Polyacrylic Acid as a New Antitumoral Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Yue Xu

    2013-01-01

    Full Text Available Objective. To prepare, characterize, and analyze the release behavior of bleomycin-loaded magnetite nanoparticles (BLM-MNPs coated with polyacrylic acid (PAA as a new drug delivery system that can be specifically distributed in the tumor site. Methods. BLM-MNPs coated with PAA were prepared using a solvothermal approach. The particles were characterized using scanning electron microscope (SEM, vibrating sample magnetometer (VSM, and Fourier transform infrared spectroscopy (FTIR. The loading and release behaviors of BLM-MNPs were examined by a mathematical formula and in vitro release profile at pH 7.5. Results. The sphere Fe3O4 nanoparticles with the size of approximately 30 nm exhibit a saturation magnetization of 87 emu/g. The noncoordinated carboxylate groups of PAA confer on the good dispersibility in the aqueous solution and lead to a good loading efficiency of BLM reaching 50% or higher. Approximately 98% of immobilized BLM could be released within 24 h, of which 22.4% was released in the first hour and then the remaining was released slowly and quantitatively in the next 23 hours. Conclusion. BLM-MNPs were prepared and characterized successfully. The particles show high saturation magnetization, high drug loading capacity, and favorable release property, which could contribute to the specific delivery and controllable release of BLM, and the BLM-MNPs could be a potential candidate for the development of treating solid tumors.

  12. New silver(I) coordination polymers constructed from pyrazine derivatives and aromatic carboxylic acids: Syntheses, structures and photoluminescence

    Science.gov (United States)

    Zhang, Ting; Huang, Hua-Qi; Mei, Hong-Xin; Wang, Dan-Feng; Wang, Xiao-Xiang; Huang, Rong-Bin; Zheng, Lan-Sun

    2015-11-01

    Five one-dimensional to three-dimensional coordination polymers have been synthesized by 2-chlorobenzoic acid (HL1), 2-nitrobenzoic acid (HL2), o-toluic acid (HL3), 2,3,5-trimethylpyrazine (tpyz) and 2,3,5,6-tetramethylpyrazine (mpyz) in the presence of NH3·H2O in mixed solvents systems, namely, {Ag4(tpyz)2(L1)4}n (1), {Ag2(tpyz) (L2)2}n (2), {Ag2(tpyz) (L3)2}n (3), {Ag2(mpyz) (L1)2}n (4), {Ag(mpyz) (L2) (H2O)}n (5). All the complexes have been characterized by elemental analyses, IR spectra and X-ray diffraction. Compound 1 shows a 3D framework. The tpyz ligand links 1D chain which was connected by silver atom and L1 anion into 3D framework. Compounds 2 and 4 possess a similar 2D network with (4, 4) topology. Complex 3 also exhibits a two-dimensional structure. There is a 1D silver chain in 3, which is the main difference from 2 and 4. So, 3 shows three-connected (4 8, 3) topology. For 5, only one oxygen of L2 coordinated to Ag(I) ions. The L2 anions were arranged in both sides of the chain, which was connected by silver atoms and mpyz ligands. Then, the uncoordinated carboxylate oxygen with coordinated water 1molecule oxygen through the hydrogen bond made the resultant structure to a 3D framework. Complexes 1-5 spanning from one-dimensional chains to three-dimensional framework suggest that carboxylates and the kinds of pyrazine derivatives play significant roles in the formation of such coordination architectures. The photoluminescence and thermogravimetric analysis (TGA) of the complexes were also investigated.

  13. Synthesis and structural characterization of organotin(IV complexes formed with [O,O] donor atoms of carboxylic acids

    Directory of Open Access Journals (Sweden)

    SAQIB ALI

    2008-02-01

    Full Text Available Organotin(IV carboxylates of the general formula RnSnL4-n (where R = Me, n-Bu or Ph, and L = alpha-phenyl-2,3-(methylenedioxycinnamate anion or 2-(2,3-dimethlylanilinonicotinate anion have been prepared. The mono-, di- and tri-organotin(IV carboxylates were synthesized by the reaction of organotin(IV oxides or hydroxides with a stoichiometric amount of the ligand acids at an elevated temperature in dry toluene. The composition of the synthesized organotin(IV complexes, the bonding behavior of the donor groups and structural assignments were studied by elemental analysis, FT-IR, 1H-, 13C-NMR and mass spectrometry. The spectral data suggest that the ligand acts in a bidentate manner, coordinating through the oxygen atoms. These spectroscopic techniques revealed a distorted tetrahedral geometry in the solution state for the tri-organotins, while a mean coordination number between five to six for the di-organotin(IV dicarboxylates. In the solid phase, the tri-organotins were essentially trigonal bipyramidal polymeric while the di-organotins were octahedral. However, mono-organotin tricarboxylates were predicted to exist in the octahedral state both in solution as well as in the solid phase.

  14. QSTR studies regarding the ECOSAR toxicity of benzene-carboxylic acid' esters to fathead minnow fish (Pimephales promelas).

    Science.gov (United States)

    Tarko, Laszlo; Putz, Mihai V; Ionascu, Cosmin; Putz, Ana-Maria

    2014-01-01

    The present work employs 152 benzene-carboxylic acid' esters having computed the toxicity within the range [2.251, 10.222] for fathead minnow fish (Pimephales promelas). Calibration set includes many pairs having very similar chemical structure, size, shape and hydrophilicity, but very different value of ECOSAR toxicity or vice versa. The QSTR study, which uses all esters as calibration set, emphasized a large percent (16.2%) of outliers. In this QSTR study most of the estimated values of toxicity for outliers are much lower than ECOSAR toxicity. The LogP and some aromaticity descriptors are predictors. The best QSTR for esters having low value (toxicity and the best QSTR for esters having high value (> 5.5) of ECOSAR toxicity are obtained when the number of outliers is very small. These QSTRs are different enough and highlight opposite influences of certain descriptors on toxicity. The results emphasize two possibilities: (a) the esters having low value of ECOSAR toxicity and the esters having high value of ECOSAR toxicity are included in two different classes from the point of view of structure-toxicity relationship and/or (b) many high values of ECOSAR toxicity are wrong. By comparison, a QSTR using experimental values of toxicity against rats for 37 benzene-carboxylic esters included in the same database gives good correlation experimental/computed values of toxicity, the number of outliers is null and the result of validation test is good. PMID:24724900

  15. 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.

  16. Comparative Study on Single-Molecule Junctions of Alkane- and Benzene-Based Molecules with Carboxylic Acid/Aldehyde as the Anchoring Groups

    Science.gov (United States)

    Chen, Fang; Peng, Lin-Lu; Hong, Ze-Wen; Mao, Jin-Chuan; Zheng, Ju-Fang; Shao, Yong; Niu, Zhen-Jiang; Zhou, Xiao-Shun

    2016-08-01

    We have measured the alkane and benzene-based molecules with aldehyde and carboxylic acid as anchoring groups by using the electrochemical jump-to-contact scanning tunneling microscopy break junction (ECSTM-BJ) approach. The results show that molecule with benzene backbone has better peak shape and intensity than those with alkane backbone. Typically, high junction formation probability for same anchoring group (aldehyde and carboxylic acid) with benzene backbone is found, which contributes to the stronger attractive interaction between Cu and molecules with benzene backbone. The present work shows the import role of backbone in junction, which can guide the design molecule to form effective junction for studying molecular electronics.

  17. 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....

  18. 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

    Analysis of the hydrophilic fraction of cranberry juice by reversed-phase HPLC using an Aqua LUNA column with diode array or MS detection revealed the presence of quinic acid, malic acid, shikimic acid, and citric acid. For the first time, two iridoid glucosides were found in the juice. The two...... 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...... carboxylic acids in cranberries was 2.67-3.57% (w/v), in lingonberries 2.27-3.05%, and in blueberries 0.35-0.75%. In lingonberries both iridoid glucosides were present, whereas only monotropein was present in blueberries....

  19. 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.

  20. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV Halides, Organotin (IV Halides and Thicyanates*

    Directory of Open Access Journals (Sweden)

    R. C. Aggarwal

    1981-04-01

    Full Text Available Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH, nicotinic acid hydrazide (NH or isonicotinic acide hydrazide (INH, x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV and IR spectral studies show that NH and INH coordiante through carbonyl oxygen and terminal nitrogen; and (PH through carbonyl oxygen and ring nitrogen in monoadducts. All the three isometric pyridine carboxylic acid hydrazides are coordinated through pyridine nitrogen alone in the di-adducts. Octahedral geometry has been proposed for mono-as well as di-adducts.

  1. Carboxylic acids in the hindgut of rats fed highly soluble inulin and Bifidobacterium lactis (Bb-12), Lactobacillus salivarius (UCC500) or Lactobacillus rhamnosus (GG)

    OpenAIRE

    Nilsson, Ulf; Nyman, Margareta

    2007-01-01

    Background Propionic and butyric acids are important nutrients for the mucosal cells and may therefore increase the nutritional status and reduce the permeability of the colonic mucosa. These acids have also been suggested to counteract diseases in the colon, e.g. ulcerative colitis and colon cancer. Different substrates lead to different amounts and patterns of carboxylic acids (CAs). Objective To study the effect of probiotics on CA formation in the hindgut of rats given inulin. Design The ...

  2. Study of Lewis Acid Promoting KBH_4 Reduce Carboxylic Acid Ester%Lewis酸促进KBH_4还原某些羧酸酯的研究

    Institute of Scientific and Technical Information of China (English)

    汪一波; 金召磊; 唐守万; 孙佰申; 潘富友; 高建荣

    2011-01-01

    Potassium borohydride reduction of some carboxylic esters into the corresponding alcohols by the Lewis acid was introduced.The structures were confirmed by 1HNMR,MS and IR,consistent with its structure and the target,and the yield of 37.5~68.5.%在Lewis酸的作用下,研究硼氢化钾将某些羧酸酯还原成相应的醇。其产物经1HNMR、MS和IR表征,其结构与目标物一致,收率在37.5~68.5之间。

  3. Synthesis and Crystal Structure of 4-(4,6-Dimethoxylpyrimidin-2-yl)-3-thiourea Carboxylic Acid Ethyl Ester

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yang; HUANG Jie; SONG Ji-Rong; REN Ying-Hui; XU Kang-Zhen

    2008-01-01

    4-(4,6-Dimethoxyl-pyrimidin-2-yl)-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine,potassium thiocyanate and methyl chloroformate in ethyl acetate.Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamidc at room temperature.The crystal structure was determined by X-ray diffraction analysis.Crystallographic data:C10H14N4O4S,Mr=286.31,monoclinic,space group C2/c with a=2.5309(3),b=0.67682(6),c=1.74237(19)nm,β=114.744(3)°,V=2.7106(5)nm3,Dc=1.403 g/cm3,μ=0.225mm-1,F(000)=1200,Z=8,R=0.0514 and wR=0.1529.

  4. Synthesis and Crystal Structure of 4-(4,6-dimethoxyl -pyrimidin-2-yl)-3-thiourea Carboxylic Acid Methyl Ester

    Institute of Scientific and Technical Information of China (English)

    HUANG Jie; SONG Ji-Rong; REN Ying-Hui; XU Kang-Zhen; MA Hai-Xia

    2006-01-01

    The title compound 4-(4,6-dimethoxylpyrimidin-2-yl)-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at the room temperature. The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis. Crystallographic data: C9H12N4O4S, Mr = 272.29, monoclinic, space group C2/m with a = 1.6672(3), b = 0.66383(12), c = 1.1617(2) nm, β = 109.275(2)°, V = 1.2136(4) nm3, Dc = 1.490 g/cm3, μ = 0.281 mm-1, F(000) = 568, Z = 4, R1 = 0.0341and wR2 = 0.1042.

  5. Synthesis, Fluorescence Properties, and Antiproliferative Potential of Several 3-Oxo-3H-benzo[f]chromene-2-carboxylic Acid Derivatives.

    Science.gov (United States)

    Fu, Xiao-Bo; Wang, Xian-Fu; Chen, Jia-Nian; Wu, De-Wen; Li, Ting; Shen, Xing-Can; Qin, Jiang-Ke

    2015-01-01

    In this study, two series of 3-oxo-3H-benzo[f]chromene-2-carboxylic acid derivatives (compounds 5a-i and 6a-g) were synthesized. Their in vitro proliferation inhibitory activities against the A549 and NCI-H460 human non-small cell lung cancer (NSCLC) cell lines were evaluated. Their photophysical properties were measured. Among these target compounds, 5e exhibited the strongest antiproliferative activity by inducing apoptosis, arresting cell cycle, and elevating intracellular reactive oxygen species (ROS) level, suggesting that it may be a potent antitumor agent. In addition, compound 6g with very low cytotoxicity, demonstrated excellent fluorescence properties, which could be used as an effective fluorescence probe for biological imaging. PMID:26473819

  6. Captan metabolism in humans yields two biomarkers, tetrahydrophthalimide (THPI) and thiazolidine-2-thione-4-carboxylic acid (TTCA) in urine.

    Science.gov (United States)

    Krieger, R I; Thongsinthusak, T

    1993-01-01

    Captan fungicide (N-(trichloromethylthio)-4-cyclohexene-1,2-dicarboximide) metabolism in two human volunteers rapidly yields THPI (tetrahydrophthalimide) and TTCA (thiazolidine-2-thione-4-carboxylic acid). The work was done to evaluate usefulness of TTCA and THPI as biomarkers of occupational exposure and to compare human and rat dermal absorption and metabolism. THPI in 12h urine ranged from MDL (5 ppb) to 640 ppb and was stable for at least one year. TTCA was also a stable metabolite, but the MDL was 50 ppb. THPI was detectable in urine for 72 hours following oral dosages of 1 mg/kg, but most was eliminated 0-24 h. No THPI was detectable in urine following application of a chloroform solution to hands, forearms, or inguinal region. Dermal absorption and metabolism of captan are substantially different in humans and rats.

  7. An anionic two-dimensional indium carboxylate framework derived from a pseudo 3-symmetric semi-flexible tricarboxylic acid

    Indian Academy of Sciences (India)

    Pratap Vishnoi; Alok Ch Kalita; Ramaswamy Murugavel

    2014-09-01

    Hydrothermal treatment of indium(III) nitrate with a flexible pseudo 3-symmetric tricarboxylic acid at 115°C for 5 days in DMF yields a new layered anionic indium carboxylate framework, [(CH3)2 NH2)][In(L)(HCOO)(DMF)] (1) (L = 2,4,6-tris[(4′-carboxyphenoxy)methyl]-1,3,5-trimethylbenzene), existing as two-dimensional sheets. The framework solid has been characterized by elemental analysis, FT-IR spectroscopy, TGA, PXRD and single crystal X-ray diffraction studies. DMF undergoes cleavage to dimethyl ammonium and formate ions, which are incorporated in the framework. A slipped stacking of the two dimensional sheets along -axis in 1 results in a drastic decrease in the anticipated large porosity of the framework.

  8. Effect of acute acid loading on acid-base and calcium metabolism

    DEFF Research Database (Denmark)

    Osther, Palle J

    2006-01-01

    OBJECTIVE: To investigate the acid-base and calcium metabolic responses to acute non-carbonic acid loading in idiopathic calcium stone-formers and healthy males using a quantitative organ physiological approach. MATERIAL AND METHODS: Five-h ammonium chloride loading studies were performed in 12 m...

  9. Ethylene-enhanced catabolism of ( sup 14 C)indole-3-acetic acid to indole-3-carboxylic acid in citrus leaf tissues. [Citrus sinensis

    Energy Technology Data Exchange (ETDEWEB)

    Sagee, O.; Riov, J.; Goren, J. (Hebrew Univ. of Jerusalem, Rehovot (Israel))

    1990-01-01

    Exogenous ({sup 14}C)indole-3-acetic acid (IAA) is conjugated in citrus (Citrus sinensis) leaf tissues to one major substance which has been identified as indole-3-acetylaspartic acid (IAAsp). Ethylene pretreatment enhanced the catabolism of ({sup 14}C)IAA to indole-3-carboxylic acid (ICA), which accumulated as glucose esters (ICGlu). Increased formation of ICGlu by ethylene was accompanied by a concomitant decrease in IAAsp formation. IAAsp and ICGlu were identified by combined gas chromatography-mass spectrometry. Formation of ICGlu was dependent on the concentration of ethylene and the duration of the ethylene pretreatment. It is suggested that the catabolism of IAA to ICA may be one of the mechanisms by which ethylene endogenous IAA levels.

  10. Utilization of oriented crystal growth for screening of aromatic carboxylic acids cocrystallization with urea

    Science.gov (United States)

    Przybyłek, Maciej; Ziółkowska, Dorota; Kobierski, Mirosław; Mroczyńska, Karina; Cysewski, Piotr

    2016-01-01

    The possibility of molecular complex formation in the solid state of urea with benzoic acid analogues was measured directly on the crystallite films deposited on the glass surface using powder X-ray diffractometry (PXRD). Obtained solid mixtures were also analyzed using Fourier transform infrared spectroscopy (FTIR). The simple droplet evaporation method was found to be efficient, robust, fast and cost-preserving approach for first stage cocrystal screening. Additionally, the application of orientation effect to cocrystal screening simplifies the analysis due to damping of majority of diffraction signals coming from coformers. During validation phase the proposed approach successfully reproduced both positive cases of cocrystallization (urea:salicylic acid and urea:4-hydroxy benzoic acid) as well as pairs of co-formers immiscible in the solid state (urea:benzoic acid and urea:acetylsalicylic acids). Based on validated approach new cocrystals of urea were identified in complexes with 3-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid and 3,5-dihydroxybenzoic acid. In all cases formation of multicomponent crystal phase was confirmed by the appearance of new reflexes on the diffraction patterns and FTIR absorption band shifts of O-H and N-H groups.

  11. AGGREGATION BEHAVIOR OF UNSATURATED CARBOXYLIC ACID SALTS OF CHITOSAN%壳聚糖不饱和羧酸盐聚集行为的研究

    Institute of Scientific and Technical Information of China (English)

    林宝凤; 黎演明; 周妤莲; 杜予民

    2011-01-01

    Five kinds of unsaturated carboxylic acid salts of chitosan were prepared by the semidry way including chitosan salicylate ( al ) , chitosan benzoate (a2) , chitosan cinnamate ( a3 ) , chitosan acrylate ( a4 ) and chitosan itaconate (a5). The products were characterized via FTIR and UV,the content of carboxylic acid in the unsaturated carboxylic acid salt of chitosan was determinated by the Kjeldahl method. The results showed that unsaturated carboxylic acid salts of chitosan were combined with salt bond between amino and carboxyl,the content of carboxylic acid in the unsaturated carboxylic acid salts was ranged from 40% to 70%. The crystalline morphology of these unsaturated carboxylic acid salts of chitosan were obtained by polarized optical microscopy. The results showed that the films of a2 and a5 obtained by a casting solvent vaporation technique had formed fractal crystal at 25℃ and RH = 65%. The crystalline morphology was closely related to the structures of unsaturated carboxylic acid salts of chitosan. The fractal crystal of a2 showed that the extendedmolecular chains were parallel to the long axis. The fractal crystal of a5 showed that the extended molecularchains were perpendicular to the long axis. The methods for controlling aggregation behavior of unsaturated carboxylic acid salts of chitosan had also been studied. It was feasible for the inter-conversion between aggregation and crystallization. The crystallization process of chitosan unsaturated carboxylic acid salts was explained by fractal theory, and the results showed that its aggregation behavior abide by the model of diffusions-limited aggregation.%以半干法制备了一系列壳聚糖不饱和羧酸盐--壳聚糖水杨酸盐(a1)、壳聚糖苯甲酸盐(a2)、壳聚糖肉桂酸盐(a3)壳聚糖丙烯酸盐(a4)和壳聚糖衣康酸盐(a5).用红外光谱和紫外光谱表征了该产品的结构,以凯氏定氮法测定了羧酸的结合量.结果表明壳聚糖和不饱和羧酸盐是

  12. Production of aliphatic carboxylic acids during the alkali catalysed decomposition of cellulose

    OpenAIRE

    Efhil, Mohamed

    2013-01-01

    The degradation of cellulosic materials under alkaline condition (sodium hydroxide) using High performance ion exclusion chromatography (HPIEC) Dionex ICS‐3000 to analyse the samples at different temperatures (at room, at 50 °C, at 90 °C), under atmosphere of N2 during 188 hours, by using acrylic acid as internal standard, resulted in complex mixture of compounds, including isosaccharinic acid. The retention time of aliphatic organic acids measured under the conditions outlined i...

  13. Long-chain carboxylic acids in pyrolysates of Green River kerogen

    Science.gov (United States)

    Kawamura, K.; Tannenbaum, E.; Huizinga, B. J.; Kaplan, I. R.

    1986-01-01

    Long-chain fatty acids (C10-C32), as well as C14-C21 isoprenoid acids (except for C18), have been identified in anhydrous and hydrous pyrolyses products of Green River kerogen (200-400 degrees C, 2-1000 hr). These kerogen-released fatty acids are characterized by a strong even/odd predominance (CPI: 4.8-10.2) with a maximum at C16 followed by lesser amounts of C18 and C22 acids. This distribution is different from that of unbound and bound geolipids extracted from Green River shale. The unbound fatty acids show a weak even/odd predominance (CPI: 1.64) with a maximum at C14, and bound fatty acids display an even/odd predominance (CPI: 2.8) with maxima at C18 and C30. These results suggest that fatty acids were incorporated into kerogen during sedimentation and early diagenesis and were protected from microbial and chemical changes over geological periods of time. Total quantities of fatty acids produced during heating of the kerogen ranged from 0.71 to 3.2 mg/g kerogen. Highest concentrations were obtained when kerogen was heated with water for 100 hr at 300 degrees C. Generally, their amounts did not decrease under hydrous conditions with increase in temperature or heating time, suggesting that significant decarboxylation did not occur under the pyrolysis conditions used, although hydrocarbons were extensively generated.

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

    OpenAIRE

    Kangani, Cyrous O.; Kelley, David E.

    2005-01-01

    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.

  15. Carboxylic Acid Ionophores as Probes of the Role of Calcium in Biological Systems

    Science.gov (United States)

    Reed, P. W.

    1983-01-01

    The biological effects of calcium ionophores are described, focusing on arachidonic acid oxygenation, and the formation of a number of oxygenated metabolites of arachidonic acid. These metabolites are involved in a number of bodily functions, and their production may be regulated by calcium.

  16. Synthesis of -acylurea derivatives from carboxylic acids and ,' -dialkyl carbodiimides in water

    Indian Academy of Sciences (India)

    Ali Ramazani; Fatemeh Zeinali Nasrabadi; Aram Rezaei; Morteza Rouhani; Hamideh Ahankar; Pegah Azimzadeh Asiabi; Sang Woo Joo; Katarzyna Ślepokura; Tadeusz Lis

    2015-12-01

    Reactions of benzoic acid derivatives and ()-cinnamic acid derivatives with , '-dialkyl carbodiimide proceed smoothly at room temperature and in neutral conditions to afford -acylurea derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions were observed.

  17. Modeling of the selective pertraction of carboxylic acids obtained by citric fermentation

    Directory of Open Access Journals (Sweden)

    Cascaval Dan

    2004-01-01

    Full Text Available Facilitated pertraction was applied for the selective separation of citric, maleic and succinic acids from a mixture obtained by citric fermentation. The pertraction equipment included a U-shaped cell containing 1,2-dichloro-ethane as the liquid membrane and Amberlite LA-2 as the carrier. The experimental data indicated that maleic and succinic acids can be initially selectively separated from citric acid, followed by the selectively separation of maleic acid from succinic acid. Using statistical analysis and a second order factorial experiment, two mathematical correlations describing the influence of the main process variables on pertraction selectivity were established. For both extraction systems, the considered variables controlled the extraction process to an extent of 92.9-99.9%, the carrier concentration inside the liquid membrane exhibiting the most important influence.

  18. A study of hydrogen-bond dynamics in carboxylic acids by NMR T1 measurements: isotope effects and hydrogen-bond length dependence

    Science.gov (United States)

    Agaki, T.; Imashiro, F.; Terao, T.; Hirota, N.; Hayashi, S.

    1987-08-01

    Proton (deuteron) transfer of hydrogen bonds in benzoic, glutaric and p-formylbenzoic acids was studied by proton (deuteron) T1 measurements. Deuteration of carboxylic protons was found to increase the barriers to classical proton jumping as well as quantum-mechanical tunneling. The former barriers increase as the hydrogen-bond distance increases.

  19. Drug Discovery Based on the Structure of FKBPs: Design, Synthesis and Evaluation of L-1, 4-Thiazane-3-carboxylic Acid Derivatives as Neuroimmunophilin Ligands

    Institute of Scientific and Technical Information of China (English)

    Ai Hua NIE; Jun Hai XIAO; Hong Ying LIU; Li Li WANG; Song LI

    2005-01-01

    Based on the structure of FK506, FKBP12 and calcineurin complex and the interactive characteristics of small molecular ligands with FKBPs, a series of L-1,4-thiazane-3-carboxylic acid derivatives as neuroimmunophilin ligands was designed and synthesized. The results of evaluation show that compound N308 has a great promise as a candidate of neuroprotective and neuroregenerative agent.

  20. 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

    -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...

  1. 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

    International Nuclear Information System (INIS)

    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)

  2. 二氧化碳作为羧化试剂用于羧酸及其衍生物的合成%Synthesis of Carboxylic Acids and Derivatives Using CO2 as Carboxylative Reagent

    Institute of Scientific and Technical Information of China (English)

    张文珍; 吕小兵

    2012-01-01

    The catalytic transformation of carbon dioxide into high value-added fine chemicals has attracted attention because this will make CO2 into an abundant,inexpensive,and renewable C1 feedstock.More than 20 reactions involving CO2 as a starting material have been developed in recent decades but their successful industrialization is limited.One type of reactions that is technologically viable is to use CO2 as a carboxylative reagent in the production of a wide range of carboxylic acids and derivatives.This review focused on transition metal-catalyzed reactions for the synthesis of various carboxylic acid and derivatives from CO2,by the carboxylation of carbon nucleophiles and C-H bonds and reactions of CO2 with unsaturated organic compounds (especially those with a carbon-carbon multiple bond).This review also included transition metal-free or organocatalytic reactions for the transformation of CO2 into carboxylic acid and derivatives.%二氧化碳是储量丰富、廉价易得且可再生的C1资源,将其催化转化成高附加值精细化学品的研究已经引起了人们的广泛关注.目前,虽然二氧化碳用作初始原料的反应已经工业化的很少,但过去几十年中仍有二十多个具有实际应用前景的二氧化碳参与的新反应被发现,其中以二氧化碳作为羧化试剂合成各种羧酸及其衍生物的反应为突出代表.本文综述了过渡金属催化合成羧酸及其衍生物的二氧化碳与多种碳亲核试剂、碳氢键以及碳碳多重键化合物的反应,并总结了无过渡金属参与或有机小分子催化条件下将二氧化碳转化成羧酸及其衍生物的反应.

  3. Synthesis of a New Polyoxometalate Loaded Stearic Acid Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Yong YANG; Lei ZHANG; Wei FAN; Xiao Hong WANG; Bin LI; Jing Fu LIU

    2004-01-01

    The stearic acid nanoparticles loaded polyoxometalate K6[γ-(CpTi)2SiW10O38][(CpTi)2SiW10] have been prepared and structurally characterized by elemental analysis, IR spectra.The particle size was estimated by transition electron microscope and zatesizer instrument. The result showed that the polyoxometalate retained the parent structure after encapsulation by stearic acid nanoparticles.

  4. Highly Efficient Esterification of an Equimolar Amount of Carboxylic Acids and Alcohols Catalyzed by ZrOCl2·8H2O

    Institute of Scientific and Technical Information of China (English)

    Sun Hong-Bin; Hua Ruimao; Yin Ying-Wu

    2004-01-01

    Esterification of carboxylic acids with alcohols is one of the most fundamental and useful transformations in organic synthesis. The most common catalysts are H2SO4 and TsOH. However,H2SO4 or TsOH-catalyzed esterification procedure has some problems such as corrosion, side reactions, difficulty in separation. Hence, recently, various solid acid catalysts such as ion-exchanged resins, molecular sieve, and heteropoly acids etc. have been employed for esterification reaction.However, the solid acid catalysts are usually not easily accessible and expensive In addition, for achieving the high yield of esters, it is usually to carry out the esterification reaction by addition of an excess of one of the reactants. Therefore it is still interesting to develop the high activity,cost-effective catalyst system.which is a commercially available and very cheap inorganic salt.The esterification was carried out in the presence of ZrOCl2. 8H2O (0.05 mol %) using equimolar amount of carboxylic acids and alcohols at room temperature or at 50℃. For example, the esterification of propionic acid with methanol at room temperature for 24 h gave methyl propionate in 81% GC yield. A higher yield of esters can be obtained by the removal of water azeotropically.The present esterification procedure has the following advantages:1) Esters can be obtained in high yield with the use of equimolar amount of carboxylic acids and alcohols.2) Esterification proceeds at room temperature, the catalyst system is suitable for the esterification of highly reactive carboxylic acids such as acrylic acid.3) It is easy to isolate and purify the esters, and the catalyst is recyclable. The complete reaction mixture becomes two phases at room temperature, the esters in the organic phase can be separated conveniently by decanting, and the catalyst in the water can be reused without any treatment.

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gayen, Pallab [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Sinha, Chittaranjan, E-mail: c_r_sinha@yahoo.com [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India)

    2012-09-15

    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{yields}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: Black-Right-Pointing-Pointer Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. Black-Right-Pointing-Pointer The process is sensitive to the environment of the photochrome and the solution. Black-Right-Pointing-Pointer The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. Black-Right-Pointing-Pointer The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. Black-Right-Pointing-Pointer The activation energy is less than these values when carried out in fresh solution only.

  7. Synthesis of Salicylic Acid Saccharide Carboxylate and Evaluation of Their Bioactivity%水杨酸糖酯制备及活性研究

    Institute of Scientific and Technical Information of China (English)

    武雪芬; 马金刚; 侯益民; 崔晓鸽; 孙德梅

    2011-01-01

    Objective: To prepare salicylic acid saccharide carboxylate, evaluate their irritation activity and biology activity. Methods: The salicylic acid saccharide carboxylate were prepared through carboxylic acid - organic alkali, and the acetylated salicylic glucopyranose tetraacetate was synthesized by sequential elution ;The structure of the products were identified by 1H -NMR and IR;The anticoagulant activity and anti - inflammatory activities were respectively evaluated by the cutting tail in mice and the models of mice ear edema induced by xylene,and the irritation activity was observed by tissue slices. Results:Fourβ -onfiguration salicylic acid saccharide carboxylate were prepared and three of them showed nearly the same bioactivities with aspirin in anticoagulant activity and anti - inflammation, and one of the products showed superior to their primary drug in anticoagulant activity;The irritation of the prepared products was less than the primary drug. Conclusion:The preparation of salicylic acid saccharide carboxylate could reduce the irritation of their corresponding primary drug.%目的:制备水杨酸糖酯,考察其刺激性和生物活性.方法:用羧酸有机碱法制备水杨酸糖酯;用1H-NMR和IR确认结构;用小鼠断尾法和小鼠耳肿胀法评价抗凝血活性和抗炎活性,组织切片法观察刺激性.结果:合成了4个β-构型的水杨酸糖酯,其中有3个的抗炎作用与阿司匹林相当,1个的抗凝血活性高于阿司匹林;合成物的刺激性均小于原药.结论:水杨酸糖酯类修饰可以降低刺激性.

  8. Dietary acid load and risk of hypertension : the Rotterdam Study

    NARCIS (Netherlands)

    Engberink, Marielle F.; Bakker, Stephan J. L.; Brink, Elizabeth J.; van Baak, Marleen A.; van Rooij, Frank J. A.; Hofman, Albert; Witteman, Jacqueline C. M.; Geleijnse, Johanna M.

    2012-01-01

    Background: Mild metabolic acidosis, which can be caused by diet, may result in elevated blood pressure (BP). Objective: The objective was to examine whether dietary acid load was associated with incident hypertension in a cohort of older Dutch adults from the Rotterdam Study. Design: The analyses i

  9. Dietary acid load and risk of hypertension: The Rotterdam study

    NARCIS (Netherlands)

    M.F. Engberink (Marielle); S.J.L. Bakker (Stephan); E.J. Brink (Elizabeth); M.A. van Baak (Marleen); F.J.A. van Rooij (Frank); A. Hofman (Albert); J.C.M. Witteman (Jacqueline); J.M. Geleijnse (Marianne)

    2012-01-01

    textabstractBackground: Mild metabolic acidosis, which can be caused by diet, may result in elevated blood pressure (BP). Objective: The objective was to examine whether dietary acid load was associated with incident hypertension in a cohort of older Dutch adults from the Rotterdam Study. Design: Th

  10. Dietary acid load and risk of hypertension: The Rotterdam study

    NARCIS (Netherlands)

    Engberink, M.F.; Bakker, S.J.L.; Brink, E.J.; Baak, M.A. van; Rooij, F.J.A. van; Hofman, A.; Witteman, J.C.M.; Geleijnse, J.M.

    2012-01-01

    Background: Mild metabolic acidosis, which can be caused by diet, may result in elevated blood pressure (BP). Objective: The objective was to examine whether dietary acid load was associated with incident hypertension in a cohort of older Dutch adults from the Rotterdam Study. Design: The analyses i

  11. Metabolic engineering of Saccharomyces cerevisiae for production of carboxylic acids: current status and challenges.

    Science.gov (United States)

    Abbott, Derek A; Zelle, Rintze M; Pronk, Jack T; van Maris, Antonius J A

    2009-12-01

    To meet the demands of future generations for chemicals and energy and to reduce the environmental footprint of the chemical industry, alternatives for petrochemistry are required. Microbial conversion of renewable feedstocks has a huge potential for cleaner, sustainable industrial production of fuels and chemicals. Microbial production of organic acids is a promising approach for production of chemical building blocks that can replace their petrochemically derived equivalents. Although Saccharomyces cerevisiae does not naturally produce organic acids in large quantities, its robustness, pH tolerance, simple nutrient requirements and long history as an industrial workhorse make it an excellent candidate biocatalyst for such processes. Genetic engineering, along with evolution and selection, has been successfully used to divert carbon from ethanol, the natural endproduct of S. cerevisiae, to pyruvate. Further engineering, which included expression of heterologous enzymes and transporters, yielded strains capable of producing lactate and malate from pyruvate. Besides these metabolic engineering strategies, this review discusses the impact of transport and energetics as well as the tolerance towards these organic acids. In addition to recent progress in engineering S. cerevisiae for organic acid production, the key limitations and challenges are discussed in the context of sustainable industrial production of organic acids from renewable feedstocks. PMID:19566685

  12. Synthesis of water soluble glycosides of pentacyclic dihydroxytriterpene carboxylic acids as inhibitors of α-glucosidase.

    Science.gov (United States)

    Xu, Jiancong; Nie, Xuliang; Hong, Yanping; Jiang, Yan; Wu, Guoqiang; Yin, Xiaoli; Wang, Chunrong; Wang, Xiaoqiang

    2016-04-01

    A series of compounds were synthesized by glycosylation of maslinic acid (MA) and corosolic acid (CA) with monosaccharides and disaccharides, and the structures of the derivatives were elucidated by standard spectroscopic methods including (1)H NMR, (13)C NMR and HRMS. The α-glucosidase inhibitory activities of all the novel compounds were evaluated in vitro. The solubility and inhibitory activity of α-glucosidase assays showed that the bis-disaccharide glycosides of triterpene acids possessed higher water solubility and α-glucosidase inhibitory activities than the bis-monosaccharide glycosides. Among these compounds, maslinic acid bis-lactoside (8e, IC50 = 684 µM) and corosolic acid bis-lactoside (9e, IC50 = 428 µM) had the best water solubility, and 9e exhibited a better inhibitory activity than acarbose (IC50 = 478 µM). However, most of glycosylated derivatives possessed lower inhibitory activities than the parent compounds, although their water solubility was enhanced obviously. Moreover, the kinetic inhibition studies indicated that 9e was a non-competitive inhibitor, and structure-activity relationships of the derivatives are also discussed. PMID:26974355

  13. Morphological control of layered double hydroxide through a biomimetic approach using carboxylic and sulfonic acids

    Directory of Open Access Journals (Sweden)

    Taishi Yokoi

    2015-09-01

    Full Text Available Layered double hydroxides (LDHs have intercalation properties and are used in various applications. The performances of the LDH materials can be improved by controlling crystal morphology. Morphology of inorganic crystals is controlled by organic molecules in biomineralization. Inspired by biomineralization, we investigated the effect of the addition of mono, di and triacids as morphological control agents on crystal morphology of LDH synthesized by the homogeneous precipitation method. Morphology of LDH was changed from hexagonal plate to stacked disc by addition of monoacids, namely acetic acid and methanesulfonic acid, in the reaction solution. Flower-shaped LDH crystals were formed in the presence of diacids and a triacid, namely succinic acid, 1,2-ethanedisulfonic acid and 1,2,3-propanetricarboxylic acid. We found that the morphology of the LDH crystals was controlled by the number of functional group on the morphological control agent rather than the type of functional group. These findings can contribute for the development of novel and functional LDH materials with precisely controlled morphology.

  14. 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.

  15. Effect of 1,10-phenanthroline aromaticity in carboxylic acids:1H NMR spectroscopy, GIAO calculations and thermodynamic properties

    Science.gov (United States)

    Machado, Camila M. B.; Santos, Vanessa F. C.; Belarmino, Marcia K. D. L.; França, José A. A.; Moura, Gustavo L. C.; Lima, Nathalia B. D.

    2016-08-01

    Hydrogen bonding represents a class of chemical interactions, which are directly responsible for several physical properties, such as: energetic stabilities, boiling points, vibrational modes, bond lengths, etc. In this article, we examine from the point of view of 1H NMR spectroscopy and GIAO calculations, the effects associated with the process of formation of the hydrogen bonds as they appear in the chemical shifts of the acidic hydrogens in the complexes between nitrogenated compounds, PHEN, BIPY and DIBIPY, and carboxylic acids, HOOCH, HOOCCH3 and HOOCC6H5. All computational simulations were performed using the quantum chemical methods B3LYP/6-31++G(d,p) and ωB97X-D/def2-TZVP. The 1H NMR spectroscopy results showed that, in both cases, the hydrogen nucleus of the OH group is the most affected in the process of hydrogen bond formation. For the complexes involving PHEN we observed that the hydrogen nucleus is more strongly shielded when compared with this signal in the corresponding complexes involving BIPY and DIBIPY.

  16. 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.

  17. Water-Soluble Poly(p-aryleneethynylene)s: A Sensor Array Discriminates Aromatic Carboxylic Acids.

    Science.gov (United States)

    Han, Jinsong; Wang, Benhua; Bender, Markus; Seehafer, Kai; Bunz, Uwe H F

    2016-08-10

    A chemical tongue consisting of 11 elements (four poly(p-aryleneethynylene)s (PAE) at pH 7 and pH 13, and seven electrostatic complexes formed from oppositely charged poly(p-aryleneethynylene)s at pH 7) discriminate 21 benzoic and phenylacetic acid derivatives in aqueous solution. The mechanism of discrimination is the fluorescence modulation of the PAEs, leading to quenching or fluorescence turn-on. The PAEs alone at both pH values and the tongue, consisting of the complexes only, discriminate the 21 acids with 92% (PAEs at pH 7), 95% (PAEs at pH 13), and 99% (complexes at pH 7) reliability after linear discriminant analysis (LDA). A sensor field with all 14 elements, according to LDA, discriminates all of the 21 acids with 100% accuracy. PMID:27415439

  18. 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…

  19. 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...

  20. Comparative characterization of the deamidation of carboxylic acid deamidated wheat gluten by altering the processing conditions.

    Science.gov (United States)

    Liao, Lan; Han, Xueyue; Chen, Lin-Ping; Ni, Li; Liu, Zhi-Bin; Zhang, Wen; Chen, Qing

    2016-11-01

    The physicochemical, structural and functional properties of citric-acid-deamidated wheat gluten at controlled degrees of deamidation (25%, 40% and 55%), which were obtained by using different acid concentrations (3.93×10(-5), 3.14×10(-3) and 2.36×10(-2)mol/L) and temperatures (70°C 2h, 90°C 1h and 110°C 40min), were compared. Various deamidation processing conditions leading to the same degree of deamidation resulted in proteins with different physicochemical and structural characteristics, as indicted by the degree of hydrolysis, Z-potential, surface hydrophobicity, particle size, SDS-PAGE results, SEC-HPLC results, intrinsic fluorescence and FTIR spectra. Agglomerative hierarchical clustering analysis and principal component analysis qualitatively indicated a significant effect of pH on protein deamidation. Three samples at 40% deamidation, which were produced by a moderate acid concentration, showed the best emulsifying and foaming properties. Processes conducted at greater than 90°C causing protein aggregation and at a high acid concentration rupturing peptide bonds, impaired protein quality. These findings demonstrated that a limited amount of H(+) could function well in the catalysis of the deamidation of amide groups without an excess of H(+), which hydrolyses peptide bonds in a stronger hydrothermal treatment. PMID:27211678

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

    Indian Academy of Sciences (India)

    Ranita Samanta; Shipra Kanaujia; C Malla Reddy

    2014-09-01

    One co-crystal and one salt of an antibacterial drug sulfathiazole with 4-aminobenzamide and 2,4-dinitrobenzoic acid have been synthesized. These new forms are characterized by single crystal X-ray diffraction, infrared spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In solid state, sulfathiazole preferentially adopts the imidine tautomeric form.

  2. Malic Acid Production by Saccharomyces cerevisiae: Engineering of Pyruvate Carboxylation, Oxaloacetate Reduction, and Malate Export

    NARCIS (Netherlands)

    Zelle, R.M.; De Hulster, E.; Van Winden, W.A.; De Waard, P.; Dijkema, C.; Winkler, A.A.; Geertman, J.M.; Van Dijken, J.P.; Pronk, J.T.; Van Maris, A.J.A.

    2008-01-01

    Malic acid is a potential biomass-derivable "building block" for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production

  3. Different geometrical arrangements in carboxylate coordination polymers of flexible dicarboxylic acid

    International Nuclear Information System (INIS)

    Dicarboxylate coordination polymers (1-5) of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II), respectively, derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid (L1H2) are synthesized and characterized. Depending on the coordination sites around the metal centers and coordination mode of the ligand, dimensionality of these polymers varies. The dicarboxylates adopt three spatial orientations: in-plane linear coordination, out-of-plane cis coordination and out-of-plane trans coordination mode. Both the cis and trans out-of-plane coordination modes are found to exist only if the ancillary ligand pyridine is coordinated to the metal ion. When the aquoligand coordinates the in-plane linear coordination mode of L1 predominates. The coordination polymers 4 and 5 show photoluminescence in solution. The dicarboxylate of (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid (L2H2) does not form coordination polymer under ambient conditions, but prefers to remain as uncoordinated anion providing hydrophobic confinement to hexa-aquometal(II) cation. Compound 3 crystallizes in P21 space group and it shows broadband ultra-violet fluorescence centered at 352.9 nm on focusing 632.8 nm He:Ne laser. - Graphical abstract: Different geometrical arrangements in coordination polymers derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid of metal ions Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) are presented. The (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid led to hexa-aquo cadmium(II) dicarboxylate. Highlights: → Structural and spectroscopic characterizations of five dicarboxylate coordination polymers of (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid with different metal ions are presented. → Different geometrical arrangements of coordination polymers stabilized in solid state are described. → Photoluminescence properties of the polymers are shown. → NLO property of a copper coordination polymer is described.

  4. 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, poxalic acid in fine 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.

  5. 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. PMID:26996381

  6. IR, Raman and SERS spectra of 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzene carboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Asha [Government Polytechnic Coll., Attingal, Kerala (India). Dept. of Physics; Raju, K. [University College, Trivandrum, Kerala (India). Dept. of Physics; Varghese, Hema Tresa [Fatima Mata National Coll., Kollam, Kerala (India). Dept. of Physics; Granadeiro, Carlos M.; Nogueira, Helena I. S. [University of Aveiro (Portugal). Centro de Investigacao em Materiais Ceramicos e Compositos (CICECO). Dept. of Chemistry; Panicker, C. Yohannan [TKM College of Arts and Science, Kollam, Kerala (India). Dept. of Physics]. E-mail: cyphyp@rediffmail.com

    2009-07-01

    2-(Methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylic acid was prepared by nucleophilic substitution. FT-IR and FT-Raman spectra of 2-(methoxycarbonylmethylsulfanyl)-3,5-dinitrobenzenecarboxylic acid were recorded and analyzed. Surface enhanced Raman scattering (SERS) spectrum was recorded on a silver colloid. The vibrational wavenumbers were computed by density functional theoretical (DFT) computations at the B3LYP/6-31G{sup *} level and they were found to be in good agreement with the experimental values. Significant metal-molecule interaction has been substantiated by the appearance of intense Ag-O mode in the SERS spectrum and this is indicative of the nearness of nitro and carbonyl group to the silver surface. SERS studies suggest a tilted orientation of the molecule at the metal surface. (author)

  7. Liquid-phase hydrogenation of aromatic carboxylic acids to cyclohexanecarboxylic ones on heterogeneous catalysts

    International Nuclear Information System (INIS)

    Results of theoratical and experimental studies in the field of liquid-phase hydrogenation of aromatic acids, n-nitrobenzoic in particular, were analyzed and generalized. Directions of hydrogenation on metal sodium, on nickel catalysts, platinum group metals were considered. Applied ruthenium catalysts feature the highest activity and selectivity. It is shown that specific surface of ruthenium and mass specific activity of catalyst increase in the series Ru/SiO2 < Ru/C

  8. Metabolic engineering of Saccharomyces cerevisiae for production of carboxylic acids: current status and challenges

    OpenAIRE

    Abbott, D.A.; Zelle, R.M.; Pronk, J T; van Maris, A. J. A.

    2009-01-01

    To meet the demands of future generations for chemicals and energy and to reduce the environmental footprint of the chemical industry, alternatives for petrochemistry are required. Microbial conversion of renewable feedstocks has a huge potential for cleaner, sustainable industrial production of fuels and chemicals. Microbial production of organic acids is a promising approach for production of chemical building blocks that can replace their petrochemically derived equivalents. Although Sacch...

  9. Facile Synthesis of Some Novel Pyrido[3', 2': 4, 5]thieno[2,3-b][1,4]thiazine-8-carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Arnd Ingendoh

    2007-03-01

    Full Text Available Model tetrahydropyrido[3',2':4,5]thieno[2,3-b][1,4]thiazines 9a-c were synthesized via reductive lactamization, using sodium dithionite, of the respective 2-[(carboxyalkylthio]-3-nitro-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylic acids 7a-c. The latter derivatives were made via interaction of 2-chloro-7-cyclopropyl-3-nitro-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylic acid (6 with each of α–mercaptoacetic, α-mercaptopropionic, and α-mercaptosuccinic acids and triethylamine in aqueous acetone at room temperature. The structures of 7a-7c and 9a-9c are supported by microanalytical and spectral (IR, MS, NMR data. Compounds 9a and 9c showed potent inhibitory activity against the IGROV1 (Ovarian Cancer cell line.

  10. Facile Synthesis of Some Novel Pyrido[3', 2': 4, 5]thieno[2,3-b][1,4]thiazine-8-carboxylic Acids

    OpenAIRE

    Arnd Ingendoh; Salim S Sabri; Jalal A Zahra; Mustafa M. El-Abadelah; Al-huniti, Mohammed H.

    2007-01-01

    Model tetrahydropyrido[3',2':4,5]thieno[2,3-b][1,4]thiazines 9a-c were synthesized via reductive lactamization, using sodium dithionite, of the respective 2-[(carboxyalkyl)thio]-3-nitro-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylic acids 7a-c. The latter derivatives were made via interaction of 2-chloro-7-cyclopropyl-3-nitro-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylic acid (6) with each of α–mercaptoacetic, α-mercaptopropionic, and α-mercaptosuccinic acids and triethylamine in...

  11. Morphological characterization of LiFePO{sub 4}/C composite cathode materials synthesized via a carboxylic acid route

    Energy Technology Data Exchange (ETDEWEB)

    Fey, George Ting-Kuo; Lu, Tung-Lin [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 (China)

    2008-04-01

    A new type of LiFePO{sub 4}/C composite surrounded by a web containing both amorphous and crystalline carbon phases was synthesized by incorporating malonic acid as a carbon source using a high temperature solid-state method. SEM, TEM/SAED/EDS and HRTEM were used to analyze surface morphology and confirmed for the first time that crystalline carbon was present in LiFePO{sub 4}/C composites. The composite was effective in enhancing the electrochemical properties such as capacity and rate capability, because its active component consists of nanometer-sized particles containing pores with a wide range of sizes. An EDS elemental map showed that carbon was uniformly distributed on the surface of the composite crystalline particles. TEM/EDS results clearly show a dark region that is LiFePO{sub 4} with a trace of carbon and a gray region that is carbon only. To evaluate the materials' electrochemical properties, galvanostatic cycling and conductivity measurements were performed. The best cell performance was delivered by the material coated with 60 wt.% malonic acid, which delivered first cycle discharge capacity of 149 mAh g{sup -1} at a C/5 rate and sustained 222 cycles at 80% of capacity retention. When carboxylic acid was used as a carbon source to produce LiFePO{sub 4}, overall conductivity increased from 10{sup -5} to 10{sup -4} S cm{sup -1}, since particle growth was prevented during the final sintering process. (author)

  12. Copper nanoparticles supported on permeable monolith with carboxylic acid surface functionality: Stability and catalytic properties under reductive conditions

    Energy Technology Data Exchange (ETDEWEB)

    Poupart, Romain; Le Droumaguet, Benjamin, E-mail: ledroumaguet@icmpe.cnrs.fr; Guerrouache, Mohamed; Carbonnier, Benjamin, E-mail: carbonnier@icmpe.cnrs.fr

    2015-08-01

    This work reported on the immobilization of copper metallic nanoparticles at the interface of mercaptosuccinic acid-functionalized N-acryloxysuccinimide-based monoliths. Upon photochemically-mediated free radical copolymerization of N-acryloxysuccinimide reactive monomer with ethylene glycol dimethacrylate cross-linker, reactive monoliths were obtained. Nucleophilic substitution of the N-hydroxysuccinimide moieties with allylamine, allowed for the synthesis of an olefin-functionalized monolith, as demonstrated by Raman spectroscopy. Mercaptosuccinic acid was anchored at the surface of the porous polymeric material through photochemically-driven thiol-ene “click” addition. In a final step, adsorption of copper nanoparticles at the surface of the resulting carboxylic acid functionalized monolith was achieved via two distinct pathways. It was either realized by percolation of a suspension of pre-formed copper nanoparticles through the capillary or by in situ reduction of Cu{sup (II)}Br{sub 2} salt solution preliminary flown through the monolith. After characterization of the resulting hybrids by scanning electron microscopy and energy-dispersive X-ray spectroscopy, investigations were further pursued regarding the catalytic behavior of such hybrid materials. The possibility to reduce 2-nitrophenol into the corresponding 2-aminophenol within a few minutes via a flow-through process inside the hybrid monolithic capillary was notably successfully demonstrated. - Graphical abstract: Display Omitted - Highlights: • Monolithic micro-reactors with surface immobilized copper nanoparticle for flow through catalytic processes. • Porous polymer-stabilized copper nanoparticles. • Photothiol-ene click chemistry for the effective surface functionalization of porous monolithic polymers. • Surface adsorption of copper nanoparticles through in-situ and ex-situ strategies.

  13. Ionomycin, a carboxylic acid ionophore, transports Pb(2+) with high selectivity.

    Science.gov (United States)

    Erdahl, W L; Chapman, C J; Taylor, R W; Pfeiffer, D R

    2000-03-10

    Studies utilizing phospholipid vesicle loaded with chelator/indicators for polyvalent cations show that ionomycin transports divalent cations with the selectivity sequence Pb(2+) > Cd(2+) > Zn(2+) > Mn(2+) > Ca(2+) > Cu(2+) > Co(2+) > Ni(2+) > Sr(2+). The selectivity of this ionophore for Pb(2+) is in contrast to that observed for A23178 and 4-BrA23187, which transport Pb(2+) at efficiencies that are intermediate between those of other cations. When the selectivity difference of ionomycin for Pb(2+) versus Ca(2+) was calculated from relative rates of transport, with either cation present individually and all other conditions held constant, a value of approximately 450 was obtained. This rose to approximately 3200 when both cations were present and transported simultaneously. 1 microM Pb(2+) inhibited the transport of 1 mM Ca(2+) by approximately 50%, whereas the rate of Pb(2+) transport approached a maximum at a concentration of 10 microM Pb(2+) when 1 mM Ca(2+) was also present. Plots of log rate versus log ionomycin or log Pb(2+) concentration indicated that the transporting species is of 1:1 stoichiometry, ionophore to Pb(2+), but that complexes containing an additional Pb(2+) may occur. The species transporting Pb(2+) may include H.IPb.OH, wherein ionomycin is ionized once and the presence of OH(-) maintains charge neutrality. Ionomycin retained a high efficiency for Pb(2+) transport in A20 B lymphoma cells loaded with Indo-1. Both Pb(2+) entry and efflux were observed. Ionomycin should be considered primarily as an ionophore for Pb(2+), rather than Ca(2+), of possible value for the investigation and treatment of Pb(2+) intoxication. PMID:10702273

  14. Study on the Retention Behavior of Aromatic Carboxylic and Sulfonic acid on a New Anion Exchange Column

    Institute of Scientific and Technical Information of China (English)

    SHI,Ya-Li; CAI,Ya-Qi; MOU,Shi-Fen

    2008-01-01

    Ion chromatography (IC) has gradually developed into a preferred method for the determination of inorganic anions. And in recent years some low molecular aliphatic acid can be also separated in the ion exchange column with the development of stationary phase. But for the determination of aromatic ionic compounds there are some problems. The aromatic anions show enhanced retention due to interaction with the π electrons of the aromatic backbone. Although the addition of an organic modifier can alleviate the difficulty, it is not the ultimate solution.IonPac AS20 column was developed using a unique polymer bonding technology and its substrate coating is aliphatic backbone. The polymer is completely free of any π electron-containing substituents in the AS20 column. In this paper, the retention behavior of aromatic carboxylic and sulfonic acid on two hydroxide-selective columns,IonPac AS11-HC, AS16, and the new column AS20 was also studied. The result showed that the retentions of ten compounds on three columns were different with each other because of their different column characteristics.Among them 4-chlorobenzene sulfonic acid, 3,5-dihydric benzoic acid and salicylic acid obviously exhibited the weakest retention on the IonPac AS20. It was showed that π-π bond function between anion and stationary phases was weakened in AS20 column because its polymer was completely free of any π electron-containing substituents.So in this paper the AS20 was selected as an analytical column to separate ten aromatic ionic compounds, fumaric acid with conjugate bond included. The retention behavior, separation of the ten compounds and effect of temperature on their retention in the anion-exchange column AS20 (2 mm) were studied. The result showed that those compounds could be separated with each other when running in gradient program and the organic modifier was unnecessary during the separation. So it is showed that AS20 column can be used as a separating column because its

  15. 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...

  16. Spectroscopic studies on sidewall carboxylic acid functionalization of multi-walled carbon nanotubes with valine.

    Science.gov (United States)

    Deborah, M; Jawahar, A; Mathavan, T; Dhas, M Kumara; Benial, A Milton Franklin

    2015-03-15

    The valine functionalized multi-walled carbon nanotubes (MWCNTS) were prepared and characterized by using XRD, UV-Vis, FT-IR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (002) intensity was observed for valine functionalized MWCNTs compared with oxidized MWCNTs, which is likely due to sample purification by acid washing. UV-Vis study shows the formation of valine functionalized MWCNTs. FT-IR study confirms the presence of functional groups of oxidized MWCNTs and valine functionalized MWCNTs. The ESR line shape analysis indicates that the observed EPR line shape is a Gaussian line shape. The g-values indicate that the systems are isotropic in nature. The morphology study was carried out for oxidized MWCNTs and valine functionalized MWCNTs by using SEM. The EDX spectra revealed that the high purity of oxidized MWCNTs and valine functionalized MWCNTs. The functionalization has been chosen because, functionalization of CNTs with amino acids makes them soluble and biocompatible. Thus, they have potential applications in the field of biosensors and targeted drug delivery.

  17. Different geometrical arrangements in carboxylate coordination polymers of flexible dicarboxylic acid

    Science.gov (United States)

    Deka, Himangshu; Sarma, Rupam; Kumari, Satchi; Khare, Alika; Baruah, Jubaraj B.

    2011-07-01

    Dicarboxylate coordination polymers ( 1- 5) of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II), respectively, derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid ( L1H2) are synthesized and characterized. Depending on the coordination sites around the metal centers and coordination mode of the ligand, dimensionality of these polymers varies. The dicarboxylates adopt three spatial orientations: in-plane linear coordination, out-of-plane cis coordination and out-of-plane trans coordination mode. Both the cis and trans out-of-plane coordination modes are found to exist only if the ancillary ligand pyridine is coordinated to the metal ion. When the aquoligand coordinates the in-plane linear coordination mode of L1 predominates. The coordination polymers 4 and 5 show photoluminescence in solution. The dicarboxylate of (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid ( L2H2) does not form coordination polymer under ambient conditions, but prefers to remain as uncoordinated anion providing hydrophobic confinement to hexa-aquometal(II) cation. Compound 3 crystallizes in P2 1 space group and it shows broadband ultra-violet fluorescence centered at 352.9 nm on focusing 632.8 nm He:Ne laser.

  18. Spectroscopic studies on sidewall carboxylic acid functionalization of multi-walled carbon nanotubes with valine

    Science.gov (United States)

    Deborah, M.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

    2015-03-01

    The valine functionalized multi-walled carbon nanotubes (MWCNTS) were prepared and characterized by using XRD, UV-Vis, FT-IR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (0 0 2) intensity was observed for valine functionalized MWCNTs compared with oxidized MWCNTs, which is likely due to sample purification by acid washing. UV-Vis study shows the formation of valine functionalized MWCNTs. FT-IR study confirms the presence of functional groups of oxidized MWCNTs and valine functionalized MWCNTs. The ESR line shape analysis indicates that the observed EPR line shape is a Gaussian line shape. The g-values indicate that the systems are isotropic in nature. The morphology study was carried out for oxidized MWCNTs and valine functionalized MWCNTs by using SEM. The EDX spectra revealed that the high purity of oxidized MWCNTs and valine functionalized MWCNTs. The functionalization has been chosen because, functionalization of CNTs with amino acids makes them soluble and biocompatible. Thus, they have potential applications in the field of biosensors and targeted drug delivery.

  19. Effect of different carboxylic acids in cyclodextrin functionalization of cellulose nanocrystals for prolonged release of carvacrol.

    Science.gov (United States)

    Castro, D O; Tabary, N; Martel, B; Gandini, A; Belgacem, N; Bras, J

    2016-12-01

    Current investigations deal with new surface functionalization strategy of nanocrystalline cellulose-based substrates to impart active molecule release properties. In this study, cellulose nanocrystals (CNC) were surface-functionalized with β-cyclodextrin (β-CD) using succinic acid (SA) and fumaric acid (FA) as bridging agents. The main objective of this surface modification performed only in aqueous media was to obtain new active materials able to release antibacterial molecules over a prolonged period of time. The reactions were conducted by immersing the CNC film into a solution composed of β-CD, SA and FA, leading to CNC grafting. The materials were characterized by infrared spectroscopy (FT-IR), Quartz crystal microbalance-dissipation (QCM-D), AFM and phenolphthalein (PhP) was used to determine the efficiency of CNC grafting with β-CD. The results indicated that β-CD was successfully attached to the CNC backbone through the formation of ester bonds. Furthermore, carvacrol was entrapped by the attached β-CD and a prolonged release was confirmed. In particular, CNC grafted to β-CD in the presence of FA was selected as the best solution. The antibacterial activity and the controlled release were studied for this sample. Considerably longer bacterial activity against B. subtilis was observed for CNC grafted to β-CD compared to CNC and CNC-FA, confirming the promising impact of the present strategy. PMID:27612798

  20. 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.

  1. Acrylic acid-allylpolyethoxy carboxylate copolymer dispersant for calcium carbonate and iron(III) hydroxide scales in cooling water systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guangqing; Huang, Jingyi; Zhou, Yuming; Yao, Qingzhao; Ling, Lei; Zhang, Peixin; Fu, Change [Southeast Univ., Nanjing (China). School of Chemistry and Chemical Engineering; Wu, Wendao; Sun, Wei; Hu, Zhengjun [Jianghai Chemical Co., Ltd., Changzhou (China)

    2012-05-15

    A novel environmentally friendly type of calcium carbonate and iron(III) scale inhibitor (ALn) was synthesized. The anti-scale property of the Acrylic acid-allylpolyethoxy carboxylate copolymer (AA-APELn or ALn) towards CaCO{sub 3} and iron(III) in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate and iron(III) inhibition increase with increasing the degree of polymerization of ALn from 5 to 15, and the dosage of ALn plays an important role on calcium carbonate and iron(III)-inhibition. The effect on formation of CaCO{sub 3} was investigated with a combination of scanning electronic microscopy (SEM), Transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis and Fourier transform infrared spectrometer, respectively. The results showed that the ALn copolymer not only influences calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO{sub 3} in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the ALn copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol (PEG) are the fundamental impetus to restrain the formation of the scale in cooling water systems. (orig.)

  2. 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.

  3. DFT modeling and spectroscopic study of metal ligand bonding in La(III) complex of coumarin-3-carboxylic acid

    Science.gov (United States)

    Mihaylov, Tz.; Trendafilova, N.; Kostova, I.; Georgieva, I.; Bauer, G.

    2006-09-01

    The binding mode of coumarin-3-carboxylic acid (HCCA) to La(III) is elucidated at experimental and theoretical level. The complexation ability of the deprotonated ligand (CCA -) to La(III) is studied using elemental analysis, DTA and TGA data as well as FTIR, 1H NMR and 13C NMR spectra. The experimental data suggest the complex formula La(CCA) 2(NO 3)(H 2O) 2. B3LYP, BHLYP, B3P86, B3PW91, PW91P86 and MPW1PW91 functionals are tested for geometry and frequency calculations of the neutral ligand and all of them show bond length deviations bellow 1%. B3LYP/6-31G(d) level combined with large quasi-relativistic effective core potential for lanthanum is selected to describe the molecular, electronic and vibrational structures as well as the conformational behavior of HCCA, CCA - and La-CCA complex. The metal-ligand binding mode is predicted through molecular modeling and energy estimation of different La-CCA structures. The calculated atomic charges and the bonding orbital polarizations point to strong ionic metal-ligand bonding in La-CCA complex and insignificant donor acceptor interaction. Detailed vibrational analysis of HCCA, CCA - and La(CCA) 2(NO 3)(H 2O) 2 systems based on both calculated and experimental frequencies confirms the suggested metal-ligand binding mode.

  4. The Effect of Phenazine-1-Carboxylic Acid on the Morphological, Physiological, and Molecular Characteristics of Phellinus noxius.

    Science.gov (United States)

    Huang, Huazhi; Sun, Longhua; Bi, Keke; Zhong, Guohua; Hu, Meiying

    2016-05-11

    In this study, the effect of phenazine-1-carboxylic acid (PCA) on morphological, physiological, and molecular characteristics of Phellinus noxius has been investigated, and the potential antifungal mechanism of PCA against P. noxius was also explored. The results revealed that PCA showed in vitro antifungal potential against P. noxius and completely inhibited P. noxius hyphae at concentrations >40 μg/mL. PCA inhibited both mycelial growth and the loss of mycelial biomass in vitro in a dose-dependent manner. Morphological changes in PCA-treated P. noxius hyphae, such as irregularly swollen mycelia as well as short hyphae with increased septation and less branching, were observed by optical microscopy. The intracellular reactive oxygen species (ROS) levels were significantly increased in PCA-treated P. noxius cells as compared to control groups. Induced hyperpolarization of the mitochondrial membrane potential (MMP), repressed superoxide dismutase (SOD) activity and up-regulated gene expression of seven tested genes were also found in PCA-treated P. noxius groups. Thus, the present results suggested that the mechanism of action of PCA against P. noxius might be attributed to direct damage of mycelium and high intracellular ROS production, and indirect induction of genes involved in cell detoxification, oxidation-reduction process, and electron transport of the respiratory chain.

  5. The Effect of Phenazine-1-Carboxylic Acid on the Morphological, Physiological, and Molecular Characteristics of Phellinus noxius

    Directory of Open Access Journals (Sweden)

    Huazhi Huang

    2016-05-01

    Full Text Available In this study, the effect of phenazine-1-carboxylic acid (PCA on morphological, physiological, and molecular characteristics of Phellinus noxius has been investigated, and the potential antifungal mechanism of PCA against P. noxius was also explored. The results revealed that PCA showed in vitro antifungal potential against P. noxius and completely inhibited P. noxius hyphae at concentrations >40 μg/mL. PCA inhibited both mycelial growth and the loss of mycelial biomass in vitro in a dose-dependent manner. Morphological changes in PCA-treated P. noxius hyphae, such as irregularly swollen mycelia as well as short hyphae with increased septation and less branching, were observed by optical microscopy. The intracellular reactive oxygen species (ROS levels were significantly increased in PCA-treated P. noxius cells as compared to control groups. Induced hyperpolarization of the mitochondrial membrane potential (MMP, repressed superoxide dismutase (SOD activity and up-regulated gene expression of seven tested genes were also found in PCA-treated P. noxius groups. Thus, the present results suggested that the mechanism of action of PCA against P. noxius might be attributed to direct damage of mycelium and high intracellular ROS production, and indirect induction of genes involved in cell detoxification, oxidation-reduction process, and electron transport of the respiratory chain.

  6. 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.

  7. The cytotoxicity of benzaldehyde nitrogen mustard-2-pyridine carboxylic acid hydrazone being involved in topoisomerase IIα inhibition.

    Science.gov (United States)

    Fu, Yun; Zhou, Sufeng; Liu, Youxun; Yang, Yingli; Sun, Xingzhi; Li, Changzheng

    2014-01-01

    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 Fe(2+) 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 Fe(2+) 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.

  8. Sorption of uranyl(VI) cations on suspended silicate: effects of N-donor ligands, carboxylic acids, organic cosolvents, and metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, P.N.; Choppin, G.R. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry

    2007-07-01

    Sorption of uranyl ion, UO{sub 2}{sup 2+}, on silicate particles (3.00g/L) was studied in sodium perchlorate solution as a function of pcH and ionic strength at 298 K. The effects of different ligands (e.g., N-donors, carboxylic acids) on the uranyl sorption were investigated. At I = 0.20 M (NaClO{sub 4}), uranyl sorption on silicate increased from ca. 6% (pcH 3.0) to ca. 99% (at pcH 6.5), above which a small decrease was observed. A synergistic enhancement in uranyl sorption was observed in the presence of N-donor ligands such as 1,10-phenanthroline and ethylenediamine in the pcH range 3 to 4.5 as compared to that in the absence of ligands. Carboxylic acids inhibited the sorption in the order: citric acid > malonic acid > nitrilotriacetic acid > iminodiacetic acid > sulfosalicylic acid > succinic acid > glycolic acid. The presence of organic cosolvents such as dimethylsulfoxide, glycerol and tetrahydrofuran had no significant influence on the uranyl sorption profile. Uranyl sorption decreased marginally in the presence of 1.00 x 10{sup -3} M Eu(III). (orig.)

  9. Trimethylglycine complexes with carboxylic acids and HF: solvation by a polar aprotic solvent.

    Science.gov (United States)

    Guo, Jing; Koeppe, Benjamin; Tolstoy, Peter M

    2011-02-14

    A series of strong H-bonded complexes of trimethylglycine, also known as betaine, with acetic, chloroacetic, dichloroacetic, trifluoroacetic and hydrofluoric acids as well as the homo-conjugated cation of betaine with trifluoroacetate as the counteranion were investigated by low-temperature (120-160 K) liquid-state NMR spectroscopy using CDF(3)/CDF(2)Cl mixture as the solvent. The temperature dependencies of (1)H NMR chemical shifts are analyzed in terms of the solvent-solute interactions. The experimental data are explained assuming the combined action of two main effects. Firstly, the solvent ordering around the negatively charged OHX region of the complex (X = O, F) at low temperatures, which leads to a contraction and symmetrisation of the H-bond; this effect dominates for the homo-conjugated cation of betaine. Secondly, at low temperatures structures with a larger dipole moment are preferentially stabilized, an effect which dominates for the neutral betaine-acid complexes. The way this second contribution affects the H-bond geometry seems to depend on the proton position. For the Be(+)COO(-)···HOOCCH(3) complex (Be = (CH(3))(3)NCH(2)-) the proton displaces towards the hydrogen bond center (H-bond symmetrisation, O···O contraction). In contrast, for the Be(+)COOH···(-)OOCCF(3) complex the proton shifts further away from the center, closer to the betaine moiety (H-bond asymmetrisation, O···O elongation). Hydrogen bond geometries and their changes upon lowering the temperature were estimated using previously published H-bond correlations. PMID:21132169

  10. Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Octavian Croitoru

    2015-01-01

    Full Text Available A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid : acetonitrile : methanol with flow rate of 1 mL·min−1. Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008–2 μg·mL−1 for clopidogrel, 0.01–4 μg·mL−1 for its carboxylic acid metabolite, and 0.005–2.5 μg·mL−1 for atorvastatin. The results of accuracy (as recovery with ibuprofen as internal standard were in the range of 96–98% for clopidogrel, 94–98% for its carboxylic acid metabolite, and 90–99% for atorvastatin, respectively.

  11. 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.

  12. 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).

  13. Synthesis and crystal structure of Cu(II and Co(II complexes with 1,3-dimethyl-pyrazole-5-carboxylic acid ligand

    Directory of Open Access Journals (Sweden)

    Jaćimović Željko K.

    2015-01-01

    Full Text Available In the reaction of 1,3-dimethyl-pyrazole-5-carboxylic acid (HL with M(OAc2•4H2O, (M = Cu, Co two novel complexes have been prepared, square-planar [CuL2(H2O2] and octahedral [CoL2(MeOH4]. The crystal structures have been determined by single-crystal X-ray diffraction. In both complexes the deprotonated acid displays monodentate coordination to the metal ions. According to the results of CSD survey this is the first structural report on the metal complexes with N1-substituted pyrazole-5-carboxylic ligand. [Projekat Ministarstva nauke Republike Srbije, br. 172014 i br. 172035

  14. 4,5-Diarylisoxazol-3-carboxylic acids: A new class of leukotriene biosynthesis inhibitors potentially targeting 5-lipoxygenase-activating protein (FLAP).

    Science.gov (United States)

    Banoglu, Erden; Çelikoğlu, Erşan; Völker, Susanna; Olgaç, Abdurrahman; Gerstmeier, Jana; Garscha, Ulrike; Çalışkan, Burcu; Schubert, Ulrich S; Carotti, Andrea; Macchiarulo, Antonio; Werz, Oliver

    2016-05-01

    In this article, we report novel leukotriene (LT) biosynthesis inhibitors that may target 5-lipoxygenase-activating protein (FLAP) based on the previously identified isoxazole derivative (8). The design and synthesis was directed towards a subset of 4,5-diaryl-isoxazole-3-carboxylic acid derivatives as LT biosynthesis inhibitors. Biological evaluation disclosed a new skeleton of potential anti-inflammatory agents, exemplified by 39 and 40, which potently inhibit cellular 5-LO product synthesis (IC50 = 0.24 μM, each) seemingly by targeting FLAP with weak inhibition on 5-LO (IC50 ≥ 8 μM). Docking studies and molecular dynamic simulations with 5-LO and FLAP provide valuable insights into potential binding modes of the inhibitors. Together, these diaryl-isoxazol-3-carboxylic acids may possess potential as leads for development of effective anti-inflammatory drugs through inhibition of LT biosynthesis. PMID:26922224

  15. Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers.

    Science.gov (United States)

    Cho, M J; Adson, A; Kezdy, F J

    1990-04-01

    Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37 degrees C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by [14C]CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the "unstirred" boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier.

  16. Hydroxy, carboxylic and amino acid functionalized superparamagnetic iron oxide nanoparticles: Synthesis, characterization and in vitro anti-cancer studies

    Indian Academy of Sciences (India)

    Dilaveez Rehana; Azees Khan Haleel; Aziz Kalilur Rahiman

    2015-07-01

    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, VSM, SEM, TEM and thermal analysis. Both bare and coated magnetites were of cubic spinel structure and spherical in shape. All the magnetite nanoparticles showed superparamagnetic behaviour with high saturated magnetization. In vitro cytotoxicity test of bare and coated nanoparticles was performed using adenocarcinoma cells, A549. Cell viability of bare and L-arginine coated magnetite nanoparticles showed IC50 value of 31.2 g/mL proving the compatibility of nanocarriers when compared to others. Hence, L-arginine coated nanoparticles were used for loading the drug paclitaxel and the observed IC50 value (7.8 g/mL) shows its potent anti-proliferative effect against A549 lung cancer cell lines. Thus, it can be speculated that the drug paclitaxel loaded L-arginine coated nanoparticles could be used as an effective drug carrier for the destruction of cancer cells.

  17. Conformation Analysis and Comparison of Epristeride(17β-N-t-Butylcarboxamide-androst-3,5-diene-3-carboxylic Acid) and Its Analogs

    Institute of Scientific and Technical Information of China (English)

    YAO Li-xin

    2005-01-01

    Conformations of Epristeride(17-β-N-t-butylcarboxamide-androst-3,5-diene-3-carboxylic acid) and its analogs were analyzed with the random search method and compared by means of the methods for steroid conformers, Connolly surfaces, dihedral angles, and molecular accessibility probes with protons, hydroxyl and methyl groups contained simultaneously. Analog d is different from others, which is in accordance with the preliminary clinical trial results under double blind conditions.

  18. Self-assembly of monolayers of aromatic carboxylic acid molecules on silver and copper modified gold surfaces at the liquid-solid interface

    OpenAIRE

    Aitchison, Hannah

    2015-01-01

    Exploiting coordination bonding of aromatic carboxylic acids at metal surfaces, this thesis explores new directions in the design and application of self-assembled monolayers (SAMs). The SAMs are investigated using a multi-technique approach comprising of a complementary combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. In addition, the X-ray standing wave technique (XSW) was used to ...

  19. VO(acac)2 catalyzed condensation of o-phenylenediamine with aromatic carboxylic acids/aldehydes under microwave radiation affording benzimidazoles

    Institute of Scientific and Technical Information of China (English)

    Madhudeepa Dey; Krishnajyoti Deb; Siddhartha Sankar Dhar

    2011-01-01

    Vanadyl acetylacetonate, VO(acac)2, has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition. The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents. The benzimidazoles were obtained in quick time with high yields.

  20. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO_2 – The reduction chemistry of carboxylic acids and derivatives as bent CO_2 surrogates

    OpenAIRE

    Luca, Oana R.; Fenwick, Aidan Q.

    2015-01-01

    The present review covers organic transformations involved in the reduction of CO_2 to chemical fuels. In particular, we focus on reactions of CO_2 with organic molecules to yield carboxylic acid derivatives as a first step in CO_2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO_2 reactivity from organic chemistry, organocatalysis, surface science and elect...

  1. 6-Substituted 2-Oxo-2h-1-Benzopyran-3-Carboxylic Acid Derivatives in a New Approach of the Treatment of Cancer Cell Invasion and Metastasis

    OpenAIRE

    Kempen, I; Hemmer, Marc; Counerotte, Stéphane; Pochet, L.; De Tullio, Pascal; Foidart, Jean-Michel; Blacher, Silvia; Noël, Agnès; Frankenne, Francis; Pirotte, Bernard

    2008-01-01

    Novel 6-substituted 2-oxo-2H-1-benzopyran-3-carboxylic acid derivatives were synthesized and their potency in reducing the invasive behaviour of HT 1080 fibrosarcoma cells was evaluated. Structure-activity relationships were deduced from biological results and will be used in further design of new active compounds. In particular, the acetoxymethyl substituent found at the 6-position of previously described active compounds can be replaced by an acetamidomethyl substituent without loss of pote...

  2. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    OpenAIRE

    K.Ramesh; S. Shylaja; K. C. Rajanna; P. Giridhar Reddy; P. K. Saiprakash

    2013-01-01

    Polyethylene glycols (PEGs) were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN) in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours...

  3. A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

    OpenAIRE

    Christian Eidamshaus; Roopender Kumar; Bera, Mrinal K; Hans-Ulrich Reissig

    2011-01-01

    A practical approach to highly functionalized 4-hydroxypyridine derivatives with stereogenic side chains in the 2- and 6-positions is described. The presented two-step process utilizes a multicomponent reaction of alkoxyallenes, nitriles and carboxylic acids to provide β-methoxy-β-ketoenamides which are transformed into 4-hydroxypyridines in a subsequent cyclocondensation. The process shows broad substrate scope and leads to differentially substituted enantiopure pyridines in good t...

  4. Four-component synthesis of 1,3,4-oxadiazole derivatives from N-isocyaniminotriphenylphosphorane, aromatic carboxylic acids, aromatic bis-aldehydes, and secondary amines

    OpenAIRE

    Ramazani, Ali; Karimi, Zahra; SOULDOZI, Ali; AHMADI, Yavar

    2012-01-01

    The 1:1 iminium intermediate generated by the addition of a secondary amine to aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) is trapped by the N-isocyaniminotriphenylphosphorane in the presence of a aromatic carboxylic acid derivative, which leads to the formation of corresponding iminophosphorane intermediate. Then disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediates. The reactions were ...

  5. One-pot synthesis of fully substituted 1,3,4-oxadiazole derivatives from aromatic carboxylic acids, cyclobutanone and N-isocyaniminotriphenylphosphorane

    OpenAIRE

    HOLAGH, Mohsen VALIZADEH; MAHARRAMOV, Abel Mohammadali oglu

    2012-01-01

    Reactions of N-isocyaniminotriphenylphosphorane with cyclobutanone in the presence of aromatic (or heteroaromatic) carboxylic acids proceeded smoothly at room temperature and in neutral conditions to afford sterically congested 1-(5-aryl-1,3,4-oxadiazol-2-yl)- 1-cyclobutanol derivatives in high yields. The reaction proceeded smoothly and cleanly under mild conditions and no side reactions were observed. The structures of the products were deduced from their IR, 1HNMR, and 13CNMR spec...

  6. First total syntheses of aeruginosin 298-A and aeruginosin 298-B, based on a stereocontrolled route to the new amino acid 6-hydroxyoctahydroindole-2-carboxylic acid.

    Science.gov (United States)

    Valls, N; López-Canet, M; Vallribera, M; Bonjoch, J

    2001-08-17

    The first total syntheses of aeruginosin 298-A (1) and aeruginosin 298-B (3) are described. The syntheses of the alternative putative structures 2 and 4 were also accomplished. The key common strategic element is the stereo-controlled synthesis of (2S,3aS,6R,7aS)-6-hydroxyoctahydroindole-2-carboxylic acid (L-Choi, 5) from L-tyrosine. The synthesis of this new bicyclic alpha-amino acid, which is the core of aeruginosins, involves Birch reduction of O-methyl-L-tyrosine (6) and aminocyclization of the resulting dihydroanisole 7 in acid medium, followed by N-benzylation to give the diastereoisomers 12 and 13. Upon acid treatment with HCl-MeOH, the last two produce an equilibrium mixture in which the endo isomer 13 significantly predominates. Hydrogenation of 13 in the presence of (Boc)2O gives 16, which on reduction with LS-Selectride furnishes the alcohol 22, a protected L-Choi. Successive couplings of 22 with D-leucine, protected (R)-(4-hydroxyphenyl)lactic acid, and L-arginine fragments, followed by reduction to the argininol level and a deprotection end step complete the synthetic sequence to produce aeruginosin 298-A (1). Spectral comparison showed that peptide 2, with the structure previously proposed for aeruginosin 298-A, was different from the natural product. However, synthetic 1 was found to be identical to the isolated natural sample of aeruginosin 298-A. These results unequivocally establish that the absolute stereochemistry of aeruginosin 298-A, formerly assigned incorrectly, is D-Hpla-D-Leu-L-Choi-L-Argol, as shown by structure 1. Aeruginosin 298-B was also synthesized and shown to be a mixture of rotamers of D-Hpla-D-Leu-L-ChoiNH2 (3), rather than an epimeric mixture of 3 and the L-Leu-incorporating 4. PMID:11560314

  7. Biodistribution and human dosimetry of enantiomer-1 of the synthetic leucine analog anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Nye, Jonathon A., E-mail: jnye@emory.edu; Jarkas, Nashwa; Schuster, David M.; Savir-Baruch, Bital; Voll, Ronald J.; Camp, Vernon M.; Goodman, Mark M.

    2011-10-15

    Introduction: The enantiomerically enriched (ee=90%, enantiomer 1) synthetic amino acid (R,S)-anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid (anti-2-[{sup 18}F]FACPC-1) accumulates in malignant cells by elevated transport through the sodium-independent system-L (leucine preferring) amino acid transporter. The purpose of this study was to evaluate in vivo uptake and single-dose toxicity of anti-2-[{sup 18}F]FACPC-1 in animals as well as the individual organ and whole-body dose in humans. Methods: A DU145 xenograft rodent model was used to measure anti-2-[{sup 18}F]FACPC-1 uptake at 15, 30 and 60 min post-injection. Animals were sacrificed and organs harvested to measure the percent injected activity per organ and to calculate residence time. Anti-2-[{sup 18}F]FACPC-1 toxicity was assessed using a single microdose (37-74 MBq/kg) in nonhuman primates. Their vital signs were monitored for 2 h post-injection for drug-related effects. Human biodistribution studies were collected by sequential whole-body PET/CT scans on six healthy volunteers (three male and three female) for 120 min following a single 247{+-}61 MBq bolus injection of anti-2-[{sup 18}F]FACPC-1. Estimates of radiation dose from anti-2-[{sup 18}F]FACPC-1 to the human body were calculated using recommendations of the MIRD committee and MIRDOSE 3.0 software. Results: High anti-2-[{sup 18}F]FACPC-1 residence time was observed in the pancreas of the rodent model compared to the human data. No abnormal treatment-related observations were made in the nonhuman primate toxicity studies. Human venous blood showed no metabolites of anti-2-[{sup 18}F]FACPC-1 in the first 60 min post-injection. All volunteers showed initially high uptake in the kidneys followed by a rapid washout phase. The estimated effective dose equivalent was 0.0196 mSv/MBq. Conclusion: Anti-2-[{sup 18}F]FACPC-1 showed low background uptake in the brain, thoracic and abdominal cavities of humans, suggesting a possible use for detecting

  8. Synthesis, spectroscopic characterization and in vitro antimicrobial, anticancer and antileishmanial activities as well interaction with Salmon sperm DNA of newly synthesized carboxylic acid derivative, 4-(4-methoxy-2-nitrophenylamino)-4-oxobutanoic acid

    Science.gov (United States)

    Sirajuddin, Muhammad; Ali, Saqib; McKee, Vickie; Ullah, Hameed

    2015-03-01

    This paper stresses on the synthesis, characterization of novel carboxylic acid derivative and its application in pharmaceutics. Carboxylic acid derivatives have a growing importance in medicine, particularly in oncology. A novel carboxylic acid, 4-(4-methoxy-2-nitrophenylamino)-4-oxobutanoic acid, was synthesized and characterized by elemental analysis, FT-IR, NMR (1H, and 13C), mass spectrometry and single crystal X-ray structural analysis. The structure of the title compound, C11H12N2O6, shows the molecules dimerised by short intramolecular Osbnd H⋯O hydrogen bonds. The compound was screened for in vitro antimicrobial, anticancer, and antileishmanial activities as well as interaction with SS-DNA. The compound was also checked for in vitro anticancer activity against BHK-21, H-157 and HCEC cell lines, and showed significant anticancer activity. The compound was almost non-toxic towards human corneal epithelial cells (HCEC) and did not show more than 7.4% antiproliferative activity when used at the 2.0 μg/mL end concentration. It was also tested for antileishmanial activity against the promastigote form of leishmania major and obtained attractive result. DNA interaction study exposes that the binding mode of the compound with SS-DNA is an intercalative as it results in hypochromism along with minor red shift. A new and efficient strategy to identify pharmacophores sites in carboxylic acid derivative for antibacterial/antifungal activity using Petra, Osiris and Molinspiration (POM) analyses was also carried out.

  9. Pancreatic ductal bicarbonate secretion: challenge of the acinar acid load

    Directory of Open Access Journals (Sweden)

    Peter eHegyi

    2011-07-01

    Full Text Available Acinar and ductal cells of the exocrine pancreas form a close functional unit. Although most studies contain data either on acinar or ductal cells, an increasing number of evidence highlights the importance of the pancreatic acinar-ductal functional unit. One of the best examples for this functional unit is the regulation of luminal pH by both cell types. Protons co-released during exocytosis from acini cause significant acidosis, whereas, bicarbonate secreted by ductal cells cause alkalization in the lumen. This suggests that the first and probably one of the most important role of bicarbonate secretion by pancreatic ductal cells is not only to neutralize the acid chyme entering into the duodenum from the stomach, but to neutralize acidic content secreted by acinar cells. To accomplish this role, it is more than likely that ductal cells have physiological sensing mechanisms which would allow them to regulate luminal pH. To date, four different classes of acid-sensing ion channels have been identified in the gastrointestinal tract (transient receptor potential ion channels, two-pore domain potassium channel, ionotropic purinoceptor and acid-sensing ion channel, however, none of these have been studied in pancreatic ductal cells. In this mini-review, we summarize our current knowledge of these channels and urge scientists to characterize ductal acid-sensing mechanisms and also to investigate the challenge of the acinar acid load on ductal cells.

  10. Determination of pKa and Hydration Constants for a Series of α-Keto-Carboxylic Acids Using Nuclear Magnetic Resonance Spectrometry.

    Science.gov (United States)

    Lopalco, Antonio; Douglas, Justin; Denora, Nunzio; Stella, Valentino J

    2016-02-01

    The determination of the acid-base dissociation constants, and thus the pKa values, of α-keto acids such as pyruvic acid is complex because of the existence of these acids in their hydrated and nonhydrated or oxo state. Equilibria involved in the hydration and dehydration of the α-keto group of pyruvic acid and three other α-keto acids, 3-methyl-2-oxobutanoic acid, 4-methyl-2-oxopentanoic acid, and 2-oxo-2-phenylacetic acid, were investigated by proton and carbon nuclear magnetic resonance spectrometry, at constant ionic strength, 0.15, and 25 °C. Dissociation constants for the oxo (pKa(oxo)) and hydrated (pKa(hyd)) acids of each compound were estimated from the change in the degree of hydration with changes in pH and directly from the changes in chemical shifts of various hydrogen and carbons nuclei with pH. α-Keto acids showed greater hydration in their acidic forms than their carboxylate forms. The degree of hydration was sensitive to steric and electronic/resonance factors. As expected, the oxo forms of the acids were stronger acids compared with their hydrated analogs, and their dissociation constants were also sensitive to steric and electronic factors.

  11. Synthesis and photophysical behavior of a novel zinc phthalocyanine containing a single carboxylic acid and three phenylthio substituents

    Energy Technology Data Exchange (ETDEWEB)

    Forteath, Shaun; Antunes, Edith; Chidawanyika, Wadzanai [Department of Chemistry, Rhodes University, Grahamstown, P.O. Box 94, 6139 Grahamstown, Eastern Cape (South Africa); Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za [Department of Chemistry, Rhodes University, Grahamstown, P.O. Box 94, 6139 Grahamstown, Eastern Cape (South Africa)

    2012-09-15

    Zinc 2, (3)-tri-(phenylthio)-2, (3)-carboxy phthalocyanine (ZnPc(COOH)(SPh){sub 3}), zinc 2, (3)-tetra-(phenylthio) phthalocyanine (ZnPc(SPh){sub 4}) and 2, (3)-tetra-(phenylthio) phthalocyanine (H{sub 2}Pc(SPh){sub 4}) were synthesized and their photophysical behavior were compared with those of a number of zinc phthalocyanine (ZnPc) derivatives. ZnPc(COOH)(SPh){sub 3} and ZnPc(SPh){sub 4} had similar fluorescence ({Phi}{sub F}=0.14) and triplet state ({Phi}{sub T}=0.65) quantum yields in dimethylsulfoxide, hence showing no effects of the replacement of one of the phenylthio groups with a carboxylic acid group. ZnPc(COOH)(SPh){sub 3} displayed a slightly shorter triplet lifetime ({tau}{sub T}=331 {mu}s) than ZnPc ({tau}{sub T}=350 {mu}s) in DMSO, but within the range of ZnPc derivatives. The triplet lifetime for ZnPc(COOH)(SPh){sub 3} is much longer than for the symmetrical derivative (ZnPc(SPh){sub 4}) with {tau}{sub T}=149 {mu}s in DMSO. - Graphical Abstract: Zinc 2, (3)-tri-(phenylthio)-2, (3)-carboxy phthalocyanine (ZnPc(COOH)(SPh){sub 3}) showed much higher triplet lifetime than the corresponding symmetrically substituted derivative. Highlights: Black-Right-Pointing-Pointer An unsymmetrically substituted zinc phthalocyanine is synthesized. Black-Right-Pointing-Pointer Unsymmetrical substitution results in larger triplet lifetimes. Black-Right-Pointing-Pointer Unsymmetrical substitution does not alter triplet or fluorescence quantum yields. Black-Right-Pointing-Pointer Monoexponential fluorescence lifetimes are obtained.

  12. Simultaneous Determination and Pharmacokinetics of Metolazone, Losartan and Losartan Carboxylic Acid in Rat Plasma by HPLC-ESI-MS-MS.

    Science.gov (United States)

    Dubey, Ramkumar; Ghosh, Manik; Sinha, Barij Nayan; Muthukrishnan, Venkateswari

    2015-10-01

    For the first time, we developed and validated a highly sensitive, selective and rapid HPLC-ESI-MS-MS method for simultaneous quantification of metolazone (MET), losartan (LOS) and its metabolite losartan carboxylic acid (LCA) in rat plasma. After solid-phase extraction, the analytes and internal standard (irbesartan) were extracted from 100 µL plasma sample on an Agilent Poroshell 120, EC-C18 (50 × 4.6 mm, i.d., 2.7 µm) column using 5 µL injection volume with a total run time of 3 min. Acidified methanol/water mixture was used as a mobile phase. The parent → product ion transitions for MET (m/z 366.0 → 258.9), LOS (m/z 423.2 → 207.0), LCA (m/z 437.0 → 235.1) and IS (m/z 429.2 → 207.0) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring and positive ion mode. The method was found to be linear in the range of 0.05-250 for MET, 2-3,000 for LOS and 4-3,500 ng/mL for LCA. The method was validated with respect to selectivity, linearity, accuracy, precision, recovery and stability according to accepted regulatory guidelines. The described method was successfully applied to preclinical pharmacokinetic studies of analytes after an oral administration of mixture of MET (1 mg/kg) and LOS (10 mg/kg) in rats.

  13. The Synthetic Elicitor 2-(5-Bromo-2-Hydroxy-Phenyl)-Thiazolidine-4-Carboxylic Acid Links Plant Immunity to Hormesis.

    Science.gov (United States)

    Rodriguez-Salus, Melinda; Bektas, Yasemin; Schroeder, Mercedes; Knoth, Colleen; Vu, Trang; Roberts, Philip; Kaloshian, Isgouhi; Eulgem, Thomas

    2016-01-01

    Synthetic elicitors are drug-like compounds that induce plant immune responses but are structurally distinct from natural defense elicitors. Using high-throughput screening, we previously identified 114 synthetic elicitors that activate the expression of a pathogen-responsive reporter gene in Arabidopsis (Arabidopsis thaliana). Here, we report on the characterization of one of these compounds, 2-(5-bromo-2-hydroxy-phenyl)-thiazolidine-4-carboxylic acid (BHTC). BHTC induces disease resistance of plants against bacterial, oomycete, and fungal pathogens and has a unique mode of action and structure. Surprisingly, we found that low doses of BHTC enhanced root growth in Arabidopsis, while high doses of this compound inhibited root growth, besides inducing defense. These effects are reminiscent of the hormetic response, which is characterized by low-dose stimulatory effects of a wide range of agents that are toxic or inhibitory at higher doses. Like its effects on defense, BHTC-induced hormesis in Arabidopsis roots is partially dependent on the WRKY70 transcription factor. Interestingly, BHTC-induced root hormesis is also affected in the auxin-response mutants axr1-3 and slr-1. By messenger RNA sequencing, we uncovered a dramatic difference between transcriptional profiles triggered by low and high doses of BHTC. Only high levels of BHTC induce typical defense-related transcriptional changes. Instead, low BHTC levels trigger a coordinated intercompartmental transcriptional response manifested in the suppression of photosynthesis- and respiration-related genes in the nucleus, chloroplasts, and mitochondria as well as the induction of development-related nuclear genes. Taken together, our functional characterization of BHTC links defense regulation to hormesis and provides a hypothetical transcriptional scenario for the induction of hormetic root growth.

  14. Influence of carboxylic acid type on microstructure and magnetic properties of polymeric complex sol-gel driven NiFe2O4

    Science.gov (United States)

    Hessien, M. M.; Mostafa, Nasser Y.; Abd-Elkader, Omar H.

    2016-01-01

    Citric, oxalic and tartaric acids were used for synthesis of NiFe2O4 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 NiFe2O4 with considerable amount of α-Fe2O3 at 400 °C. Increase in the annealing temperature caused reaction of α-Fe2O3 with iron-deficient ferrite phase. The amount of initially formed α-Fe2O3 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-Fe2O3. Maximum saturation magnetization (55 emu/g) was achieved using tartaric acid precursor annealed at 1100 °C.

  15. 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.

  16. Syntheses of Four Enantiomers of 2,3-Diendo- and 3-Endo-aminobicyclo[2.2.2]oct-5-ene-2-exo-carboxylic Acid and Their Saturated Analogues

    Directory of Open Access Journals (Sweden)

    Márta Palkó

    2013-12-01

    Full Text Available Ethyl 2,3-diendo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylate ((±-1 was resolved with O,O'-dibenzoyltartaric acid via diastereomeric salt formation. The efficient synthesis of the enantiomers of 2,3-diendo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid ((+-7 and (–-7, 3-endo-aminobicyclo[2.2.2]oct-5-ene-2-exo-carboxylic acid ((+-5 and (–-5, cis- and trans-3-aminobicyclo[2.2.2]octane-2-carboxylic acid ((+-6, (–-6, (+-8 and (–-8 was achieved via isomerization, hydrogenation and hydrolysis of the corresponding esters (–-1 and (+-1. The stereochemistry and relative configurations of the synthesized compounds were determined by NMR spectroscopy (based on the 3J(H,H coupling constants and X-ray crystallography.

  17. Synthesis, structures, electrochemical studies and antioxidant activity of 5-aryl-4-oxo-3,4,5,8-tetrahydropyrido[2,3-d]pyrimidine-7-carboxylic acids

    Science.gov (United States)

    Quiroga, Jairo; Romo, Pablo E.; Ortiz, Alejandro; Isaza, José Hipólito; Insuasty, Braulio; Abonia, Rodrigo; Nogueras, Manuel; Cobo, Justo

    2016-09-01

    The synthesis of 5-aryl-4-oxo-3,4,5,8-tetrahydropyrido[2,3-d]pyrimidine-7-carboxylic acids 3 from the reaction of 6-aminopyrimidines 1 with arylidene derivatives of pyruvic acid 2 under microwave and ultrasound irradiation is described. The orientation of cyclization process was determined by NMR measurements. The methodology provides advantages such as high yields and friendly to the environment without the use of solvents. The antioxidant properties, DPPH free radical scavenging, ORAC, and anodic potential oxidation of the new pyridopyrimidines were studied.

  18. A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

    Directory of Open Access Journals (Sweden)

    Christian Eidamshaus

    2011-07-01

    Full Text Available A practical approach to highly functionalized 4-hydroxypyridine derivatives with stereogenic side chains in the 2- and 6-positions is described. The presented two-step process utilizes a multicomponent reaction of alkoxyallenes, nitriles and carboxylic acids to provide β-methoxy-β-ketoenamides which are transformed into 4-hydroxypyridines in a subsequent cyclocondensation. The process shows broad substrate scope and leads to differentially substituted enantiopure pyridines in good to moderate yields. The preparation of diverse substituted lactic acid derived pyrid-4-yl nonaflates is described. Additional evidence for the postulated mechanism of the multicomponent reaction is presented.

  19. Isomers of various species of 1-hydroxy-2-pyridinone-6-carboxylic acid, their proton dissociation and complexes with Cr(III) and Zn(II)

    Science.gov (United States)

    Thipyapong, Khajadpai; Ruangpornvisuti, Vithaya

    2008-11-01

    Isomers of 1-hydroxy-2-pyridinone-6-carboxylic acid (6-carboxy-1,2-HOPO), their deprotonated species and complexes with chromium and zinc were theoretically investigated by density functional theory calculations. Free energy of activation, energetics, thermodynamic properties and equilibrium constants of interconversion reactions of their isomers were determined. Measured acid-dissociation constants of the 6-carboxy-1,2-HOPO obtained from potentiometric titration method were compared with the computed constants which were derived from the density functional theory method. Two isomers of each 6-carboxy-1,2-HOPO complexes with chromium and with zinc were found.

  20. 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.

  1. Synthesis of syn- and anti-1-amino-3-[18F]fluoromethyl-cyclobutane-1-carboxylic acid (FMACBC), potential PET ligands for tumor detection.

    Science.gov (United States)

    Martarello, Laurent; McConathy, Jonathan; Camp, Vernon M; Malveaux, Eugene J; Simpson, Nicholas E; Simpson, Chiab P; Olson, Jeffrey J; Bowers, Geoffrey D; Goodman, Mark M

    2002-05-23

    syn- and anti-1-amino-3-[18F]fluoromethyl-cyclobutane-1-carboxylic acid (FMACBC, 16 and 17), analogues of anti-1-amino-3-[18F]fluorocyclobutyl-1-carboxylic acid (FACBC), were prepared to evaluate the contributions of C-3 substitution and configuration on the uptake of these radiolabeled amino acids in a rodent model of brain tumors. Radiofluorinated targets [18F]16 and [18F]17 were prepared by no-carrier-added radiofluorination from their corresponding methanesulfonyl esters 12 and 13, respectively, with decay-corrected radiochemical yields of 30% for [18F]16 and 20% for [18F]17. In amino acid transport assays performed in vitro using 9L gliosarcoma cells, both [18F]16 and [18F]17 were substrates for L type amino acid transport, while [18F]17 but not [18F]16 was a substrate for A type transport. Biodistribution studies in normal Fischer rats with [18F]16 and [18F]17 showed high uptake of radioactivity (>2.0% dose/g) in the pancreas while other tissues studied, including liver, heart, lung, kidney, blood, muscle, and testis, showed relatively low uptake of radioactivity (FACBC, [18F]16 and [18F]17 are excellent candidates for imaging brain tumors.

  2. Gibberellic Acid, Synthetic Auxins, and Ethylene Differentially Modulate α-l-Arabinofuranosidase Activities in Antisense 1-Aminocyclopropane-1-Carboxylic Acid Synthase Tomato Pericarp Discs1

    Science.gov (United States)

    Sozzi, Gabriel O.; Greve, L. Carl; Prody, Gerry A.; Labavitch, John M.

    2002-01-01

    α-l-Arabinofuranosidases (α-Afs) are plant enzymes capable of releasing terminal arabinofuranosyl residues from cell wall matrix polymers, as well as from different glycoconjugates. Three different α-Af isoforms were distinguished by size exclusion chromatography of protein extracts from control tomatoes (Lycopersicon esculentum) and an ethylene synthesis-suppressed (ESS) line expressing an antisense 1-aminocyclopropane-1-carboxylic synthase transgene. α-Af I and II are active throughout fruit ontogeny. α-Af I is the first Zn-dependent cell wall enzyme isolated from tomato pericarp tissues, thus suggesting the involvement of zinc in fruit cell wall metabolism. This isoform is inhibited by 1,10-phenanthroline, but remains stable in the presence of NaCl and sucrose. α-Af II activity accounts for over 80% of the total α-Af activity in 10-d-old fruit, but activity drops during ripening. In contrast, α-Af III is ethylene dependent and specifically active during ripening. α-Af I released monosaccharide arabinose from KOH-soluble polysaccharides from tomato cell walls, whereas α-Af II and III acted on Na2CO3-soluble pectins. Different α-Af isoform responses to gibberellic acid, synthetic auxins, and ethylene were followed by using a novel ESS mature-green tomato pericarp disc system. α-Af I and II activity increased when gibberellic acid or 2,4-dichlorophenoxyacetic acid was applied, whereas ethylene treatment enhanced only α-Af III activity. Results suggest that tomato α-Afs are encoded by a gene family under differential hormonal controls, and probably have different in vivo functions. The ESS pericarp explant system allows comprehensive studies involving effects of physiological levels of different growth regulators on gene expression and enzyme activity with negligible wound-induced ethylene production. PMID:12114586

  3. Impact of phenazine-1-carboxylic acid upon iron speciation and microbial biomass in the rhizosphere of wheat

    Science.gov (United States)

    LeTourneau, M.; Marshall, M.; Grant, M.; Freeze, P.; Cliff, J. B.; Lai, B.; Strawn, D. G.; Thomashow, L. S.; Weller, D. M.; Harsh, J. B.

    2015-12-01

    Phenazine-1-carboxylic acid (PCA) is a redox-active antibiotic produced by diverse bacterial taxa, and has been shown to facilitate interactions between biofilms and iron (hydr)oxides in culture systems (Wang et al. 2011, J Bacteriol 192: 365). Because rhizobacterial biofilms are a major sink for plant-derived carbon and source for soil organic matter (SOM), and Fe (hydr)oxides have reactive surfaces that influence the stability of microbial biomass and SOM, PCA-producing rhizobacteria could influence soil carbon fluxes. Large populations of Pseudomonas fluorescens strains producing PCA in concentrations up to 1 μg/g root have been observed in the rhizosphere of non-irrigated wheat fields covering 1.56 million hectares of central Washington state. This is one of the highest concentrations ever reported for a natural antibiotic in a terrestrial ecosystem (Mavrodi et al. 2012, Appl Environ Microb 78: 804). Microscopic comparisons of PCA-producing (PCA+) and non-PCA-producing (PCA-) rhizobacterial colony morphologies, and comparisons of Fe extractions from rhizosphere soil inoculated with PCA+ and PCA- strains suggest that PCA promotes biofilm development as well as dramatic Fe transformations throughout the rhizosphere (unpublished data). In order to illustrate PCA-mediated interactions between biofilms and Fe (hydr)oxides in the rhizosphere, identify the specific Fe phases favored by PCA, and establish the ramifications for stability and distribution of microbial biomass and SOM, we have collected electron micrographs, X-ray fluorescence images, X-ray absorption near-edge spectra, and secondary-ion mass spectrometry images of wheat root sections inoculated with 15N-labelled PCA+ or PCA- rhizobacteria. These images and spectra allow us to assess the accumulation, turnover, and distribution of microbial biomass, the associations between Fe and other nutrients such as phosphorus, and the redox status and speciation of iron in the presence and absence of PCA. This

  4. Synthesis of some 1,8-dioxoacridine carboxylic acid derivatives and the determination of their ionization constants in ethanol-water mixtures

    Science.gov (United States)

    Saygılı, Rukiye; Ulus, Ramazan; Yeşildağ, İbrahim; Kübra İnal, E.; Kaya, Muharrem; Murat Kalfa, O.; Zeybek, Bülent

    2015-03-01

    Four novel compounds of 1,8-dioxoacridine carboxylic acid derivatives (4-(3,3,6,6-tetramethyl-1,8-dioxo-9-phenyl-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-cyanophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(2,4-dichlorophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid) were prepared by the reaction of the 4-substitute benzaldehyde (hydrogen, hydroxyl, cyano, and 2,4-dichloro), 4-aminobenzoic acid, and 5,5-dimethylcyclohexane-1,3-dione in the presence of p-dodecylbenzenesulfonic acid. They were characterized by using FT-IR, 1H-NMR, 13C-NMR, GC-MS spectroscopic techniques. The stoichiometric ionization constants of these compounds were determined in ethanol-water mixtures of 50%, 60% and 70% ethanol (v/v) by potentiometric titration method and the ionization constants were calculated with three different ways. The effects of solvent composition and substituent groups on ionization constants of 1,8-dioxoacridine carboxylic acids were also discussed.

  5. 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.

  6. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework.

    Science.gov (United States)

    Demir, Selvan; Brune, Nicholas K; Van Humbeck, Jeffrey F; Mason, Jarad A; Plakhova, Tatiana V; Wang, Shuao; Tian, Guoxin; Minasian, Stefan G; Tyliszczak, Tolek; Yaita, Tsuyoshi; Kobayashi, Tohru; Kalmykov, Stepan N; Shiwaku, Hideaki; Shuh, David K; Long, Jeffrey R

    2016-04-27

    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, Sr(2+), Fe(3+), Nd(3+), and Am(3+), 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

  7. 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

  8. Oxidation of N-Nitrosoalkylamines by human cytochrome P450 2A6: sequential oxidation to aldehydes and carboxylic acids and analysis of reaction steps.

    Science.gov (United States)

    Chowdhury, Goutam; Calcutt, M Wade; Guengerich, F Peter

    2010-03-12

    Cytochrome P450 (P450) 2A6 activates nitrosamines, including N,N-dimethylnitrosamine (DMN) and N,N-diethylnitrosamine (DEN), to alkyl diazohydroxides (which are DNA-alkylating agents) and also aldehydes (HCHO from DMN and CH(3)CHO from DEN). The N-dealkylation of DMN had a high intrinsic kinetic deuterium isotope effect ((D)k(app) approximately 10), which was highly expressed in a variety of competitive and non-competitive experiments. The (D)k(app) for DEN was approximately 3 and not expressed in non-competitive experiments. DMN and DEN were also oxidized to HCO(2)H and CH(3)CO(2)H, respectively. In neither case was a lag observed, which was unexpected considering the k(cat) and K(m) parameters measured for oxidation of DMN and DEN to the aldehydes and for oxidation of the aldehydes to the carboxylic acids. Spectral analysis did not indicate strong affinity of the aldehydes for P450 2A6, but pulse-chase experiments showed only limited exchange with added (unlabeled) aldehydes in the oxidations of DMN and DEN to carboxylic acids. Substoichiometric kinetic bursts were observed in the pre-steady-state oxidations of DMN and DEN to aldehydes. A minimal kinetic model was developed that was consistent with all of the observed phenomena and involves a conformational change of P450 2A6 following substrate binding, equilibrium of the P450-substrate complex with a non-productive form, and oxidation of the aldehydes to carboxylic acids in a process that avoids relaxation of the conformation following the first oxidation (i.e. of DMN or DEN to an aldehyde). PMID:20061389

  9. 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)

    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

  10. Heterocyclic-2-carboxylic Acid (3-Cyano-1,4-di-N-oxidequinoxalin-2-ylamide Derivatives as Hits for the Development of Neglected Disease Drugs

    Directory of Open Access Journals (Sweden)

    Antonio Monge

    2009-06-01

    Full Text Available Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis (TB. Besides TB, Chagas disease, affects approximately 20 million people. Quinoxalines display great activities against TB and Chagas. Forty new quinoxaline 1,4-di-N-oxide derivatives have been prepared and tested against M. tuberculosis and T. cruzi. Carboxylic acid quinoxaline 1,4-di-N-oxides (CAQDOs 5 and 17 showed MIC values on the same order as the reference antituberculosis drug, rifampicin. Meanwhile, CAQDOs 12 and 22 presented IC50 values in the same order as the anti-chagasic drug, nifurtimox.

  11. Asymmetric Ring-Opening of Cyclopropyl Ketones with Thiol, Alcohol, and Carboxylic Acid Nucleophiles Catalyzed by a Chiral N,N'-Dioxide-Scandium(III) Complex.

    Science.gov (United States)

    Xia, Yong; Lin, Lili; Chang, Fenzhen; Fu, Xuan; Liu, Xiaohua; Feng, Xiaoming

    2015-11-01

    A highly efficient asymmetric ring-opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N'-dioxide-scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99% yield and 95% ee. This is also the first example of one catalytic system working for the ring-opening reaction of donor-acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version. PMID:26398505

  12. Ligand recognition by E- and P-selectin : chemoenzymatic synthesis and inhibitory activity of bivalent sialyl Lewis x derivatives and sialyl Lewis x carboxylic acids

    OpenAIRE

    Wittmann, Valentin; Takayama, Shuichi; Gong, Ke Wei; Weitz-Schmidt, Gabriele; Wong, Chi-Huey

    1998-01-01

    Described is the preparation of five sLex dimers and five sLex carboxylic acids by coupling chemoenzymatically synthesized amino-substituted sialyl Lewis x (sLex) derivative 4 to homobifunctional cross-linkers 20-24 of varying chain length. 20-24 were obtained by alkylating low-molecular-weight oligoethylene glycols with tert-butyl bromoacetate and subsequent transformation of the di-tert-butyl esters into disuccinimide esters. The products were assayed for inhibition against binding of a sLe...

  13. Directing Group in Decarboxylative Cross-Coupling: Copper-Catalyzed Site-Selective C-N Bond Formation from Nonactivated Aliphatic Carboxylic Acids.

    Science.gov (United States)

    Liu, Zhao-Jing; Lu, Xi; Wang, Guan; Li, Lei; Jiang, Wei-Tao; Wang, Yu-Dong; Xiao, Bin; Fu, Yao

    2016-08-01

    Copper-catalyzed directed decarboxylative amination of nonactivated aliphatic carboxylic acids is described. This intramolecular C-N bond formation reaction provides efficient access to the synthesis of pyrrolidine and piperidine derivatives as well as the modification of complex natural products. Moreover, this reaction presents excellent site-selectivity in the C-N bond formation step through the use of directing group. Our work can be considered as a big step toward controllable radical decarboxylative carbon-heteroatom cross-coupling. PMID:27439145

  14. Insight into 2α-Chloro-2′(2′,6′)-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O

    OpenAIRE

    Lingling Fan; Xiaoyan Zhi; Zhiping Che; Hui Xu

    2015-01-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2′(2′,6′)-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5–31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction tempera...

  15. Electrochemical impedance and spectroscopy study of the EDC/NHS activation of the carboxyl groups on poly(ε-caprolactone)/poly(m-anthranilic acid) nanofibers

    OpenAIRE

    Guler, Z.; Sarac, A.S.

    2016-01-01

    Electrochemical impedance spectroscopy (EIS) and spectroscopy was applied to investigate the surface activation of carboxyl group (–COOH) containing nanofibers by the reaction of 1-ethyl-3-(dimethyl-aminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxyl succinimide (NHS) in different concentrations. Poly(!-caprolactone)/poly(m-anthranilic acid) (PCL/P3ANA) nanofibers were fabricated by electrospinning and were activated with 5/0.5, 0.5/5, 5/5 and 50/50 mM of EDC/NHS. The surface activation ...

  16. Silica-gel-supported Phosphorus Pentoxide: a Simple and Efficient Solid-supported Reagent for Esterification of Long-Chain Carboxylic Acids and Their Antimicrobial Screening

    Institute of Scientific and Technical Information of China (English)

    RAUF Abdul; GANGAL Saloni; SHARMA Shweta

    2008-01-01

    A silica-gel-supported heterogeneous phosphorus pentoxide reagent has been developed for the esterification of various long-chain carboxylic acids with aromatic alcohols. The reactions occurred under relatively mild conditions and afforded the desired products in good yields. All the compounds 3a-3x were screened for antibacterial and antifungal activity, which showed good activity against Gram positive and Gram negative bacteria and also good results against almost all fungal strains. The structures of the synthesized compounds were elucidated by IR, 1H NMR,13C NMR, mass spectroscopic techniques and elemental analysis.

  17. Synthesis of novel precursors of Pfitzinger reaction: A facile one-pot strategy to the synthesis of quinoline carboxylic acid derivatives of pyrazolo-carbazoles and azacarbazoles

    Indian Academy of Sciences (India)

    Ruchi Tyagi; Bhawani Singh; D Kishore

    2012-03-01

    Interaction of 5-indazolyldiazonium chloride 2 with 2-hydroxymethylidene cyclohexanone 5 and -benzyl-3-hydroxymethylidene-4-piperidone 6 under the conditions of Japp-Klingemann reaction, followed by Fischer-indolization of the resulting hydrazones, formed the 5,7,8,9-tetrahydropyrazolo[4,3-b]carbazol- 6(1)-one 9 and 9-benzyl-5,7,8,9-tetrahydropyrido[2',3':4,5]pyrrolo[2,3-f]indazol-6(1)-one 10, respectively. Pfitzinger reaction of 9 and 10 with isatin in alkali afforded the corresponding quinoline carboxylic acid derivatives 12 and 13, respectively.

  18. Three silver-based complexes constructed from organic carboxylic acid and 4,4‧-bipyridine-like ligands: Syntheses, structures and photocatalytic properties

    Science.gov (United States)

    Wang, Chong-chen; Jing, Huan-ping; Wang, Peng

    2014-09-01

    The reactions of AgNO3 with combinations of 4,4‧-bipyridine (bpy)/1,2-di(4-pyridyl)ethylene (dpe), and 5-aminophthalic acid (H2ap)/2,6-Naphthalenedicarboxylic acid (H2npdc)/4,4‧-stilbenedicarboxylic acid (H2sbdc) in aqueous alcohol/ammonia at room temperature produce crystals of [Ag4(bpy)4](ap)2·11H2O (1), [Ag2(bpy)2](npdc)·2H2O (2) and [Ag2(dpe)1.5(sbdc)0.5](sbdc)0.5·7H2O (3). All complexes 1, 2 and 3 consist of 1D infinite silver-ligand cationic chains, interspersed with organic carboxylate anions that provide charge compensation in the crystal structures. The lattice water molecules are situated among the framework of the crystal structure and show rich hydrogen-bonding interactions, which serve to orientate of the organic carboxylate anions in the crystal packing, while the presence of Ag⋯N and Ag⋯Ag contacts strengthens the frameworks. In addition, complexes 1-3 exhibit good photocatalytic activities for dye decolorization under UV light.

  19. (1H-1,3-Benzimidazole-5,6-dicarboxylic acid(5-carboxylato-1H-1,3-benzimidazole-6-carboxylic acidsilver(I monohydrate

    Directory of Open Access Journals (Sweden)

    Hong Zhai

    2009-11-01

    Full Text Available The title compound, [Ag(C9H5N2O4(C9H6N2O4]·H2O, contains one independent Ag atom, a neutral 1H-benzimidazole-5,6-dicarboxylic acid (bdcH, its monodeprotonated form, i.e. 5-carboxylato-1H-1,3-benzimidazole-6-carboxylic acid (bdc, and one solvent water molecule, the latter being disordered over three sites with site occupancy factors of 0.375 (× 2 and 0.25. In addition, the H atom on one carboxylic acid residue is disordered, being connected to each of the O atoms 50% of the time. The Ag atom is in a virtually linear geometry defined by two N atoms derived from the bdc and bdcH ligands. The three-dimensional supramolecular structure is stablized by extensive O—H...O and N—H...O hydrogen bonds. An intramolecular O—H...O hydrogen bond is also present.

  20. Design, Synthesis, EPR-Studies and Conformational Bias of Novel Spin-Labeled DCC-Analogues for the Highly Regioselective Labeling of Aliphatic and Aromatic Carboxylic Acids.

    Science.gov (United States)

    Gölz, Jan Philipp; NejatyJahromy, Yaser; Bauer, Mirko; Muhammad, Ashraf; Schnakenburg, Gregor; Grimme, Stefan; Schiemann, Olav; Menche, Dirk

    2016-07-01

    Novel types of spin-labeled N,N'-dicyclohexylcarbodiimides (DCC) are reported that bear a 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) residue on one side and different aromatic and aliphatic cyclohexyl analogues on the other side of the diimide core. These readily available novel reagents add efficiently to aliphatic and aromatic carboxylic acids, forming two possible spin-labeled amide derivatives with different radical distances of the resulting amide. The addition of aromatic DCC analogues proceeds with excellent selectivity, giving amides where the carboxylic acid is exclusively connected to the aromatic residue, while little or no selectivity was observed for the aliphatic congeners. The usefulness of these adducts in structural studies was demonstrated by EPR (electron paramagnetic resonance) measurements of biradical adducts of biphenyl-4,4'-dicarboxylic acids. These analyses also reveal high degrees of conformational bias for aromatic DCC derivatives, which further underlines the powerfulness of these novel reagents. This observation was further corroborated by quantum chemical calculations, giving a detailed understanding of the structural dynamics, while detailed information on the solid state structure of all novel reagents was obtained by X-ray structure analyses. PMID:27272435

  1. The chemistry of aminoguanidine derivatives - preparation, crystal structure, thermal properties, and molecular docking studies of aminoguanidinium salts of several carboxylic acids

    Science.gov (United States)

    Selvakumar, Rajendran; Geib, Steven J.; Muthu Sankar, Aathi; Premkumar, Thathan; Govindarajan, Subbaiah

    2015-11-01

    The reaction of aminoguanidine bicarbonate (Amg) with oxamic, oxalic, malonic and sulfoacetic acids yielded (AmgH)H2NOC-COO (1), OOC-CONHNHC(NH2)NH2 (2) (AmgH)HOOC-CH2-COO (3) and O3S-CH2-CONHNHC(NH2)NH2 (4), respectively. For the first time, we studied the salt-forming ability of aminoguanidine with several carboxylic acids, such as oxamic, oxalic, malonic and sulphoacetic acids. We also compared the structural and thermal properties of these salts. Oxamic and malonic acids form only mono-aminoguanidinium salts, whereas oxalic acid mainly forms di-aminoguanidinium oxalate. In addition, oxalic acid forms guanylhydrazido-oxalic acid which exists as zwitter ion. Unlike other acids, sulfoacetic acid readily forms only the zwitter ionic salts (2-guanylhydrazido-oxo-methanesulfonic acid) rather than the usual simple salt. This result may be a result of the highly acidic nature of the sulfonic group, which favors acid catalyzed condensation. More significantly, for the first time, the ability guanylhydrazido-oxalic acid (2) and 2-guanylhydrazido-oxo-methanesulfonic acid (4) to inhibit human butyrylcholinesterase (human BChE) receptor has been studied with a molecular docking approach. The binding of the compounds to human BChE was examined as it is crucial to understanding the biological significance of aminoguanidine derivatives. The compounds were identified and characterized by analytical, FT-IR spectroscopic and thermal studies. Furthermore, the structures of compounds 1, 2 and 4 were confirmed by single X-ray diffraction studies. Compounds 1 and 2 crystallized in a monoclinic crystal system with P21/c and Cc space groups, respectively, whereas compound 4 crystalized in an orthorhombic system with a Pbca space group. All the compounds (1-4) underwent endo- followed by exothermic decomposition in the temperature range from 130 to 600 °C to yield gaseous products.

  2. Short branched-chain C6 carboxylic acids result in increased growth, novel 'unnatural' fatty acids and increased membrane fluidity in a Listeria monocytogenes branched-chain fatty acid-deficient mutant.

    Science.gov (United States)

    Sen, Suranjana; Sirobhushanam, Sirisha; Hantak, Michael P; Lawrence, Peter; Brenna, J Thomas; Gatto, Craig; Wilkinson, Brian J

    2015-10-01

    Listeria monocytogenes is a psychrotolerant food borne pathogen, responsible for the high fatality disease listeriosis, and expensive food product recalls. Branched-chain fatty acids (BCFAs) of the membrane play a critical role in providing appropriate membrane fluidity and optimum membrane biophysics. The fatty acid composition of a BCFA-deficient mutant is characterized by high amounts of straight-chain fatty acids and even-numbered iso fatty acids, in contrast to the parent strain where odd-numbered anteiso fatty acids predominate. The presence of 2-methylbutyrate (C5) stimulated growth of the mutant at 37°C and restored growth at 10°C along with the content of odd-numbered anteiso fatty acids. The C6 branched-chain carboxylic acids 2-ethylbutyrate and 2-methylpentanoate also stimulated growth to a similar extent as 2-methylbutyrate. However, 3-methylpentanoate was ineffective in rescuing growth. 2-Ethylbutyrate and 2-methylpentanoate led to novel major fatty acids in the lipid profile of the membrane that were identified as 12-ethyltetradecanoic acid and 12-methylpentadecanoic acid respectively. Membrane anisotropy studies indicated that growth of strain MOR401 in the presence of these precursors increased its membrane fluidity to levels of the wild type. Cells supplemented with 2-methylpentanoate or 2-ethylbutyrate at 10°C shortened the chain length of novel fatty acids, thus showing homeoviscous adaptation. These experiments use the mutant as a tool to modulate the membrane fatty acid compositions through synthetic precursor supplementation, and show how existing enzymes in L. monocytogenes adapt to exhibit non-native activity yielding unique 'unnatural' fatty acid molecules, which nevertheless possess the correct biophysical properties for proper membrane function in the BCFA-deficient mutant. PMID:26225744

  3. Synthesis and properties of new luminescent acridinium-9-carboxylic acid derivatives and their application in luminescence immunoassays (LIA).

    Science.gov (United States)

    Kinkel, T; Lübbers, H; Schmidt, E; Molz, P; Skrzipczyk, H J

    1989-07-01

    Two new groups of chemiluminescent acridinium labels have been presented: (a) acridinium-9-thiocarboxylates, (b) acridinium-9-(N-sulphonyl)carboxamides. Both groups show higher light yields and faster emission kinetics compared with the known acridinium carboxylate. Owing to the poor storage stability of the thiocarboxylate tracers they are not suitable for commercial use. Acridinium-9-(N-sulphonyl)carboxamides allow a variation of the structure, their stability after conjugation to antibodies is in most cases clearly better than the stability of thiocarboxylate and carboxylate tracers. Light yields and emission kinetics are also superior and good immunoassays have been developed. Therefore, this new class of chemiluminescent labels seems to be suitable for use in commercial assays. PMID:2801207

  4. FORMULATION DEVELOPMENT AND EVALUATION OF ABACAVIR LOADED POLYMETHACRYLIC ACID NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    S.L. Dheivanai

    2012-03-01

    Full Text Available Nanoparticles render a promising drug delivery system of controlled and targeted drug release. These are specially designed to release the drug in the vicinity of target tissue. The aim of this present study was to develop and evaluate polymethacrylic acid nanoparticles containing nanoparticles abacavir in different drug to polymer ratio by nanoprecipitation method. SEM indicates that nanoparticles have a discrete spherical structure without aggregation. The average particle size was accurately found to be 120 ±9 - 403 ±3 nm. The particle size of the nanoparticles was gradually increased with increase in the proportion of polymethacrylic acid polymer. The drug containing nanoparticles was increasing on increasing polymer concentration up to a particular concentration ratio. No difference was observed in the extent of degradation of product during sixty days in which, nanoparticles were stored at various temperatures. FT-IR studies indicated that there were no chemical interaction between drug and polymer and stability of drug. The in-vitro release character from all the drug loaded batches was found to be zero order and rendered sustained release over a period of 24 h. The prepared formulations overcome and breakup the drawbacks and limitations of abacavir sustained release formulations and could possibility be advantageous in terms of increased bioavailability and efficacy of abacavir.

  5. Enaminones as Building Blocks in Heterocyclic Syntheses: Reinvestigating the Product Structures of Enaminones with Malononitrile. A Novel Route to 6-Substituted-3-Oxo-2,3-Dihydropyridazine-4-Carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Mohamed Hilmy Elnagdi

    2008-12-01

    Full Text Available The reported structures of reaction products of enaminones with malononitrile in ethanolic piperidine are revised. A novel route to 2,3-dihydropyridazine-4-carboxylic acids 4a-c via reactions of 2-cyano-5-(dimethylamino-5-arylpenta-2,4-dienamides 8a-c with nitrous acid or with benzenediazonium chloride is reported. Compounds 8a-c are converted to 1,2-dihydropyridine-3-carboxylic acid and 1,2-dihydropyridine-3-carbonitrile derivatives upon reflux in EtOH/ HCl and in AcOH.

  6. Enaminones as Building Blocks in Heterocyclic Syntheses: Reinvestigating the Product Structures of Enaminones with Malononitrile. A Novel Route to 6-Substituted-3-Oxo-2,3-Dihydropyridazine-4-Carboxylic Acids

    OpenAIRE

    Mohamed Hilmy Elnagdi; Amal Al-Enezi; Mervat Mohammed Abdelkhalik; Abdul-Aziz Alnajjar

    2008-01-01

    The reported structures of reaction products of enaminones with malononitrile in ethanolic piperidine are revised. A novel route to 2,3-dihydropyridazine-4-carboxylic acids 4a-c via reactions of 2-cyano-5-(dimethylamino)-5-arylpenta-2,4-dienamides 8a-c with nitrous acid or with benzenediazonium chloride is reported. Compounds 8a-c are converted to 1,2-dihydropyridine-3-carboxylic acid and 1,2-dihydropyridine-3-carbonitrile derivatives upon reflux in EtOH/ HCl and in AcOH.

  7. 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.

  8. 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. PMID:27106067

  9. INTRACELLULAR ANTIOXIDANT ACTIVITY OF A STREPTOMYCES SP. 8812 SECONDARY METABOLITE, 6,7-DIHYDROXY-3,4-DIHYDROISOQINO- LINE-3-CARBOXYLIC ACID, AND ITS SYNTHETIC DERIVATIVES.

    Science.gov (United States)

    Guśpiel, Adam; Ziemska, Joanna; Cześcik, Agnieszka; Kawecki, Robert; Solecka, Jolanta

    2016-01-01

    The aim of this study was to determine the antioxidant properties of 6,7-dihydroxy-3,4-dihydroiso- quinoline-3-carboxylic acid (1) and its derivatives in living cells against reactive forms of oxygen and nitrogen, i.e., hydrogen peroxide and nitric oxide. Four of tested compounds scavenged the reactive form of nitrogen more efficiently or similarly to Trolox (EC50 = 55.80 µM). Two compounds exhibited antioxidant activity against reactive oxygen species better than Trolox (EC50 = 51.88 µM). The most active derivative of 1 was the compound containing an iodine atom at position 8 (6,7-dihydroxy-8-iodo-3,4-dihydroisoquinoline-3-carboxylic acid). Our studies showed that some of the derivatives had the ability to cross the cell membrane and scavenge free radicals inside living cells. Thus, they are able to protect DNA and other cellular structures from the dam- aging effects of reactive oxygen and nitrogen species. In addition, some molecular descriptors of the tested compounds were determined with the use of ICM Pro (Molsoft L.L.C.). PMID:27476282

  10. 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.

  11. 10-iodo-11H-indolo[3,2-c]quinoline-6-carboxylic acids are selective inhibitors of DYRK1A.

    Science.gov (United States)

    Falke, Hannes; Chaikuad, Apirat; Becker, Anja; Loaëc, Nadège; Lozach, Olivier; Abu Jhaisha, Samira; Becker, Walter; Jones, Peter G; Preu, Lutz; Baumann, Knut; Knapp, Stefan; Meijer, Laurent; Kunick, Conrad

    2015-04-01

    The protein kinase DYRK1A has been suggested to act as one of the intracellular regulators contributing to neurological alterations found in individuals with Down syndrome. For an assessment of the role of DYRK1A, selective synthetic inhibitors are valuable pharmacological tools. However, the DYRK1A inhibitors described in the literature so far either are not sufficiently selective or have not been tested against closely related kinases from the DYRK and the CLK protein kinase families. The aim of this study was the identification of DYRK1A inhibitors exhibiting selectivity versus the structurally and functionally closely related DYRK and CLK isoforms. Structure modification of the screening hit 11H-indolo[3,2-c]quinoline-6-carboxylic acid revealed structure-activity relationships for kinase inhibition and enabled the design of 10-iodo-substituted derivatives as very potent DYRK1A inhibitors with considerable selectivity against CLKs. X-ray structure determination of three 11H-indolo[3,2-c]quinoline-6-carboxylic acids cocrystallized with DYRK1A confirmed the predicted binding mode within the ATP binding site. PMID:25730262

  12. Fluorescence sensing of phosdrin pesticide by the luminescent Eu(III)- and Tb(III)-bis(coumarin-3-carboxylic acid) probes

    Science.gov (United States)

    Hussein, Belal H. M.; Khairy, Gasser M.; Kamel, Rasha M.

    2016-04-01

    Luminescence quenching of the Eu(III)- and Tb(III)-bis (coumarin-3-carboxylic acid) (Ln(III)-(CCA)2) probes has been studied in the presence of organophosphorus or organochlorine pesticides; Phosdrin (P1), Malathion (P2), Profenofos (P3), Formothion (P4), Heptachlor (P5), and Endosulfan (P6). The luminescence intensity of lanthanide complex probes Ln(III)-(CCA)2 decreases as the concentration of the Phosdrin pesticide increases, while the other investigated pesticides have no significant influence on the lanthanide fluorescent intensities. It is observed that the quenching of Eu(III) and Tb(III)-coumarin-3-carboxylic acid by Phosdrin proceeds via static quenching processes according to Stern-Volmer plot. The binding constants (K) and the thermodynamic parameters of the interaction of Ln(III)-(CCA)2 with Phosdrin have been determined. A direct method for the determination of the Phosdrin in ethanol has been developed based on the luminescence changes of the Ln(III)-(CCA)2-phosdrin ternary complexes. The detection limits of P1 were 6.28 and 1.07 μM in case of Eu(III) and Tb(III)-complex, respectively. The influence of various interfering species on the detection of P1 has been investigated to assess the analytical applicability of the method. The new method was applied to determine the Phosdrin pesticide in different types of water samples.

  13. 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.

  14. Arginine of retinoic acid receptor beta which coordinates with the carboxyl group of retinoic acid functions independent of the amino acid residues responsible for retinoic acid receptor subtype ligand specificity.

    Science.gov (United States)

    Zhang, Zeng Ping; Hutcheson, Juliet M; Poynton, Helen C; Gabriel, Jerome L; Soprano, Kenneth J; Soprano, Dianne Robert

    2003-01-15

    The biological actions of retinoic acid (RA) are mediated by retinoic acid receptors (RARalpha, RARbeta, and RARgamma) and retinoid X receptors (RXRalpha, RXRbeta, and RXRgamma). Consistent with the X-ray crystal structures of RARalpha and RARgamma, site-directed mutagenesis studies have demonstrated the importance of a conserved Arg residue (alphaArg(276), betaArg(269), and gammaArg(278)) for coordination with the carboxyl group of RA. However, mutation of Arg(269) to Ala in RARbeta causes only a 3- to 6-fold increase in the K(d) for RA and EC(50) in RA-dependent transcriptional transactivation assays while the homologous mutation in either RARalpha or RARgamma causes a 110-fold and a 45-fold increase in EC(50) value, respectively. To further investigate the nature of this difference, we prepared mutant RARs to determine the effect of conversion of betaR269A to a mutant which mimics either RARalpha ligand selectivity (betaA225S/R269A) or RARgamma ligand selectivity (betaI263M/R269A/V338A). Our results demonstrate that in RARbeta mutants that acquire either RARalpha or RARgamma ligand specificity the Arg(269) position responsible for coordination with the carboxyl group of retinoids continued to function like that of RARbeta. Furthermore, three mutant receptors (betaA225S/R269A, betaA225S/F279, and alphaF286A) were found to have a greater than wild-type affinity for the RARalpha-selective ligand Am580. Finally, a homology-based computer model of the ligand binding domain (LBD) of RARbeta and the X-ray crystal structures of the LBD of both RARalpha and RARgamma are used to describe potential mechanisms responsible for the increased affinity of some mutants for Am580 and for the difference in the effect of mutation of Arg(269) in RARbeta compared to its homologous Arg in RARalpha and RARgamma.

  15. Cleavage of the Carboxyl-Terminus of LEACS2, a Tomato 1-Aminocycl opropane-1-Carboxylic Acid Synthase Isomer, by a 64-kDa Tomato Metalloprotease Produces a Truncated but Active Enzyme

    Institute of Scientific and Technical Information of China (English)

    Jian-Feng LI; Robert QI; Liang-Hu QU; Autar K Mattoo; Ning LI

    2005-01-01

    l-Aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) is the principal enzyme in phytohormone ethylene biosynthesis. Previous studies have shown that the hypervariable C-terminus of ACS is proteolytically processed in vivo. However, the protease responsible for this has not yet been identified. In the present study, we investigated the processing of the 55-kDa full-length tomato ACS (LeACS2) into 52-, 50- and 49-kDa truncated isoforms in ripening tomato (Lycopersicon esculentum Mill. cv.Cooperation 903) fruit using the sodium dodecyl sulfate-boiling method. Meanwhile, an LeACS2-processing protease was purified via multi-step column chromatography from tomato fruit. Subsequent biochemical analysis of the 64-kDa purified protease revealed that it is a metalloprotease active at multiple cleavage sites within the hypervariable C-terminus of LeACS2. N-terminal sequencing and matrix-assisted laser desorption/ionization time-of-flight analysis indicated that the LeACS2-processing metalloprotease cleaves at the C-terminal sites Lys438, Glu447, Lys448, Asn456, Ser460, Ser462, Lys463, and Leu474, but does not cleave the Nterminus of LeACS2. Four C-terminus-deleted (26-50 amino acids) LeACS2 fusion proteins were overproduced and subjected to proteolysis by this metalloprotease to identify the multiple cleavage sites located on the N-terminal side of the phosphorylation site Ser460. The results indisputably confirmed the presence of cleavage sites within the region between the α-helix domain (H14) and Ser460 for this metalloprotease.Furhermore, the resulting C-terminally truncated LeACS2 isoforms were active enzymatically. Because this protease could produce LeACS2 isoforms in vitro similar to those detected in vivo, it is proposed that this metalloprotease may be involved in the proteolysis of LeACS2 in vivo.

  16. Origin of the 900 cm{sup −1} broad double-hump OH vibrational feature of strongly hydrogen-bonded carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Van Hoozen, Brian L.; Petersen, Poul B. [Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 (United States)

    2015-03-14

    Medium and strong hydrogen bonds are common in biological systems. Here, they provide structural support and can act as proton transfer relays to drive electron and/or energy transfer. Infrared spectroscopy is a sensitive probe of molecular structure and hydrogen bond strength but strongly hydrogen-bonded structures often exhibit very broad and complex vibrational bands. As an example, strong hydrogen bonds between carboxylic acids and nitrogen-containing aromatic bases commonly display a 900 cm{sup −1} broad feature with a remarkable double-hump structure. Although previous studies have assigned this feature to the OH, the exact origin of the shape and width of this unusual feature is not well understood. In this study, we present ab initio calculations of the contributions of the OH stretch and bend vibrational modes to the vibrational spectrum of strongly hydrogen-bonded heterodimers of carboxylic acids and nitrogen-containing aromatic bases, taking the 7-azaindole—acetic acid and pyridine—acetic acid dimers as examples. Our calculations take into account coupling between the OH stretch and bend modes as well as how both of these modes are affected by lower frequency dimer stretch modes, which modulate the distance between the monomers. Our calculations reproduce the broadness and the double-hump structure of the OH vibrational feature. Where the spectral broadness is primarily caused by the dimer stretch modes strongly modulating the frequency of the OH stretch mode, the double-hump structure results from a Fermi resonance between the out of the plane OH bend and the OH stretch modes.

  17. Solid Lipid Nanoparticles Loaded with Retinoic Acid and Lauric Acid as an Alternative for Topical Treatment of Acne Vulgaris.

    Science.gov (United States)

    Silva, Elton Luiz; Carneiro, Guilherme; De Araújo, Lidiane Advíncula; Trindade, Mariana de Jesus Vaz; Yoshida, Maria Irene; Oréfice, Rodrigo Lambert; Farias, Luis de Macêdo; De Carvalho, Maria Auxiliadora Roque; Dos Santos, Simone Gonçalves; Goulart, Gisele Assis Castro; Alves, Ricardo José; Ferreira, Lucas Antônio Miranda

    2015-01-01

    Topical therapy is the first choice for the treatment of mild to moderate acne and all-trans retinoic acid is one of the most used drugs. The combination of retinoids and antimicrobials is an innovative approach for acne therapy. Recently, lauric acid, a saturated fatty acid, has shown strong antimicrobial activity against Propionibacterium acnes. However, topical application of retinoic acid is followed by high incidence of side-effects, including erythema and irritation. Solid lipid nanoparticles represent an alternative to overcome these side-effects. This work aims to develop solid lipid nanoparticles loaded with retinoic acid and lauric acid and evaluate their antibacterial activity. The influence of lipophilic stearylamine on the characteristics of solid lipid nanoparticles was investigated. Solid lipid nanoparticles were characterized for size, zeta potential, encapsulation efficiency, differential scanning calorimetry and X-ray diffraction. The in vitro inhibitory activity of retinoic acid-lauric acid-loaded solid lipid nanoparticles was evaluated against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis. High encapsulation efficiency was obtained at initial time (94 ± 7% and 100 ± 4% for retinoic acid and lauric acid, respectively) and it was demonstrated that lauric acid-loaded-solid lipid nanoparticles provided the incorporation of retinoic acid. However, the presence of stearylamine is necessary to ensure stability of encapsulation. Moreover, retinoic acid-lauric acid-loaded solid lipid nanoparticles showed growth inhibitory activity against Staphylococcus epidermidis, Propionibacterium acnes and Staphylococcus aureus, representing an interesting alternative for the topical therapy of acne vulgaris. PMID:26328443

  18. Generating monomeric 5-coordinated microperoxidase-11 using carboxylic acid functionalized silver nanoparticles: A surface-enhanced resonance Raman scattering analysis.

    Science.gov (United States)

    Kalaivani, Govindasamy; Sivanesan, Arumugam; Kannan, Ayyadurai; Sevvel, Ranganathan

    2016-10-01

    Microperoxidase-11 (MP-11), a heme undecapeptide obtained by proteolytic digestion of cytochrome c, resembles peroxidase enzyme when its heme center is 5-coordinated with a vacant sixth coordination site. However, MP-11 always tends to aggregate in both solution and on surface and eventually forms the 6-coordinated heme. Thus, the present study investigates the immobilization strategy of MP-11 on nanoparticle surface in order to generate monomeric 5-coordinated MP-11 and make them as an efficient biocatalyst. The powerful surface-enhanced resonance Raman scattering (SERRS) technique is being employed to attain the detailed structural information of the catalytic site i.e., the heme center. The localized surface plasmon resonance (LSPR) tuned and 6-mercaptohexanoic acid (MHA) functionalized silver nanoparticles (Ag@MHA NPs) are used as Raman signal amplifier. The outcome of the SERRS study unambiguously portrays the existence of monomeric 5-coordinated MP-11 on Ag@MHA NPs surface. Here, Ag@MHA NPs plays a dual role of providing a platform to create monomeric 5-coordinated MP-11 and to load large number of MP-11 due to its high surface to volume ratio. Further, the electrostatic interaction between Ag@MHA NPs and MP-11 leads to instantaneous SERRS signal enhancement with a Raman enhancement factor (EFSERS) of 2.36×10(6). Langmuir adsorption isotherm has been employed for the adsorption of MP-11 on Ag@MHA NPs surface, which provides the real surface coverage (ΓS(*)) and equilibrium constant (K) value of 1.54nm and 5×10(11)M(-1). Furthermore, the peroxidase activity of MP-11 has been demonstrated through electrocatalytic oxygen reduction reaction. PMID:27434160

  19. Structural and biochemical study on the inhibitory activity of derivatives of 5-nitro-furan-2-carboxylic acid for RNase H function of HIV-1 reverse transcriptase.

    Science.gov (United States)

    Yanagita, Hiroshi; Urano, Emiko; Matsumoto, Kishow; Ichikawa, Reiko; Takaesu, Yoshihisa; Ogata, Masakazu; Murakami, Tsutomu; Wu, Hongui; Chiba, Joe; Komano, Jun; Hoshino, Tyuji

    2011-01-15

    Rapid emergence of drug-resistant variants is one of the most serious problems in chemotherapy for HIV-1 infectious diseases. Inhibitors acting on a target not addressed by approved drugs are of great importance to suppress drug-resistant viruses. HIV-1 reverse transcriptase has two enzymatic functions, DNA polymerase and RNase H activities. The RNase H activity is an attractive target for a new class of antiviral drugs. On the basis of the hit chemicals found in our previous screening with 20,000 small molecular-weight compounds, we synthesized derivatives of 5-nitro-furan-2-carboxylic acid. Inhibition of RNase H enzymatic activity was measured in a biochemical assay with real-time monitoring of florescence emission from the digested RNA substrate. Several derivatives showed higher inhibitory activities that those of the hit chemicals. Modulation of the 5-nitro-furan-2-carboxylic moiety resulted in a drastic decrease in inhibitory potency. In contrast, many derivatives with modulation of other parts retained inhibitory activities to varying degrees. These findings suggest the binding mode of active derivatives, in which three oxygen atoms aligned in a straight form at the nitro-furan moiety are coordinated to two divalent metal ions located at RNase H reaction site. Hence, the nitro-furan-carboxylic moiety is one of the critical scaffolds for RNase H inhibition. Of note, the RNase H inhibitory potency of a derivative was improved by 18-fold compared with that of the original hit compound, and no significant cytotoxicity was observed for most of the derivatives showing inhibitory activity. Since there is still much room for modification of the compounds at the part opposite the nitro-furan moiety, further chemical conversion will lead to improvement of compound potency and specificity. PMID:21193314

  20. Dietary potential renal Acid load in venezuelan children.

    Science.gov (United States)

    López-Sayers, Mayerling; Bernal, Jennifer; López, Michelle

    2015-05-01

    Objetivo: Determinar y analizar la carga acida potencial renal de la dieta (Potential Renal Acid Load PRAL) y el patron de alimentacion de ninos entre 1 a 6 anos aparentemente sanos. Métodos: Se seleccionaron segun conveniencia a padres de 52 ninos asistentes a una consulta de ninos sanos. La calidad de la dieta y el patron de alimentacion se evaluo mediante un recordatorio de 24 horas y un cuestionario de frecuencia de alimentos. Se calculo la ingesta de macronutrientes y grupos de alimentos, como carnes, lacteos, frutas y verduras. La ingesta de nutrientes se comparo con las recomendaciones de energia y nutrientes. El PRAL se determino segun el metodo de Remer y Manz, para determinar la carga acida de la dieta. Se aplico estadistica descriptiva y correlaciones entre el PRAL, nutrientes y grupos de alimentos. Resultados: La ingesta de proteinas, de leche y de carnes fue elevada, mientras que la ingesta de rutas y hortalizas fue baja. El PRAL fue positivo en 92% de los ninos, se asocio con mayor ingesta de energia, proteinas, grasas, carne y lacteos. La ingesta de proteinas fue > 2,5 g/kg/ dia en 46,2% de los ninos. Los grupos de alimentos con mayor desequilibrio debido a exceso fueron la carne y los productos lacteos, mientras que por deficit fue el grupo de frutas y hortalizas. Conclusión: La dieta se caracteriza por una elevada carga de acido o PRAL, lo que aumenta el riesgo de acidosis sistemica y sus consecuencias metabolicas.

  1. 不同稀释剂中三辛胺相对于有机羧酸碱度的研究%Relative Basicity of Trioctylamine to Carboxylic Acid in Selected Organic Diluents

    Institute of Scientific and Technical Information of China (English)

    单欣昌; 秦炜; 戴猷元

    2005-01-01

    The relative basicity of trioctylamine (TOA), pKa,BS, in protic polar diluent (1-octanol), non-protic polar diluent [methyl iso-butyl ketone (MIBK)] and inert diluent (CCl4) were determined for 11 mono-carboxylic acids, and the dependence of pKa,BS on the nature of solute and diluent type was discussed. The results show that pKa,BS determined by half neutralization with the solute carboxylic acid is in the order of 1-octanol>MIBK>CCl4for a fixed TOA concentration, and it increases with increasing acidity and hydrophobicity of the carboxylic acid.Compared with two parameters of the solute extracted (acidity and hydrophobicity), pKa,BS is more sensitive to hydrophobicity of the acid. A mathematic equation representing relationship between the apparent extraction equilibrium (K11) and the system properties (pKa,BS and pKa) was proposed: lg K11 = 2pKa,BS-pKa. It is proved that the extraction equilibrium of mono-carboxylic acids can be predicted by the above equation with reasonable accuracy.

  2. Docetaxel-loaded polylactic acid-co-glycolic acid nanoparticles: formulation, physicochemical characterization and cytotoxicity studies.

    Science.gov (United States)

    Pradhan, Roshan; Poudel, Bijay Kumar; Ramasamy, Thiruganesh; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2013-08-01

    In the present study, we developed novel docetaxel (DTX)-loaded polylactic acid-co-glycolic acid (PLGA) nanoparticles (NPs) using the combination of sodium lauryl sulfate (SLS) and poloxamer 407, the anionic and non-ionic surfactants respectively for stabilization. The NPs were prepared by emulsification/solvent evaporation method. The combination of these surfactants at weight ratio of 1:0.5 was able to produce uniformly distributed small sized NPs and demonstrated the better stability of NP dispersion with high encapsulation efficiency (85.9 +/- 0.6%). The drug/polymer ratio and phase ratio were 2:10 and 1:10, respectively. The optimized formulation of DTX-loaded PLGA NPs had a particle size and polydispersity index of 104.2 +/- 1.5 nm and 0.152 +/- 0.006, respectively, which was further supported by TEM image. In vitro release study was carried out with dialysis membrane and showed 32% drug release in 192 h. When in vitro release data were fitted to Korsmeyer-Peppas model, the n value was 0.481, which suggested the drug was released by anomalous or non-Fickian diffusion. In addition, DTX-loaded PLGA NPs in 72 h, displayed approximately 75% cell viability reduction at 10 microg/ml DTX concentration, in MCF-7 cell lines, indicating sustained release from NPs. Therefore, our results demonstrated that incorporation of DTX into PLGA NPs could provide a novel effective nanocarrier for the treatment of cancer.

  3. 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

  4. Intermolecular cycloaddition of nonstabilized azomethine ylides generated from 1,3-thiazolidine-4-carboxylic acids: synthesis of 5,7a-dihydro-1H,3H-pyrrolo[1,2-c]thiazoles

    OpenAIRE

    Cardoso, Ana L.; Kaczor, Agnieszka; Silva, Artur M. S.; Fausto, Rui; Melo, Teresa M.V.D. Pinho e; Gonsalves, António M. D'A Rocha

    2006-01-01

    The 1,3-dipolar cycloaddition of dimethyl acetylenedicarboxylate with nonstabilized azomethine ylides, generated via the decarboxylative condensation of 1,3-thiazolidine-4-carboxylic acids with aldehydes, afforded 5,7a-dihydro-1H,3H-pyrrolo[1,2-c]thiazole derivatives. 2-Substituted-1,3-thiazolidine-4-carboxylic acids led to the stereoselective formation of 5,7a-dihydro-1H,3H-pyrrolo[1,2-c]thiazoles. Quantum-chemistry calculations were carried out allowing the rationalization of the observed s...

  5. Chelation-assisted Pd-catalysed ortho-selective oxidative C-H/C-H cross-coupling of aromatic carboxylic acids with arenes and intramolecular Friedel-Crafts acylation: one-pot formation of fluorenones.

    Science.gov (United States)

    Sun, Denan; Li, Bijin; Lan, Jingbo; Huang, Quan; You, Jingsong

    2016-03-01

    Pd-Catalysed ortho-selective oxidative C-H/C-H cross-coupling of aromatic carboxylic acids with arenes and subsequent intramolecular Friedel-Crafts acylation has been accomplished for the first time through a chelation-assisted C-H activation strategy. Starting from the readily available substrates, a variety of fluorenone derivatives are obtained in one pot. The direct use of naturally occurring carboxylic acid functionalities as directing groups avoids unnecessary steps for installation and removal of an extra directing group. PMID:26861768

  6. Determination of small halogenated carboxylic acid residues in drug substances by high performance liquid chromatography-diode array detection following derivatization with nitro-substituted phenylhydrazines.

    Science.gov (United States)

    Hou, Desheng; Fan, Jingjing; Han, Lingfei; Ruan, Xiaoling; Feng, Feng; Liu, Wenyuan; Zheng, Feng

    2016-03-18

    A method for the determination of small halogenated carboxylic acid (HCA) residues in drug substances is urgently needed because of the potential of HCAs for genotoxicity and carcinogenicity in humans. We have now developed a simple method, involving derivatization followed by high performance liquid chromatography-diode array detection (HPLC-DAD), for the determination of six likely residual HCAs (monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, 2-chloropropionic acid, 2-bromopropionic acid and 3-chloropropionic acid) in drug substances. Different nitro-substituted phenylhydrazines (NPHs) derivatization reagents were systematically compared and evaluated. 2-Nitrophenylhydrazine hydrochloride (2-NPH·HCl) was selected as the most suitable choice since its derivatives absorb strongly at 392 nm, a region of the spectrum where most drug substances and impurities absorb very weakly. During the derivatization process, the commonly used catalyst, pyridine, caused rapid dechlorination or chlorine substitution of α-halogenated derivatives. To avoid these unwanted side reactions, a reliable derivatization method that did not use pyridine was developed. Reaction with 2-NPH·HCl using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as coupling agent in acetonitrile-water (70:30) at room temperature for 2h gave complete reaction and avoided degradation products. The derivatives were analyzed, without any pretreatment, using gradient HPLC with detection in the near visible region. Organic acids commonly found in drug substances and other impurities did not interfere with the analysis. Good linearity (r>0.999) and low limits of quantitation (0.05-0.12 μg mL(-1)) were obtained. The mean recoveries were in the range of 80-115% with RSD <5.81% except for 3-CPA in ibuprofen which was 78.5%. The intra- and inter-day precisions were expressed as RSD <1.98% and <4.39%, respectively. Finally, the proposed method was successfully used for the residue

  7. Determination of small halogenated carboxylic acid residues in drug substances by high performance liquid chromatography-diode array detection following derivatization with nitro-substituted phenylhydrazines.

    Science.gov (United States)

    Hou, Desheng; Fan, Jingjing; Han, Lingfei; Ruan, Xiaoling; Feng, Feng; Liu, Wenyuan; Zheng, Feng

    2016-03-18

    A method for the determination of small halogenated carboxylic acid (HCA) residues in drug substances is urgently needed because of the potential of HCAs for genotoxicity and carcinogenicity in humans. We have now developed a simple method, involving derivatization followed by high performance liquid chromatography-diode array detection (HPLC-DAD), for the determination of six likely residual HCAs (monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, 2-chloropropionic acid, 2-bromopropionic acid and 3-chloropropionic acid) in drug substances. Different nitro-substituted phenylhydrazines (NPHs) derivatization reagents were systematically compared and evaluated. 2-Nitrophenylhydrazine hydrochloride (2-NPH·HCl) was selected as the most suitable choice since its derivatives absorb strongly at 392 nm, a region of the spectrum where most drug substances and impurities absorb very weakly. During the derivatization process, the commonly used catalyst, pyridine, caused rapid dechlorination or chlorine substitution of α-halogenated derivatives. To avoid these unwanted side reactions, a reliable derivatization method that did not use pyridine was developed. Reaction with 2-NPH·HCl using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as coupling agent in acetonitrile-water (70:30) at room temperature for 2h gave complete reaction and avoided degradation products. The derivatives were analyzed, without any pretreatment, using gradient HPLC with detection in the near visible region. Organic acids commonly found in drug substances and other impurities did not interfere with the analysis. Good linearity (r>0.999) and low limits of quantitation (0.05-0.12 μg mL(-1)) were obtained. The mean recoveries were in the range of 80-115% with RSD <5.81% except for 3-CPA in ibuprofen which was 78.5%. The intra- and inter-day precisions were expressed as RSD <1.98% and <4.39%, respectively. Finally, the proposed method was successfully used for the residue

  8. Critical acidity loads in France; Charges critiques d`acidite en France

    Energy Technology Data Exchange (ETDEWEB)

    Probst, A.; Party, J.P.; Fevrier, C. [Centre de Geochimie de la Surface (UPR 06251 du CNRS), 67 - Strasbourg (France); Dambrine, E. [Centre de Recherches Forestieres, INRA, 45 - Orleans (France); Thomas, A.L.; King, D. [Institut National de Recherches Agronomique (INRA), 45 - ORDON (France); Stussi, J.M. [Centre National de la Recherche Scientifique (CNRS), 54 - Vandoeuvre-les-Nancy (France)

    1997-12-31

    Based on results from several systematic forest and surface water monitoring programs, carried out in various parts of France as well as in Europe, acidity critical loads have been calculated for soils and surface waters; critical loads are presented for water and soils in crystalline mountainous regions such as Ardennes, Vosges and Massif Central; links with geochemistry, ecosystems and types of trees are discussed and perspectives are given for the calculation of acid and nitrogen critical loads on the whole France

  9. Preparation and characterization of standard sample of 1-suifonic acid cyclohexane carboxylic acid%1-磺酸基环己烷羧酸标样的制备与表征

    Institute of Scientific and Technical Information of China (English)

    贺玉平; 段正康; 马帅; 李立南; 李文娟

    2012-01-01

    1 -Sulfonic acid cyclohexane carboxylic acid was obtained via decolorying of active carbon, acidifying of inorganic acids and crystallizing-out from the 1-sulfonic acid cyclohexane carboxylic acid crude salt of content about 80% in the treatment of finally waste fluid during the production of capro-lactam from toluene. The preparation conditions were optimized. The results showed that the purity of compounds reached 99. 8% and its structures were confirmed by IR and 1HNMR and 13CNMR. It can be used as standard sample of liquid chromatography.%甲苯法生产己内酰胺最终废液处理得到的含量在80%左右的1-磺酸基环己烷羧酸粗盐,经活性炭吸附脱色,无机强酸酸化结晶析出制备标题化合物,研究了制备条件,产品纯度达99.8%,其结构经IR、1HNMR和13CNMR确认,可作为液相色谱分析的标样使用.

  10. 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.

  11. 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

    International Nuclear Information System (INIS)

    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

  12. Carboxyl group reactivity in actin

    International Nuclear Information System (INIS)

    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. Stereoselective synthesis and biological evaluation of syn-1-amino-3-[18F]fluorocyclobutyl-1-carboxylic acid as a potential positron emission tomography brain tumor imaging agent.

    Science.gov (United States)

    Yu, Weiping; Williams, Larry; Camp, Vernon M; Malveaux, Eugene; Olson, Jeffrey J; Goodman, Mark M

    2009-03-01

    Amino acid syn-1-amino-3-fluoro-cyclobutyl-1-carboxylic acid (syn-FACBC) 12, the isomer of anti-FACBC, has been selectively synthesized and [(18)F] radiofluorinated in 52% decay-corrected yield using no-carrier-added [(18)F]fluoride. The key step in the synthesis of the desired isomer involved stereoselective reduction using lithium alkylborohydride/zinc chloride, which improved the ratio of anti-alcohol to syn-alcohol from 17:83 to 97:3. syn-FACBC 12 entered rat 9L gliosarcoma cells primarily via L-type amino acid transport in vitro with high uptake of 16% injected dose per 5 x 10(5) cells. Biodistribution studies in rats with 9L gliosarcoma brain tumors demonstrated high tumor to brain ratio of 12:1 at 30 min post injection. In this model, amino acid syn-[(18)F]FACBC 12 is a promising metabolically based radiotracer for positron emission tomography brain tumor imaging.

  14. Diversity-oriented synthesis of medicinally important 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives and higher analogs.

    Science.gov (United States)

    Kotha, Sambasivarao; Deodhar, Deepak; Khedkar, Priti

    2014-12-01

    1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid (Tic) is a constrained analog of phenylalanine (Phe). The Tic unit has been identified as a core structural element present in several peptide-based drugs and forms an integral part of various biologically active compounds. This report covers the biological significance of the Tic core and provides a detailed account of various synthetic approaches available for the construction of Tic derivatives. Along with the traditional methods such as the Pictet-Spengler and Bischler-Nepieralski reactions, we cover various recent approaches such as enyne metathesis, [2 + 2 + 2] cycloaddition and the Diels-Alder reaction to generate Tic derivatives. In addition, syntheses of higher analogs of Tic are also discussed. PMID:25299735

  15. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    Directory of Open Access Journals (Sweden)

    K. Ramesh

    2013-01-01

    Full Text Available Polyethylene glycols (PEGs were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours. The catalytic activity was found to be in the increasing order PEG-300 > PEG-400 > PEG-600 > PEG-200. Mechanism of PEG-mediated reactions was explained by Menger-Portnoy's scheme as applied in micellar kinetics.

  16. 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.

  17. Aqua-(pyridine-3-carb-oxy-lic acid-κN)(pyridine-2,6-dicarboxyl-ato-κO,N,O)copper(II) monohydrate.

    Science.gov (United States)

    Chen, Ting Ting; Shang, Yan Fang; Xi, Xia; Zhang, Yue Hua; Wang, Nan Ping

    2011-06-01

    In the title Cu(II) complex, [Cu(C(7)H(3)NO(4))(C(6)H(5)NO(2))(H(2)O)]·H(2)O, the environment of the Cu(2+) ion is a distorted square pyramid with the axial site occupied by the O atom from the coordinated water mol-ecule and the square base formed by two O and two N atoms from the tridentate anion and the neutral monodentate pyridine-3-carboxylic acid ligand. O-H⋯O hydrogen bonds, as well as π-π inter-actions [centroid-centroid distance = 3.945 (3) Å] contribute to the stabilization of this structure. PMID:21754683

  18. Aqua(pyridine-3-carboxylic acid-κN(pyridine-2,6-dicarboxylato-κ3O2,N,O6copper(II monohydrate

    Directory of Open Access Journals (Sweden)

    Ting Ting Chen

    2011-06-01

    Full Text Available In the title CuII complex, [Cu(C7H3NO4(C6H5NO2(H2O]·H2O, the environment of the Cu2+ ion is a distorted square pyramid with the axial site occupied by the O atom from the coordinated water molecule and the square base formed by two O and two N atoms from the tridentate anion and the neutral monodentate pyridine-3-carboxylic acid ligand. O—H...O hydrogen bonds, as well as π–π interactions [centroid–centroid distance = 3.945 (3 Å] contribute to the stabilization of this structure.

  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

    2014-09-01

    Molecular dynamics and molecular mechanics methods have been used to investigate additive-polymer interfacial properties in single walled carbon nanotube - polyethylene and single walled carbon nanotube - polyacrylonitrile composites. Properties such as the interfacial shear stress and bonding energy are similar for the two composites. In contrast, functionalizing the single walled carbon nanotubes 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 single walled carbon nanotube wall.

  20. Molecular level computational studies of polyethylene and polyacrylonitrile composites containing single walled carbon nanotubes: effect of carboxylic acid functionalization on nanotube-polymer interfacial properties

    Directory of Open Access Journals (Sweden)

    Shayesteh eHaghighatpanah

    2014-09-01

    Full Text Available Molecular dynamics and molecular mechanics methods have been used to investigate additive-polymer interfacial properties in single walled carbon nanotube – polyethylene and single walled carbon nanotube – polyacrylonitrile composites. Properties such as the interfacial shear stress and bonding energy are similar for the two composites. In contrast, functionalizing the single walled carbon nanotubes 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 single walled carbon nanotube wall.

  1. 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.

  2. Effect of low-molecular-weight carboxylic acids and selected synthetic chelates on zinc uptake and translocation in two wheat genotypes with different zinc-efficiency

    Directory of Open Access Journals (Sweden)

    Sh. Haftbaradaran

    2013-10-01

    Full Text Available Zinc (Zn deficiency in human, which results from diets low in bioavailable zinc, could be eliminated by increasing readily plant-available Zn in soil. Root exudates and organic acids released during decomposition of soil organic matter can affect the availability of Zn. Thus, this hydroponic experiment was conducted to investigate the effect of some chelates on Zn uptake and translocation in two wheat genotypes with different zinc-efficiency. Two wheat genotypes (Triticum aestivum L. Back Cross Rowshan as zinc-efficient and Kavir as zinc-inefficient were exposed to two levels of zinc (10 and 100 µM and six different carboxylic acids (citric, tartaric, oxalic, salicylic, ethylenediamin tetraacetic acid and L-methionine. Results showed that uptake capability of free and complexed species of Zn were completely different. Zn2+ activity in nutrient solution had negative correlation with shoot dry weight and positive correlation with shoot zinc concentration in Kavir genotype, while complexed species had opposite results. Back Cross Rowshan genotype showed opposite results in comparison with Kavir genotype. The response of wheat genotypes to different organic acids varied. EDTA treatment caused the lowest shoot zinc concentration in Kavir genotype (18.8 mg/kg, while the Back Cross Rowshan genotype had highest concentration (99.5 mg/kg. Tartaric acid and citric acid caused the lowest root Zn concentration in the Kavir genotype (26.7 and 58.6 mg/kg, respectively, while the highest content was observed in the Back Cross Rowshan genotype (83.2 and 98.1 mg/kg, respectively. Catalase activity had inverse relationship with root Zn concentration in both genotypes. According to the results of this research, different responses of the wheat genotypes to organic acids are related to different mechanisms of zinc-efficiency in genotypes.

  3. Development of a Controlled Release of Salicylic Acid Loaded Stearic Acid-Oleic Acid Nanoparticles in Cream for Topical Delivery

    Directory of Open Access Journals (Sweden)

    J. O. Woo

    2014-01-01

    Full Text Available Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release.

  4. Predictions of the fluorine NMR chemical shifts of perfluorinated carboxylic acids, CnF(2n+1)COOH (n = 6-8).

    Science.gov (United States)

    Liu, Zizhong; Goddard, John D

    2009-12-17

    Perfluorinated carboxylic acids (PFCAs) are a class of persistent environmental pollutants. Commercially available PFCAs are mixtures of linear and branched isomers, possibly with impurities. Different isomers have different physical and chemical properties and toxicities. However, little is known about the properties and the finer details of the structures of the individual branched isomers. Full geometry optimizations for the linear n-alkane (C(6)-C(27)) PFCAs indicated that all have helical structures. The helical angle increases slightly with increasing chain length, from 16.3 degrees in C(6)F(13)COOH to 17.0 degrees in C(27)F(55)COOH. This study predicts (19)F NMR parameters for 69 linear and branched isomers of the perfluoro carboxylic acids C(6)F(13)COOH, C(7)F(15)COOH, and C(8)F(17)COOH. B3LYP-GIAO/6-31++G(d,p)//B3LYP/6-31G(d,p) was used for the NMR calculations with analysis of the chemical shifts by the natural bond orbital method. The predictions of the (19)F chemical shifts revealed the differences among the CF(3), CF(2), and CF groups. In general, the absolute values for the chemical shifts for the CF(3) group are smaller than 90 ppm, for the CF larger than 160 ppm, and for the CF(2) between 110 and 130 ppm. The chemical shifts of the branched isomers are smaller in magnitude than the linear ones. The decrease is correlated with the steric hindrance of the CF(3) groups, the more hindered the CF(3), the greater the decrease in the (19)F chemical shifts. The predicted (19)F chemical shifts are similar to those for analogous perfluoro compounds with other terminal functional groups such as -SO(3)H or -SO(3)NH(2)CH(2)CH(3).

  5. The Influence of Co-Suppressing Tomato 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Ⅰ on the Expression of Fruit Ripening-Related and Pathogenesis-Related Protein Genes

    Institute of Scientific and Technical Information of China (English)

    HU Zong-li; CHEN Xu-qing; CHEN Guo-ping; L(U) Li-juan; Grierson Donald

    2007-01-01

    The purpose of this study is to explore the influence of co-suppressing tomato ACC oxidase I on the expression of fruit ripening-related and pathogenesis-related protein genes, and on the biosynthesis of endogenous ethylene and storage ability of fruits. Specific fragments of several fruit ripening-related and pathogenesis-related protein genes from tomato (Lycopersicon esculentum) were cloned, such as the 1-aminocyclopropane-1-carboxylic acid oxidase 1 gene (LeACO1), 1-aminocyclopropane-1-carboxylic acid oxidase 3 gene (LeAC03), EIN3-binding F-box 1 gene (LeEBF1), pathogenesisrelated protein 1 gene (LePR1), pathogenesis-related protein 5 gene (LePR5), and pathogenesis-related protein osmotin precursor gene (LeNP24) by PCR or RT-PCR. Then these specific DNA fragments were used as probes to hybridize with the total RNAs extracted from the wild type tomato Ailsa Craig (AC++) and the LeACO1 co-suppression tomatoes (V1187 and T4B), respectively. At the same time, ethylene production measurement and storage experiment of tomato fruits were carried out. The hybridization results indicated that the expression of fruit ripening-related genes such as LeACO3 and LeEBF1, and pathogenesis-related protein genes such as LePR1, LePR5, and LeNP24, were reduced sharply, and the ethylene production in the fruits, wounded leaves decreased and the storage time of ripening fruits was prolonged, when the expression of LeACO1 gene in the transgenic tomato was suppressed. In the co-suppression tomatoes, the expression of fruit ripening-related and pathogenesis-related protein genes were restrained at different degrees, the biosynthesis of endogenous ethylene decreased and the storage ability of tomato fruits increased.

  6. 2-Amino-4-methylpyrimidine: A simple supramolecular scaffold for carboxylic acid complexes both in solid and solution states

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Mahapatra, Ajit, E-mail: mahapatra574@gmail.co [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Sahoo, Prithidipa; Goswami, Shyamaprosad [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Fun, Hoong-Kun [X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2011-01-15

    Studies concentrating on hydrogen bonding interactions between 2-amino-4-methylpyrimidine (AMPY) with selected dicarboxylic acids have been investigated in the solid state. Two pyrimidinium-dicarboxylate organic salts with stoichiometry 1:1 [AMPY: maleic acid] and 2:1 [AMPY:D(+)-malic acid] have been prepared and characterized by X-ray crystallographic analysis. Maleic and D(+)-malic acids were found to exhibit unique supramolecular polymeric structures with AMPY involving proton transfer to the specific ring nitrogen of AMPY. As an extension, AMPY has been used to build a receptor structure 1. Receptor 1 shows binding of dicarboxylic acids in CH{sub 3}CN and represents a marginal selectivity with D(+)-malic acid. Binding interactions were investigated by UV-vis and fluorescence studies.

  7. Electrical properties of SAM-modified ITO surface using aromatic small molecules with double bond carboxylic acid groups for OLED applications

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • We report that the performance of OLED consist of aromatic small molecules with double bond carboxylic acid groups on ITO surface. • The OLED devices were tested in terms of electrical and optical characteristics. • The I–V results show that OLEDs with SAM-modified ITO surface have lower turn on voltages than OLED configurations without SAMs. - Abstract: 5-[(3-Methylphenyl)(phenyl)amino]isophthalic acid (5-MePIFA) and 5-(diphenyl)amino]isophthalic acid (5-DPIFA) organic molecules were synthesized to form self-assembled monolayer on indium tin oxide (ITO) anode to enhance hole transport from ITO to organic hole transport layers such as TPD. The modified surface was characterized by scanning tunneling microscopy (STM). The change in the surface potential was measured by Kelvin probe force microscopy (KPFM). Our Kelvin probe force microscopy (KPFM) measurements showed that the surface potentials increased more than 100 mV with reference to bare indium tin-oxide. The results show that the threshold voltage on OLEDs with modified ITO is lowered significantly compared to OLEDs with unmodified ITO. The hole mobility of TPD has been estimated using space–charge-limited current measurements (SCLC)

  8. Oxidative Stress Induced by Pt(IV) Pro-drugs Based on the Cisplatin Scaffold and Indole Carboxylic Acids in Axial Position

    Science.gov (United States)

    Tolan, Dina; Gandin, Valentina; Morrison, Liam; El-Nahas, Ahmed; Marzano, Cristina; Montagner, Diego; Erxleben, Andrea

    2016-07-01

    The use of Pt(IV) complexes as pro-drugs that are activated by intracellular reduction is a widely investigated approach to overcome the limitations of Pt(II) anticancer agents. A series of ten mono- and bis-carboxylated Pt(IV) complexes with axial indole-3-acetic acid (IAA) and indole-3-propionic acid (IPA) ligands were synthesized and characterized by elemental analysis, ESI-MS, FT-IR, 1H and 195Pt NMR spectroscopy. Cellular uptake, DNA platination and cytotoxicity against a panel of human tumor cell lines were evaluated. All the complexes are able to overcome cisplatin-resistance and the most potent complex, cis,cis,trans-[Pt(NH3)2Cl2(IPA)(OH)] was on average three times more active than cisplatin. Mechanistic studies revealed that the trend in cytotoxicity of the Pt(IV) complexes is primarily consistent with their ability to accumulate into cancer cells and to increase intracellular basal reactive oxygen species levels, which in turn results in the loss of mitochondrial membrane potential and apoptosis induction. The role of the indole acid ligand as a redox modulator is discussed.

  9. Novel 2-oxoimidazolidine-4-carboxylic acid derivatives as Hepatitis C virus NS3-4A serine protease inhibitors: synthesis, activity, and X-ray crystal structure of an enzyme inhibitor complex

    Energy Technology Data Exchange (ETDEWEB)

    Arasappan, Ashok; Njoroge, F. George; Parekh, Tejal N.; Yang, Xiaozheng; Pichardo, John; Butkiewicz, Nancy; Prongay, Andrew; Yao, Nanhua; Girijavallabhan, Viyyoor (SPRI)

    2008-06-30

    Synthesis and HCV NS3 serine protease inhibitory activity of some novel 2-oxoimidazolidine-4-carboxylic acid derivatives are reported. Inhibitors derived from this new P2 core exhibited activity in the low {micro}M range. X-ray structure of an inhibitor, 15c bound to the protease is presented.

  10. Supported -pyrrolidine-2-carboxylic acid-4-hydrogen sulphate on silica gel as an economical and efficient catalyst for the one-pot preparation of -acetamido ketones via a four-component condensation reaction

    Indian Academy of Sciences (India)

    Arash Ghorbani-Choghamarani; Parisa Zamani

    2014-01-01

    An efficient, one-pot, four-component condensation of aldehydes, acetophenone (or propiophenone), acetyl chloride and acetonitrile in the presence of catalytic amounts of -pyrrolidine-2-carboxylic acid-4-hydrogen sulphate (supported on silica gel), a green and non-toxic catalyst, is described for the preparation of -acetamido ketones in good to excellent yields.

  11. Preparation and drug-loading properties of Fe{sub 3}O{sub 4}/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wensheng [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China); Shen, Yuhua, E-mail: s_yuhua@163.com [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Xie, Anjian [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Zhang, Weiqiang [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China)

    2013-11-15

    Fe{sub 3}O{sub 4}/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe{sub 3}O{sub 4} nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50–120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe{sub 3}O{sub 4} nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

  12. Solubilization of amphiphilic carboxylic acids in nonionic micelles: determination of partition coefficients from pKa measurements and NMR experiments.

    Science.gov (United States)

    Dupont-Leclercq, Laurence; Giroux, Sébastien; Henry, Bernard; Rubini, Patrice

    2007-10-01

    The solubilization of octylamidotartaric acid (C8T) and octanoic acid (C8C) in Triton X-100 and Brij 58 nonionic micelles has been studied by pHmetric and 1H NMR self-diffusion experiments. As both C8C and C8T exhibit acid-base properties, a distinction between the partition of the neutral acidic form, in terms of the partition coefficient KPH, and the partition of the charged basic form, in terms of the partition coefficient KP-, has been made. The acidity constants, Ka, of C8T and C8C in the presence of micelles have been evaluated from pHmetric experiments. For both solutes, an increase in the pKa is observed in micellar media due to the difference in the partition of acidic and basic forms of the solutes. A model has been developed to determine KPH and KP- from the pKa shifts observed. The values obtained by this pKa shift modeling method and those from self-diffusion coefficient measurements are in good agreement. The acidic form of C8C is incorporated to a larger extent into the Brij 58 micelles than the acidic form of C8T, whereas the opposite trend is observed for the basic forms. Both the acidic and basic forms of C8T are more easily incorporated into Brij 58 micelles than into Triton X-100 micelles. The influence of the structure of the polar head on the solubilization properties is demonstrated. Moreover, evidence for the localization of the solutes in the micelles is obtained from the comparison of the partition coefficients and from 1H NMR data. PMID:17850105

  13. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV) Halides, Organotin (IV) Halides and Thicyanates*

    OpenAIRE

    R.C. Aggarwal; D.S.S. Vara Prasada Rao

    1981-01-01

    Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS)/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH), nicotinic acid hydrazide (NH) or isonicotinic acide hydrazide (INH), x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV a...

  14. Synthesis of 6-sulfamoyl-4-oxoquinoline-3-carboxylic acid derivatives as integrase antagonists with anti-HIV activity

    Institute of Scientific and Technical Information of China (English)

    Zai Gang Luo; Cheng Chu Zeng; Lei Fu Yang; Hong Qiu He; Cun Xin Wang; Li Ming Hu

    2009-01-01

    A series of novel 6-sulfamoyl-4-oxoquinoline-3-earboxylic acids derivatives have been synthesized and screened for HIV integrase inhibition activity. Their structures were confirmed by ESI-MS, 1H NMR and 13C NMR.

  15. 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.

  16. Antifungal activities of three different Lactobacillus species and their production of antifungal carboxylic acids in wheat sourdough.

    Science.gov (United States)

    Axel, Claudia; Brosnan, Brid; Zannini, Emanuele; Peyer, Lorenzo C; Furey, Ambrose; Coffey, Aidan; Arendt, Elke K

    2016-02-01

    This study was undertaken to assess the antifungal performance of three different Lactobacillus species.Experiments were conducted in vitro and in situ to extend the shelf life of wheat bread. Standard sourdough analyses were performed characterising acidity and carbohydrate levels. Overall, the strains showed good inhibition in vitro against the indicator mould Fusarium culmorum TMW4.2043. Sourdough bread fermented with Lactobacillus amylovorus DSM19280 performed best in the in situ shelf life experiment. An average shelf life extension of six more mould-free days was reached when compared to the non-acidified control bread. A range of antifungal-active acids like 3-phenyllactic acid, 4-hydroxyphenyllactic acid and 2-hydroxyisocaproic acid in quantities between 0.1 and 360 mg/kg were present in the freeze-dried sourdoughs. Their concentration differed greatly amongst the species.However, a higher concentration of these compounds could not completely justify the growth inhibition of environmental moulds. In particular, although Lb. reuteri R29 produced the highest total concentration of these active compounds in the sourdough, its addition to bread did not result in a longest shelf life. Nevertheless, when the artificial compounds were spiked into a chemically acidified dough, it succeeded in a longer shelf life (+25 %) than achieved only by acidifying the dough. This provides evidence of their contribution to the antifungal activity and their synergy in concentration levels far below their single minimal inhibition concentrations under acidic conditions.

  17. Antifungal activities of three different Lactobacillus species and their production of antifungal carboxylic acids in wheat sourdough.

    Science.gov (United States)

    Axel, Claudia; Brosnan, Brid; Zannini, Emanuele; Peyer, Lorenzo C; Furey, Ambrose; Coffey, Aidan; Arendt, Elke K

    2016-02-01

    This study was undertaken to assess the antifungal performance of three different Lactobacillus species.Experiments were conducted in vitro and in situ to extend the shelf life of wheat bread. Standard sourdough analyses were performed characterising acidity and carbohydrate levels. Overall, the strains showed good inhibition in vitro against the indicator mould Fusarium culmorum TMW4.2043. Sourdough bread fermented with Lactobacillus amylovorus DSM19280 performed best in the in situ shelf life experiment. An average shelf life extension of six more mould-free days was reached when compared to the non-acidified control bread. A range of antifungal-active acids like 3-phenyllactic acid, 4-hydroxyphenyllactic acid and 2-hydroxyisocaproic acid in quantities between 0.1 and 360 mg/kg were present in the freeze-dried sourdoughs. Their concentration differed greatly amongst the species.However, a higher concentration of these compounds could not completely justify the growth inhibition of environmental moulds. In particular, although Lb. reuteri R29 produced the highest total concentration of these active compounds in the sourdough, its addition to bread did not result in a longest shelf life. Nevertheless, when the artificial compounds were spiked into a chemically acidified dough, it succeeded in a longer shelf life (+25 %) than achieved only by acidifying the dough. This provides evidence of their contribution to the antifungal activity and their synergy in concentration levels far below their single minimal inhibition concentrations under acidic conditions. PMID:26481620

  18. The role of dietary acid load and mild metabolic acidosis in insulin resistance in humans.

    Science.gov (United States)

    Williams, Rebecca S; Kozan, Pinar; Samocha-Bonet, Dorit

    2016-05-01

    Type 2 diabetes is increasingly being recognised as a global health crisis (World Health Organisation). Insulin resistance is closely associated with obesity and precedes the development of type 2 diabetes. However, there is now increasing evidence to suggest that diet itself may independently be associated with type 2 diabetes risk. A diet with a high acid load (or high potential renal net acid load, PRAL) can result in a decrease in pH towards the lower end of the normal physiological range, which may in turn lead to the development of insulin resistance. Conversely, reducing dietary acid load (the so called 'alkaline diet') may be protective and prevent the onset of type 2 diabetes. Here, we explore the influence of dietary acid load on the development of mild metabolic acidosis and induction of insulin resistance. Whilst large prospective cohort studies link high dietary acid load or low serum bicarbonate with the development of type 2 diabetes, the effect of a diet with a low acid (or high alkaline) load remains unclear. Further interventional studies are required to investigate the influence of dietary composition on the body's acid/base balance, insulin resistance and incidence of type 2 diabetes. PMID:26363101

  19. Project 2: testing the current critical load maps of acidity for coniferous and deciduous forests.

    OpenAIRE

    Hornung, M.; Creamer, R.; Reynolds, B; Bell, S.; Langan, S.; Kennedy, F; Bradley, I.

    1999-01-01

    Objective: to examine the relationship between mapped exceedance of critical loads of acidity for woodlands, the Ca:A1 ratio of soil solution and forest status as measured by canopy condition and foliar chemistry

  20. Electrochemical impedance and spectroscopy study of the EDC/NHS activation of the carboxyl groups on poly(ε-caprolactone/poly(m-anthranilic acid nanofibers

    Directory of Open Access Journals (Sweden)

    Z. Guler

    2016-02-01

    Full Text Available Electrochemical impedance spectroscopy (EIS and spectroscopy was applied to investigate the surface activation of carboxyl group (–COOH containing nanofibers by the reaction of 1-ethyl-3-(dimethyl-aminopropyl carbodiimide hydrochloride (EDC/N-hydroxyl succinimide (NHS in different concentrations. Poly(!-caprolactone/poly(m-anthranilic acid (PCL/P3ANA nanofibers were fabricated by electrospinning and were activated with 5/0.5, 0.5/5, 5/5 and 50/50 mM of EDC/NHS. The surface activation was investigated by Attenuated Total Reflectance Fourier transform infrared spectroscopy (FTIR-ATR and activation yield was estimated. Albumin was immobilized after surface activation and the amount of covalently immobilized protein was determined by bicinchoninic acid (BCA assay. Morphology and composition of albumin immobilized nanofibers were characterized by Scanning Electron Microscopy/Energy-Dispersive X-ray Spectroscopy (SEM/EDX and Atomic force microscope (AFM. EIS measurements indicated that nanofibers become resistant after albumin immobilization. The obtained data revealed that the highest amount of albumin bound to nanofibers activated with 50/50 mM of EDC/NHS which was found to be the optimum concentration for the activation of PCL/P3ANA nanofibers.

  1. Insight into 2α-Chloro-2‧(2‧,6‧)-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O

    Science.gov (United States)

    Fan, Lingling; Zhi, Xiaoyan; Che, Zhiping; Xu, Hui

    2015-11-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2‧(2‧,6‧)-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5-31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction temperature were the important factors for C-ring aromatization, and AlCl3 could be substituted for BF3·Et2O as a lewis acid for C-ring aromatization. Halogenation of E-ring of 2β-chloropodophyllotoxins with NCS or NBS also led to the same C-ring aromatization compounds. Especially compounds 5c, 6g and 7b exhibited insecticidal activity equal to that of toosendanin.

  2. Insight into 2α-Chloro-2'(2',6')-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O.

    Science.gov (United States)

    Fan, Lingling; Zhi, Xiaoyan; Che, Zhiping; Xu, Hui

    2015-01-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2'(2',6')-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5-31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction temperature were the important factors for C-ring aromatization, and AlCl3 could be substituted for BF3·Et2O as a lewis acid for C-ring aromatization. Halogenation of E-ring of 2β-chloropodophyllotoxins with NCS or NBS also led to the same C-ring aromatization compounds. Especially compounds 5c, 6g and 7b exhibited insecticidal activity equal to that of toosendanin. PMID:26573374

  3. Synthesis, crystal structures, molecular docking, and in vitro biological activities evaluation of transition metal complexes with 4-(3,4-dichlorophenyl) piperazine-1-carboxylic acid

    Science.gov (United States)

    Chen, Zhi-Jian; Chen, Ya-Na; Xu, Chun-Na; Zhao, Shan-Shan; Cao, Qi-Yue; Qian, Shao-Song; Qin, Jie; Zhu, Hai-Liang

    2016-08-01

    Three novel mononuclear complexes, [MⅡ(L)2·2H2O], (M = Cu, Ni or Cd; HL = 4-(3,4-dichlorophenyl)piperazine-1-carboxylic acid)were synthesized and structurally determined by single-crystal X-ray diffraction. Molecular docking study preliminarily revealed that complex 1 had potential urease inhibitory activity. In accordance with the result of calculation, in vitro tests of the inhibitory activities of complexes 1-3 against jack bean urease showed complex 1 (IC50 = 8.17 ± 0.91 μM) had better inhibitory activities than the positive reference acetohydroxamic acid (AHA) (IC50 = 26.99 ± 1.43 μM), while complexes 2 and 3 showed no inhibitory activities., kinetics study was carried out to explore the mechanism of the inhibiting of the enzyme, and the result indicated that complex 1 was a competitive inhibitor of urease. Albumin binding experiment and in vitro toxicity evaluation of complex 1 were implemented to explore its Pharmacological properties.

  4. Thermodynamics of Carboxyl Group′s Protonation of α -amino Acids in Water-Ethanol Mixtures at 298.15K%α-氨基酸在水-乙醇中羧基质子化热力学

    Institute of Scientific and Technical Information of China (English)

    厉刚; 林瑞森; 宗汉兴

    2000-01-01

    Enthalpy changes for the protonation of carboxyl group of four α-amino acids(glycine,L-α-alanine,L-valine and L-serine) were measured in water-ethanol mixtures (10- 70wt%) at 298.15K using LKB-2277 Bioactivity Monitor.The corresponding entropy and Gibbs energy changes were also calculated.The results show that both enthalpy changes and entropy changes are favorable to the protonation of carboxyl groups of the investigated amino acids in water-ethanol mixtures.However,the influence of the composition of ethanol in the mixed solvents on the enthalpy change and entropy changes is complicated.Both sδ and sδ ,the differences of enthalpy changes and entropy changes in mixed solvents and in pure water respectively,show a minimum approximately at xEtOH=0.1.The effects of side chains on the enthalpy change and entropy changes were also investigated using the proton transfer process between glycine and the other three amino acids.The results demonstrate that the proton transfer processes for alanine and valine are spontaneous but not for serine,which could be interpreted in terms of the electrostatic interaction between amino group and carboxyl group within the molecule and the interaction between carboxyl group and the solvent.

  5. Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid

    Directory of Open Access Journals (Sweden)

    Keum CG

    2011-10-01

    Full Text Available Chang-Gu Keum1*, Young-Wook Noh1*, Jong-Suep Baek1, Ji-Ho Lim1, Chan-Ju Hwang1, Young-Guk Na1, Sang-Chul Shin2, Cheong-Weon Cho11College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Gungdong, Yuseonggu, Daejeon, South Korea; 2College of Pharmacy, Chonnam National University, Yongbongdong, Buggu, Gwangju, South Korea *These authors contributed equally to this work Background: Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA, are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Methods: Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2–5 minutes of sonication time, 70–130 W sonication power, and 5–25 mg drug loading. Results: A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20

  6. 启发式教学法在有机化学“羧酸及其衍生物”教学中的应用%Heuristic Approach Their Derivatives in Carboxylic Acids and of Organic Chemistry

    Institute of Scientific and Technical Information of China (English)

    李长恭

    2012-01-01

    This paper is a description of the application of heuristic method on carboxylic acid and their derivatives of Organic Chemistry. After bringing forward the discussing topics, such as the activities of carbonyl, a-hydrogen and acidity related to carboxylic acid, the students are directed to compare the corresponding bond length of methanoic acid with formaldehyde and methanol. Focusing on carbon-oxygen bond length in the methanoic acid, which is between carbon-oxygen double bond and carbon-oxygen single bond, the students have comprehended the super-conjugated structure characteristic of carboxylic acid and the chemical property of carboxylic acid could be deduced based on structure understanding. Encouraged by director, the students' interest is greatly enhanced and good results have been achieved.%本文介绍了启发式教学法在有机化学"羧酸及其衍生物"课堂教学中的应用。在总结前期学习内容的基础上,针对羧酸分子中羰基活泼性,α-氢的活泼性及酸性等问题,我引导学生从比较甲酸与甲醛和甲醇分子结构入手,紧紧围绕甲酸分子结构中介于碳-氧双键与碳-氧单键之间的碳-氧键长,分析甲酸分子结构的特点,定性地解答甲酸与甲醛和甲醇化学性质的差异性,加深了学生对羧酸结构与化学性质的认识,提高了学生的学习积极性,取得了良好的教学效果。

  7. Kinetic and product studies of Criegee intermediate reactions with halogenated and non-halogenated carboxylic acids and their implications in the troposphere

    Science.gov (United States)

    Chhantyal-Pun, Rabi; Rotavera, Brandon; Eskola, Arkke; Taatjes, Craig; Percival, Carl; Shallcross, Dudley; Orr-Ewing, Andrew

    2016-04-01

    Criegee intermediates are important species formed during the ozonolysis of alkenes. Direct measurement and modelling studies have shown that reactions of stabilized Criegee intermediates with species like SO2 and NO2 may have a significant effect in tropospheric chemistry.[1, 2] Reaction rates of Criegee intermediates with simple carboxylic acids like HCOOH and CH3COOH have been shown to be near the collision limit and may be a significant sink for these otherwise stable species in the atmosphere.[3, 4] Results obtained from our time-resolved Cavity Ring-Down Spectroscopy (CRDS) apparatus[5] for reactions of the Criegee intermediates, CH2OO and (CH3)2COO with various halogenated (CF3COOH, CF3CF2COOH, CClF2COOH and CHCl2COOH) and non-halogenated (HCOOH and CH3COOH) carboxylic acids will be presented, together with Structure Activity Relationship (SAR) based on these observations. Structure characterization of the products from these reactions using the Multiplexed PhotoIonization Mass Spectrometry (MPIMS) apparatus[1,3] as well as implications for Secondary Organic Aerosol (SOA) formation, assessed using the global atmospheric model STOCHEM, will also be discussed. Bibliography 1. O. Welz, J. D. Savee, D. L. Osborn, S. S. Vasu, C. J. Percival, D. E. Shallcross and C. A. Taatjes, Science, 2012, 335, 204-207. 2. C. J. Percival, O. Welz, A. J. Eskola, J. D. Savee, D. L. Osborn, D. O. Topping, D. Lowe, S. R. Utembe, A. Bacak, G. McFiggans, M. C. Cooke, P. Xiao, A. T. Archibald, M. E. Jenkin, R. G. Derwent, I. Riipinen, D. W. K. Mok, E. P. F. Lee, J. M. Dyke, C. A. Taatjes and D. E. Shallcross, Faraday Discuss., 2013, 165, 45-73. 3. O. Welz, A. J. Eskola, L. Sheps, B. Rotavera, J. D. Savee, A. M. Scheer, D. L. Osborn, D. Lowe, A. M. Booth, P. Xiao, M. A. H. Khan, C. J. Percival, D. E. Shallcross and C. A. Taatjes, Angew. Chem. Int. Ed., 2014, 53, 4547-4550. 4. M. D. Hurley, M. P. S. Andersen, T. J. Wallington, D. A. Ellis, J. W. Martin and S. A. Mabury, J. Phys. Chem. A

  8. Optimization of SPE/GC/HPLC Analytical Procedure for Determination of Phenol, Quinones, and Carboxylic Acids in Water Samples

    OpenAIRE

    Katarzyna Bielicka-Daszkiewicz; Monika Hadzicka; Adam Voelkel

    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...

  9. A novel star-shaped poly(carboxylic acid) for resin-modified glass-ionomer restoratives.

    Science.gov (United States)

    Weng, Y; Howard, L; Xie, D

    2014-07-01

    We have developed a novel glass-ionomer cement (GIC) system composed of photo-curable star-shaped poly(acrylic acid-co-itaconic acid)s. These polyacids were synthesized via a chain-transfer radical polymerization using a newly synthesized multi-arm chain-transfer agent. The star-shaped polyacids showed significantly lower viscosities in water as compared to the linear polyacids. Due to the lower viscosities, the molecular weight (MW) of the polyacids can be significantly increased for enhancing the mechanical strengths while keeping the ease of mixing and handling. The effects of MW, GM-tethering ratio, P/L ratio, and aging on the compressive properties of the experimental cements were significant. The light-cured experimental cements showed significantly improved mechanical strengths i.e. 49% in yield strength, 41% in modulus, 25% in CS, 20% in DTS, and 36% in FS, higher than commercial Fuji II LC. After aging in water for 1 month, the compressive strength of the novel light-cured experimental cement reached 343 MPa, which was 34% and 42% higher than Fuji II and Fuji II LC, respectively. This one-month aged experimental cement was also 23% higher than itself after one day aging, indicating that aging in water can significantly enhance salt-bridge formation for this novel star-shaped polyacid-comprised GIC. PMID:24865692

  10. [Determination of 3-methyl-quinoxaline-2-carboxylic acid in animal and aquatic products by ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lü, Hailuan; Wu, Congming; Cheng, Linli; Zhang, Suxia; Shen, Jianzhong

    2012-01-01

    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in animal tissues and aquatic products. The analyte was extracted with 0.2 mol/L hydrochloric acid. The extract was cleaned up on a Bond Elut C18 cartridge. Then the eluate was collected and evaporated to dryness under nitrogen gas at 35 degrees C. The residue was redissolved in acetonitrile containing 0.1% (v/v) formic acid. The identification was performed by multiple reaction monitoring in positive electrospray ionization. The quantification was done by external standard method. The calibration curves showed good linearity within the range of 2-500 microg/L with the correlation coefficients (r2) greater than 0.990. The limits of detection (LODs) of MQCA in pork, swine liver, pig kidney, fish, prawn, and crab were 0.90, 1.51, 0.94, 1.04, 1.62 and 1.80 microg/kg, respectively; and the limits of quantification (LOQs) were 3.00, 5.02, 3.13, 3.46, 5.40 and 6.00 microg/kg, correspondingly. The recoveries of MQCA in animal tissues and aquatic products were 73.6%-89.0% at the spiked levels of 3-100 microg/kg. The intra-day relative standard deviations (RSDs, n = 5) were less than 15%, and inter-day RSDs (n = 3) were less than 20%. The results demonstrated that the sensitivity, accuracy, and precision were fit for the requirements of veterinary drug residue analysis.

  11. Expression of the Gene Encoding the Tetraploid of Carboxyl-terminal Peptide of β-hCG Containing Thirty-seven Amino Acid Residues in E. coli

    Institute of Scientific and Technical Information of China (English)

    王健; 沈卫英; 周清平; 申庆祥

    2000-01-01

    Objective This study was carried out to investigate the possible enhancement of immunogenicity of the carboxyl-terminal peptide of β-hCG which is made up of 37 amino acid residues (109~145) and contains the specific epitope (antigenic determinant) of hCG.Materials & Methods hCGβ-CTP37 tetraploid cDNA was constructed by linking four hCGβ-CTP37 cDNAs together. The product was then subcloned into the E. coli expression vector pQE60 to construct the expression vector pQE60/ (hCGβ-CTP37)4. Recombinant (hCGβ-CTP37 ) 4 was expressed in E. coil-X-blue.Results Western blot analysis showed that the tetraploid of hCGβ-CTP37 had an apparent molecular weight of 20 kD and had relatively stronger anti-hCG antibody-binding activity compared with the diploid from.Conclusion The tetraploid of hCGβ-CTP37 may be a more potent immunogen for raising anti-hCG vaccines for fertility regulation or suppression of tumor.

  12. Interaction of Di-2-pyridylketone 2-pyridine Carboxylic Acid Hydrazone and Its Copper Complex with BSA: Effect on Antitumor Activity as Revealed by Spectroscopic Studies.

    Science.gov (United States)

    Li, Cuiping; Huang, Tengfei; Fu, Yun; Liu, Youxun; Zhou, Sufeng; Qi, Zhangyang; Li, Changzheng

    2016-04-28

    The drug, di-2-pyridylketone-2-pyridine carboxylic acid hydrazone (DPPCAH) and its copper complex (DPPCAH-Cu) exhibit significant antitumor activity. However, the mechanism of their pharmacological interaction with the biological molecule bovine serum albumin (BSA) remains poorly understood. The present study elucidates the interactions between the drug and BSA through MTT assays, spectroscopic methods and molecular docking analysis. Our results indicate that BSA could attenuate effect on the cytotoxicity of DPPCAH, but not DPPCAH-Cu. Data from fluorescence quenching measurements demonstrated that both DPPCAH and DPPCAH-Cu could bind to BSA, with a reversed effect on the environment of tryptophan residues in polarity. CD spectra revealed that the DPPCAH-Cu exerted a slightly stronger effect on the secondary structure of BSA than DPPCAH. The association constant of DPPCAH with BSA was greater than that of DPPCAH-Cu. Docking studies indicated that the binding of DPPCAH to BSA involved a greater number of hydrogen bonds compared to DPPCAH-Cu. The calculated distances between bound ligands and tryptophans in BSA were in agreement with fluorescence resonance energy transfer results. Thus, the binding affinity of the drug (DPPCAH or DPPCAH-Cu) with BSA partially contributes to its antitumor activity; the greater the drug affinity is to BSA, the less is its antitumor activity.

  13. Comparative bioavailability of two oral formulations of clopidogrel: Determination of clopidogrel and its carboxylic acid metabolite (SR26334 under fasting and fed conditions in healthy subjects

    Directory of Open Access Journals (Sweden)

    Brvar Nina

    2014-03-01

    Full Text Available Two randomized, single dose, 2-period, 2-sequence crossover studies were conducted to evaluate the comparative bioavailability of two clopidogrel formulations under fasting and fed conditions. Assessment of bioequivalence was based upon measurement of plasma concentrations of the parent drug, clopidogrel, and its major (inactive metabolite, clopidogrel carboxylic acid, using improved methanol-free extraction. Bioequivalence of Krka’s formulation to the innovator’s formulation was demonstrated under both fasting and fed conditions on 205 volunteers. Confidence intervals for AUC0-t, AUC0-inf and Cmax of clopidogrel and its main metabolite were well within the acceptance range of 80.00 to 125.00 %. Food substantially increased the bioavailability of clopidogrel from both formulations, while no effect of food on the extent and rate of exposure to the metabolite was observed. The effect of food was comparable between the two formulations, as indicated by the same direction and rank of food impact on the bioavailability of both formulations.

  14. 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. PMID:27394000

  15. Detecting quinoxaline-2-carboxylic acid in animal tissues by using sensitive rapid enzyme-linked immunosorbent assay and time-resolved fluoroimmunoassay.

    Science.gov (United States)

    Le, Tao; Yu, Huan; Niu, Xiaodong

    2015-05-15

    An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluoroimmunoassay (TR-FIA) based on an anti-N-butylquinoxaline-2-carboxamide (BQCA) monoclonal antibody were standardized and validated for quinoxaline-2-carboxylic acid (QCA) screening in animal tissues and its performance were compared to HPLC. The sensitivities obtained for edible tissue extracts were 1.62 and 1.12 ng ml(-1) for ic-ELISA and TR-FIA detection, respectively. Two samples were spiked with QCA and analyzed by both methods. The recovery values ranged from 92.6% to 112.2% and the coefficients of variation were less than 15% for QCA spiking into swine tissue samples at concentrations of 2.5-50.0 μg kg(-1). Excellent correlations (r(2)=0.987-0.996) of the ic-ELISA/HPLC and TR-FIA/HPLC data were observed for processed samples. The results demonstrated that the ic-ELISA and TR-FIA methods were rapid and accurate for the residue detection of QCA in animal tissues.

  16. Monoclonal antibody production and indirect competitive enzyme-linked immunosorbent assay development of 3-methyl-quinoxaline-2-carboxylic acid based on novel haptens.

    Science.gov (United States)

    Li, Guopeng; Zhao, Liang; Zhou, Feng; Li, Jiaying; Xing, Yuan; Wang, Tiangang; Zhou, Xilong; Ji, Baoping; Ren, Wanpeng

    2016-10-15

    Two novel immunizing haptens of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) were synthesized and conjugated with cationized bovine serum albumin. Female BALB/c mice were immunized with above conjugates, splenocytes were fused with Sp2/0 cells to produce monoclonal antibody. Compared with previous studies, antibodies raised in this work showed higher sensitivity. Meantime, a novel heterologous coating hapten was also prepared. The indirect competitive enzyme-linked immunosorbent assay (icELISA) based on the optimum condition showed an IC50 of 3.1μg/kg (ppb), and the linear range of 0.46-10.5ppb for MQCA. The limit of detect (LOD) of MQCA in swine muscle, swine liver and chicken was 0.32, 0.54, and 0.28ppb, respectively. The LOD of this assay can satisfy the minimum required performance levels (4ppb) for MQCA. These results indicated that the proposed ELISA, with high sensitivity and specificity, as well as good reproducibility and accuracy, is suitable for determination of MQCA residues in food samples.

  17. 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing rhizobacteria protect Ocimum sanctum plants during waterlogging stress via reduced ethylene generation.

    Science.gov (United States)

    Barnawal, Deepti; Bharti, Nidhi; Maji, Deepamala; Chanotiya, Chandan Singh; Kalra, Alok

    2012-09-01

    Ocimum sanctum grown as rain-fed crop, is known to be poorly adapted to waterlogged conditions. Many a times the crop suffers extreme damages because of anoxia and excessive ethylene generation due to waterlogging conditions present under heavy rain. The usefulness of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth promoting rhizobacteria was investigated under waterlogging stress. The comparison of herb yield and stress induced biochemical changes of waterlogged and non-waterlogged plants with and without ACC deaminase-containing microbiological treatments were monitored in this study. Ten plant growth promoting rhizobacteria strains containing ACC-deaminase were isolated and characterized. Four selected isolates Fd2 (Achromobacter xylosoxidans), Bac5 (Serratia ureilytica), Oci9 (Herbaspirillum seropedicae) and Oci13 (Ochrobactrum rhizosphaerae) had the potential to protect Ocimum plants from flood induced damage under waterlogged glass house conditions. Pot experiments were conducted to evaluate the potential of these ACC deaminase-containing selected strains for reducing the yield losses caused by waterlogging conditions. Bacterial treatments protected plants from waterlogging induced detrimental changes like stress ethylene production, reduced chlorophyll concentration, higher lipid peroxidation, proline concentration and reduced foliar nutrient uptake. Fd2 (A. xylosoxidans) induced maximum waterlogging tolerance as treated waterlogged plants recorded maximum growth and herb yield (46.5% higher than uninoculated waterlogged plants) with minimum stress ethylene levels (53% lower ACC concentration as compared to waterlogged plants without bacterial inoculation) whereas under normal non-waterlogged conditions O. rhizosphaerae was most effective in plant growth promotion. PMID:22846334

  18. Congener-specific organic carbon-normalized soil and sediment-water partitioning coefficients for the C1 through C8 perfluoroalkyl carboxylic and sulfonic acids.

    Science.gov (United States)

    Rayne, Sierra; Forest, Kaya

    2009-11-01

    Organic carbon-normalized soil and sediment-water partitioning coefficients (K(oc)) were estimated for all C(1) through C(8) perfluoroalkyl carboxylic (PFCA) and sulfonic (PFSA) acid congeners. The limited experimental K(oc) data set for the straight chain C(7) through C(10) PFCAs and C(8) and C(10) PFSAs was correlated to SPARC and ALOGPS computationally estimated octanol-water partitioning/distribution constants and used to predict K(oc) values for both branched and linear C(1) through C(8) isomers. Branched and linear congeners in this homologue range are generally expected to have K(oc) values > 1, leading to their accumulation in organic matter on sediments and soils, retardation during ground and pore water flow, and the preferential association with dissolved organic matter in aquatic systems. Both increasing perfluoroalkyl chain length and linearity increase K(oc) values with substantial intra- and inter-homologue variation and interhomologue mixing. Variability in K(oc) values among the PFCA and PFSA congeners will likely lead to an enrichment of more linear and longer-chain isomers in organic matter fractions, resulting in aqueous phases fractionated towards shorter-chain branched congeners. The expected magnitude of fractionation will require inclusion in source apportionment models and risk assessments. A comparison of representative established quantitative structure property relationships for estimating K(oc) values from octanol-water partitioning constants suggests that these equilibrium partitioning frameworks may be applicable towards modeling PFCA and PFSA environmental fate processes. PMID:20183495

  19. Biocontrol of Potato Common Scab is Associated with High Pseudomonas fluorescens LBUM223 Populations and Phenazine-1-Carboxylic Acid Biosynthetic Transcript Accumulation in the Potato Geocaulosphere.

    Science.gov (United States)

    Arseneault, Tanya; Goyer, Claudia; Filion, Martin

    2016-09-01

    Pseudomonads are often used as biocontrol agents because they display a broad range of mechanisms to control diseases. Common scab of potato, caused by Streptomyces scabies, was previously reported to be controlled by Pseudomonas fluorescens LBUM223 through phenazine-1-carboxylic acid (PCA) production. In this study, we aimed at characterizing the population dynamics of LBUM223 and the expression of phzC, a key gene involved in the biosynthesis of PCA, in the rhizosphere and geocaulosphere of potato plants grown under controlled and field conditions. Results obtained from controlled experiments showed that soil populations of LBUM223 significantly declined over a 15-week period. However, at week 15, the presence of S. scabies in the geocaulosphere was associated with significantly higher populations of LBUM223 than when the pathogen was absent. It also led to the detection of significantly higher phzC gene transcript numbers. Under field conditions, soil populations of LBUM223 followed a similar decline in time when a single inoculation was applied in spring but remained stable when reinoculated biweekly, which also led to greater phzC gene transcripts accumulation. Taken together, our findings suggest that LBUM223 must colonize the potato geocaulosphere at high levels (10(7) bacteria/g of soil) in order to achieve biocontrol of common scab through increased PCA production. PMID:27088392

  20. Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution-2: Effects of nuclear fragmentation and its simulation with PHITS

    Energy Technology Data Exchange (ETDEWEB)

    Maeyama, Takuya [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Yamashita, Shinichi; Taguchi, Mitsumasa [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Baldacchino, Gerard [CEA Saclay, IRAMIS, UMR 3299 CEA-CNRS SIS2M, Laboratoire de Radiolyse, F-91191 Gif sur Yvette Cedex (France); Sihver, Lembit [Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Department of Nuclear Engineering, Texas A and M University, TX 77843-3133 (United States); Department of Roanoke College, Salem, VA 24153 (United States); Department of Nuclear Engineering, Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Murakami, Takeshi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nuclear Professional School, School of Engineering, University of Tokyo, 2-22 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2011-12-15

    The G(OH) values in aqueous coumarin-3-carboxylic-acid (3-CCA) solutions irradiated with {sup 12}C{sup 6+} beams having the energies of 135, 290 and 400 MeV/u were measured by a fluorescent method around the Bragg peak, with 0.6 mm intervals, and quartz cells of 1 cm optical lengths, at the Heavy Ion Medical Accelerator in Chiba, National Institute of Radiological Sciences (NIRS). For each ion, the G(OH) has been calculated as a function of dose average LET and position. The calculated results have been compared to measurements, and the results, reproducibility and reliability of the calculations are discussed in the paper. - Highlights: > Therapeutic ion beam has energy of several hundred MeV/u because it is necessary for a few tens cm range. > With such high energy, nuclear fragmentations of carbon ions occur resulting in production of lighter ions. > In this study, OH yield in water radiolysis near the Bragg peak of therapeutic ion beams was measured. > Measured yields are discussed considering nuclear fragmentation by PHITS code.