Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds.

Science.gov (United States)

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-06-15

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N-H groups are tolerated on the barbituric acid, with no complications arising from N-H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Menthone aryl acid hydrazones: a new class of anticonvulsants.

Science.gov (United States)

Jain, Jainendra; Kumar, Y; Sinha, Reema; Kumar, Rajeev; Stables, James

2011-01-01

A series of ten compounds (Compounds J(1)-J(10)) of (±) 3-menthone aryl acid hydrazone was synthesized and characterized by thin layer chromatography and spectral analysis. Synthesized compounds were evaluated for anticonvulsant activity after intraperitoneal (i.p) administration to mice by maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure method and minimal clonic seizure test. Minimal motor impairment was also determined for these compounds. Results obtained showed that four compounds out of ten afforded significant protection in the minimal clonic seizure screen at 6 Hz. Compound J(6), 4-Chloro-N-(2-isopropyl-5-methylcyclohexylidene) benzohydrazide was found to be the most active compound with MES ED(50) of 16.1 mg/kg and protective index (pI) of greater than 20, indicating that (±) 3-menthone aryl acid hydrazone possesses better and safer anticonvulsant properties than other reported menthone derivatives viz. menthone Schiff bases, menthone semicarbazides and thiosemicarbazides.

Investigation of the luminescent properties of terbium-anthranilate complexes and application to the determination of anthranilic acid derivatives in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Arnaud, N.; Georges, J

2003-01-10

The luminescent properties of terbium complexes with furosemide (FR), flufenamic (FF) acid, tolfenamic (TF) acid and mefenamic (MF) acid have been investigated in aqueous solutions. For all four compounds, complexation occurs when the carboxylic acid of the aminobenzoic group is dissociated and is greatly favoured in the presence of trioctylphosphine oxide as co-ligand and Triton X-100 as surfactant. Under optimum conditions, luminescence of the lanthanide ion is efficiently sensitised and the lifetime of the {sup 5}D{sub 4} resonance level of terbium in the complex is ranging between 1 and 1.9 ms, against 0.4 ms for the aqua ion. The sensitivity of the method for the determination of anthranilic acid derivatives is improved by one to two orders of magnitude with respect to that achieved using native fluorescence or terbium-sensitised luminescence in methanol. The limits of detection are 2x10{sup -10}, 5x10{sup -10} and 2x10{sup -9} mol l{sup -1} for flufenamic acid, furosemide and tolfenamic acid, and mefenamic acid, respectively, with within-run RSD values of less than 1%. The method has been applied to the determination of flufenamic acid in spiked calf sera with and without sample pretreatment. Depending on the method and the analyte concentration, the recovery was ranging between 83 and 113% and the lowest concentration attainable in serum samples was close to 1x10{sup -7} mol l{sup -1}.

Utilization of acidic α-amino acids as acyl donors: an effective stereo-controllable synthesis of aryl-keto α-amino acids and their derivatives.

Science.gov (United States)

Wang, Lei; Murai, Yuta; Yoshida, Takuma; Okamoto, Masashi; Tachrim, Zetryana Puteri; Hashidoko, Yasuyuki; Hashimoto, Makoto

2014-05-16

Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

Capillary electrophoresis determination of glucosamine in nutraceutical formulations after labeling with anthranilic acid and UV detection.

Science.gov (United States)

Volpi, Nicola

2009-04-05

A new robust CE method for the determination of the glucosamine (GlcN) content in nutraceutical formulations is described after its derivatization with anthranilic acid (2-aminobenzoic acid, AA). The CE separation of derivatized GlcN with AA was performed on an uncoated fused-silica capillary tube (50 microm I.D.) using an operating pH 7.0 buffer of 150 mM boric acid/50 mM NaH2PO4 and UV detection at 214 nm. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The detector response for GlcN was linear over the selected concentration range from 240 to 2400 pg (40-400 microg/mL) with a correlation coefficient greater than 0.980. The intra- and inter-day variations (CV%) were between 0.5 and 0.9 for migration time, and between 2.8 and 4.3 for peak area, respectively. The LOD and the LOQ of the method were approximately 200 and 500 pg, respectively. The intra- and inter-day accuracy was estimated to range from 2.8% to 5.1%, while the percent recoveries of GlcN in formulations were calculated to be about 100% after simple centrifugation for 10 min, lyophilization and derivatization with AA. The CE method was applied to the determination of GlcN content, in the form of GlcN-hydrochloride or GlcN-sulfate, of several nutraceutical preparations in the presence of other ingredients, i.e. chondroitin sulfate, vitamin C and/or methylsulfonylmethane (MSM) as well as salts and other agents. The quantitative results obtained were in total conformity with the label claims.

N-Aryl Arenedicarboximides as Tunable Panchromatic Dyes for Molecular Solar Cells

Directory of Open Access Journals (Sweden)

Zhi Cao

2010-01-01

Full Text Available Three organic dyes designed as molecular dyads were prepared that feature a common naphthalimide acceptor and N-aryl donors. One of these incorporated an additional cyanoacrylic acid linker and conjugated thiophene bridge inserted between donor and acceptor groups. Electrochemical and photochemical characterizations have been carried out on nanocrystalline TiO2 dye-sensitized solar cells which were fabricated with these dyes as the sensitizing component. HOMO and LUMO energies were also calculated using TDDFT methods and validated by the cyclic voltammetry method. A key finding from this study indicates that computational methods can provide energy values in close agreement to experimental for the N-aryl-naphthalimide system. Relative to HOMO/LUMO energy levels of N719, the dyes based on naphthalimide chromophore are promising candidates for metal-free DSSCs.

Mechanistic Studies on the Copper-Catalyzed N-Arylation of Amides

Science.gov (United States)

Strieter, Eric R.; Bhayana, Brijesh; Buchwald, Stephen L.

2009-01-01

The copper-catalyzed N-arylation of amides, i.e., the Goldberg reaction, is an efficient method for the construction of products relevant to both industry and academic settings. Herein, we present mechanistic details concerning the catalytic and stoichiometric N-arylation of amides. In the context of the catalytic reaction, our findings reveal the importance of chelating diamine ligands in controlling the concentration of the active catalytic species. The consistency between the catalytic and stoichiometric results suggest that the activation of aryl halides occurs through a 1,2-diamine-ligated copper(I) amidate complex. Kinetic studies on the stoichiometric N-arylation of aryl iodides using 1,2-diamine ligated Cu(I) amidates also provide insights into the mechanism of aryl halide activation. PMID:19072233

Selective copper catalysed aromatic N-arylation in water

DEFF Research Database (Denmark)

Engel-Andreasen, Jens; Shimpukade, Bharat; Ulven, Trond.

2013-01-01

4,7-Dipyrrolidinyl-1,10-phenanthroline (DPPhen) was identified as an efficient ligand for copper catalyzed selective arom. N-arylation in water. N-Arylation of indoles, imidazoles and purines proceeds with moderate to excellent yields and complete selectivity over aliph. amines. Aq. medium...

Efficient one-pot, four-component synthesis of N,N-dibenzyl-N-{1-[5-(3-aryl-1,3,4-oxadiazol-2-yl]cyclobutyl}amine derivatives from the reaction of (isocyanoiminotriphenylphosphorane, dibenzylamine, an aromatic carboxylic acid and cyclobutanone

Directory of Open Access Journals (Sweden)

Shajari Nahid

2012-01-01

Full Text Available Four-component reaction of cyclobutanone, dibenzylamine and (Nisocyanimino triphenylphosphorane in the presence of aromatic carboxylic acids proceed smoothly at room temperature and under neutral conditions to afford N,N-dibenzyl-N-{1-[5-(3-aryl-1,3,4-oxadiazol-2-yl]cyclobutyl}amine derivatives in high yields.

Palladium-catalysed arylation of acetoacetate esters to yield 2-arylacetic acid esters

CSIR Research Space (South Africa)

Zeevaart, JG

2004-05-24

Full Text Available , was developed simultaneously by Hart- wig and Buchwald.5 Typically the tert-butyl ester of propionic acid is treated with an aryl halide (bromide or chloride) in the presence of a strong base, palladium and a bulky phosphine ligand or a bulky imidazolinium CO2t... novel palladium- catalysed conditions for the arylation of acetoacetate esters resulting in the formation of 2-arylacetic acid esters. When we attempted the arylation of tert-butyl aceto- acetate 1a with bromobenzene 2a using mild reaction conditions (K3...

A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides

Directory of Open Access Journals (Sweden)

Milton Edward J

2007-05-01

Full Text Available Abstract A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

Diversification of indoles via microwave-assisted ligand-free copper-catalyzed N-arylation

Energy Technology Data Exchange (ETDEWEB)

Kwon, Jae Kwan; Lee, Jin Hee; Kim, Tae Sung; Yum, Eul Kgun [Dept. of Chemistry, Chu ngnam National University, Daejon (Korea, Republic of); Park, Jee Jung [Western Seoul Center Korea Basic Science Institute, Seoul (Korea, Republic of)

2016-12-15

A simple, efficient Cu{sub 2}O catalyst system under microwave irradiation was developed for N-arylation of various indoles without ligands and additives. Diverse N-heteroarylated indoles were prepared by coupling indoles with various heteroaryl halides within 1 h. The selective reactivity of bromoindole with aryl iodide provided N-aryl bromoindoles, which could be useful intermediates for palladium-catalyzed Heck and Suzuki coupling reactions.

Copper-Catalyzed N-Arylation of Amides Using (S-N-Methylpyrrolidine-2-carboxylate as the Ligand

Directory of Open Access Journals (Sweden)

Dong-Sheng Ma

2010-03-01

Full Text Available (S-N-methylpyrrolidine-2-carboxylate, a derivative of natural L-proline, was found to be an efficient ligand for the copper-catalyzed Goldberg-type N-arylation of amides with aryl halides under mild conditions. A variety of N-arylamides were synthesized in good to high yields.

Interaction of model aryl- and alkyl-boronic acids and 1,2-diols in aqueous solution.

Science.gov (United States)

Marinaro, William A; Prankerd, Richard; Kinnari, Kaisa; Stella, Valentino J

2015-04-01

The goal of this work was to quantitate ester formation between alkyl and aryl boronic acids and vicinal-diols or 1,2-diols in aqueous solution. As used here, 1,2-diols includes polyols with one or more 1,2-diol pairs. Multiple techniques were used including apparent pKa shifts of the boronic acids using UV spectrophotometry (for aryl acids) and titration (for aryl and alkyl acids). Isothermal microcalorimetry was also used, with all reactions being enthalpically favored. For all the acids and 1,2-diols and the conditions studied, evidence only supported 1:1 ester formation. All the esters formed were found to be significantly more acidic, as Lewis acids, by 3-3.5 pKa units than the corresponding nonesterified boronic acid. The equilibrium constants for ester formation increased with increasing number of 1,2-diol pairs but stereochemistry may also play a role as sorbitol with five possible 1,2-diol pairs and five isomers (taking into account the stereochemistry of the alcohol groups) was twice as efficient at ester formation compared with mannitol, also with five possible 1,2-diol pairs but only three isomers. Alkyl boronic acids formed esters to a greater extent than aryl acids. Although some quantitative differences were seen between the various techniques used, rank ordering of the structure/reactivity was consistent. Formulation implications of ester formation between boronic acids and 1,2-diols are discussed. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

New high-performance liquid chromatography assay for glycosyltransferases based on derivatization with anthranilic acid and fluorescence detection.

Science.gov (United States)

Anumula, Kalyan Rao

2012-07-01

Assays were developed using the unique labeling chemistry of 2-aminobenzoic acid (2AA; anthranilic acid, AA) for measuring activities of both β1-4 galactosyltransferase (GalT-1) and α2-6 sialyltransferase (ST-6) by high-performance liquid chromatography (HPLC) with fluorescence detection (Anumula KR. 2006. Advances in fluorescence derivatization methods for high-performance liquid chromatographic analysis of glycoprotein carbohydrates. Anal Biochem. 350:1-23). N-Acetylglucosamine (GlcNAc) and N-acetyllactosamine were used as acceptors and uridine diphosphate (UDP)-galactose and cytidine monophosphate (CMP)-N-acetylneuraminic acid (NANA) as donors for GalT-1 and ST-6, respectively. Enzymatic products were labeled in situ with AA and were separated from the substrates on TSKgel Amide 80 column using normal-phase conditions. Enzyme units were determined from the peak areas by comparison with the concomitantly derivatized standards Gal-β1-4GlcNAc and NANA-α2-6 Gal-β1-4GlcNAc. Linearity (time and enzyme concentration), precision (intra- and interassay) and reproducibility for the assays were established. The assays were found to be useful in monitoring the enzyme activities during isolation and purification. The assays were highly sensitive and performed equal to or better than the traditional radioactive sugar-based measurements. The assay format can also be used for measuring the activity of other transferases, provided that the carbohydrate acceptors contain a reducing end for labeling. An assay for glycoprotein acceptors was developed using IgG. A short HPLC profiling method was developed for the separation of IgG glycans (biantennary G0, G1, G2, mono- and disialylated), which facilitated the determination of GalT-1 and ST-6 activities in a rapid manner. Furthermore, this profiling method should prove useful for monitoring the changes in IgG glycans in clinical settings.

Design and synthesis of aryl ether and sulfone hydroxamic acids as potent histone deacetylase (HDAC) inhibitors.

Science.gov (United States)

Pabba, Chittari; Gregg, Brian T; Kitchen, Douglas B; Chen, Zhen Jia; Judkins, Angela

2011-01-01

A series of novel hydroxamic acid based histone deacetylases (HDAC) inhibitors with aryl ether and aryl sulfone residues at the terminus of a substituted, unsaturated 5-carbon spacer moiety have been synthesized for the first time and evaluated. Compounds with meta- and para-substitution on the aryl ring of ether hydroxamic acids 19c, 20c, 19e, 19f and 19g are potent HDAC inhibitors with activities at low nanomolar levels. Copyright © 2010 Elsevier Ltd. All rights reserved.

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

Directory of Open Access Journals (Sweden)

Andrea Caporale

2014-02-01

Full Text Available Two efficient protocols for the palladium-catalyzed synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc2 and P(p-tol3 using DBU as the base and THF as the solvent was found to be highly effective for the coupling reaction of 2-methyl-3-butyn-2-ol (4 with a wide range of aryl bromides in good to excellent yields. Analogously, the synthesis of aryl-2-methyl-3-butyn-2-ols was performed also through the decarboxylative coupling reaction of 4-hydroxy-4-methyl-2-pentynoic acid with aryl bromides, using a catalyst containing Pd(OAc2 in combination with SPhos or XPhos in the presence of tetra-n-butylammonium fluoride (TBAF as the base and THF as the solvent. Therefore, new efficient approaches to the synthesis of terminal acetylenes from widely available aryl bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described.

Unique anthranilic acid chemistry facilitates profiling and characterization of Ser/Thr-linked sugar chains following hydrazinolysis.

Science.gov (United States)

Anumula, Kalyan Rao

2008-02-01

A novel method for the analysis of Ser/Thr-linked sugar chains was made possible by the virtue of unique anthranilic acid (AA, 2-aminobenzoic acid [2AA]) chemistry for labeling carbohydrates in aqueous salt solutions (K. R. Anumula, Anal. Biochem. 350 (2006) 1-23). The protocol for profiling of Ser/Thr carbohydrates by hydrazinolysis was made simple by eliminating intermediary isolation steps involved in a sample preparation such as desalting and various chromatographic purification schemes. A 6-h hydrazinolysis was carried out at 60 degrees C for O-linked oligosaccharides and at 95 degrees C for total oligosaccharides (N-linked with some O-linked). Following evaporation of hydrazine (<10 min), the oligosaccharides were N-acetylated and derivatized with AA in the same reaction mixture containing salts. Presumably, the glycosyl-hydrazines/hydrazones present in the mixture did not interfere with AA labeling. Because AA is the most fluorescent and highly reactive tag for labeling carbohydrates, the procedures described are suitable for the analysis of a limited amount of samples ( approximately 5 microg) by the current high-resolution high-performance liquid chromatography (HPLC) methods. HPLC conditions developed for the separation of O-linked sugar chains based on size on an amide column were satisfactory for quantitative profiling and characterization. Common O-linked sugar chains found in fetuin, equine chorionic gonadotropin, and glycophorin can be analyzed in less than 50 min. In addition, these fast profiling methods were comparable to profiling by PNGase F (peptide N-glycosidase from Flavobacterium meningosepticum) digestion in terms of time, effort, and simplicity and also were highly reproducible for routine testing. The procedures for the release of sugar chains by hydrazinolysis at the microgram level, labeling with fluorescent tag AA, and profiling by HPLC should be useful in characterization of carbohydrates found in glycoproteins.

Dianthosaponins G-I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity.

Science.gov (United States)

Kanehira, Yuka; Kawakami, Susumu; Sugimoto, Sachiko; Matsunami, Katsuyoshi; Otsuka, Hideaki

2016-10-01

Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G-I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated.

Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

Science.gov (United States)

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-01-01

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes

Directory of Open Access Journals (Sweden)

Jimena E. Díaz

2016-09-01

Full Text Available The first general procedure for the synthesis of 5 to 7-membered 1-aryl-2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a chloroformic solution of ethyl polyphosphate (PPE. The use of trimethylsilyl polyphosphate (PPSE in solvent-free conditions allowed for the synthesis of 1-aryl-2-iminopiperidines and hitherto unreported 1-aryl-2-iminoazepanes. The cyclization reaction involves good to high yields and short reaction times, and represents a novel application of PPA esters in heterocyclic synthesis.

N-aryl pyrrolo-tetrathiafulvalene based ligands: synthesis and metal coordination.

Science.gov (United States)

Balandier, Jean-Yves; Chas, Marcos; Dron, Paul I; Goeb, Sébastien; Canevet, David; Belyasmine, Ahmed; Allain, Magali; Sallé, Marc

2010-03-05

A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, reminiscent of the corresponding MPTTF derivatives, are provided. When the aryl group is a binding pyridyl unit, the MPTTF derivative 10a can coordinate M(II) salts (M = Pt, Pd). The first examples of metal-directed orthogonal MPTTF-based dimers 11-14, obtained through coordination of 10a to cis-blocked square planar Pt or Pd complexes are described. Studies on the parameters influencing the dimer construction are presented, as well as first recognition properties of the resulting electron-rich clip for C(60).

Metal complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid and benzohydroxamic acid. Crystal and molecular structure of [Cu(phen)2(Cl)]Cl x H2Sha, a model for a peroxidase-inhibitor complex.

Science.gov (United States)

O'Brien, E C; Farkas, E; Gil, M J; Fitzgerald, D; Castineras, A; Nolan, K B

2000-04-01

Stability constants of iron(III), copper(II), nickel(II) and zinc(II) complexes of salicylhydroxamic acid (H2Sha), anthranilic hydroxamic acid (HAha) and benzohydroxamic acid (HBha) have been determined at 25.0 degrees C, I=0.2 mol dm(-3) KCl in aqueous solution. The complex stability order, iron(III) > copper(II) > nickel(II) approximately = zinc(II) was observed whilst complexes of H2Sha were found to be more stable than those of the other two ligands. In the preparation of ternary metal ion complexes of these ligands and 1,10-phenanthroline (phen) the crystalline complex [Cu(phen)2(Cl)]Cl x H2Sha was obtained and its crystal structure determined. This complex is a model for hydroxamate-peroxidase inhibitor interactions.

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

Directory of Open Access Journals (Sweden)

Burkhard Koenig

2011-01-01

Full Text Available N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald–Hartwig-type reactions, copper-mediated Ullmann-type and Chan–Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan–Lam reactions. Chan–Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald–Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C–N bond formation in the course of a total synthesis or drug synthesis.

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.

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B

Science.gov (United States)

Verma, Neelam; Mittal, Minakshi; Verma, Raman kumar

2008-01-01

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Analytical application of aminohydroxamic acids

International Nuclear Information System (INIS)

Fadl Elmoula, Abd ELfatah Abdella

2000-11-01

Anthranilic hydroxamic acid was prepared by coupling of methylanthranilate (prepared by esterification of anthranilic acid with methyl alcohol using the fisher-speir method) with freshly prepared hydroxylamine. The lignad was characterized by the usual reaction of hydroxamic acid with acidic V(V) and Fe(III) solutions that gives blood-red colour in amyl alcohol and deep-violet colour in aqueous solution, respectively. The absorbance of Fe(III)-hydroxamic acids complexes increases with increase of pH. In this study, the effect of pH on the absorbance of Fe(III)-anthranilic hydroxamic acid was in accordance with this trend. The maximum absorbance was obtained at pH 5.0 at maximum wavelength of 482 nm. For Cu(II)-anthranilic hydroxamic acid complex, the use of acidic basic pH lead to precipitation of Cu(II)-ligand complex. But when using buffer pH (acetic acid/sodium acetate) a clear green colour of Cu(II)-ligand complex was obtained. The maximum wavelength of 390 nm. V(V)-anthranilic hydroxamic acid complex was extracted in acidic medium in amyl alcohol at pH 2.0 because in aqueous solution V(V)-anthranilic hydroxamic acid complex has not clear colour. It was observed the the maximum extraction in acidic medium decrease sharply with the increasing of pH value. The maximum wavelength for maximum absorbance was recorded at 472 nm. V(V) interfered with determination of Fe(III)) above concentration of 2 ppm, whereas Cu(II) interferes slightly with the determination of Fe(III) ions even at a high concentration of the Cu(II) ions. Both Cu(II) and Ni(II) do not interfere with the determination of V(V) ions even at high concentrations, Fe(III) ion produced slight interference, while Mo(VI) ions have a pronounced interference. Both V(V) and Fe(III) ions interfered markedly with the determination of Cu(II) ions, and made impractical under conditions. However, the calibration curves for the three metal ions produced a practical linear dynamic range.(Author)

Induction of the p75NTR by Aryl Propionic Acids in Prostate Cancer Cells

National Research Council Canada - National Science Library

Quann, Emily

2007-01-01

.... I have found that treatment of prostate cancer cells with the aryl propionic acids R-flurbiprofen and ibuprofen induces reexpression of p75NTR, decreases cell survival, and increases apoptosis...

High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

Science.gov (United States)

Anumula, K R; Dhume, S T

1998-07-01

Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods

Bromosubstituted aryl hydroxamic acids and their analytical application towards some transition metals

International Nuclear Information System (INIS)

Mohamed, Salah Elnaiem

1997-01-01

Four aryl substituted hydroxamic acids were prepared: N-phenyl-N-p-bromobenzohydroxamic acid, N-phenyl-N-o-bromobenzohydroxamic acid, p-methyl-N-phenyl-N-p-bromobenzohydroxamic acid and P-methyl-N-phenyl-N-o-bromobenzohydroxamic acid by the reaction of β-phenylhydroxylamine and p-methyl-β phenylhydroxylamine with the corresponding acid chloride. The acids were identified by their melting points, elemental analysis (nitrogen and bromine contents), infrared and ultraviolet absorption in chloroform, as well as reactions towards acidic solutions of vanadium (V) and iron (III) to give violet and blood-red coulured complexes in the chloroform layer respectively. The extractability of these acids towards chromium (VI), molybdenum (VI), iron (III), vanadium (V), copper (II) and cobalt (II) was investigated. N-phenyl-N-p-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 96.00% at 1M H 2 SO 4 , molybdenum (VI) 87.00% at pH 1, iron (III) 73.90% at pH 4, vanadium (V) 93.00% at pH 1, cobalt (II) 83.10 at pH 8 and copper (II) 93.80% at pH 6. N-phenyl-N-o-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 97.00% at 1M H 2 SO 4 , molybdenum (VI) 92.70% at pH 1, iron (III) 71.20% at pH 4, vanadium (V) 90.00% at pH 1, cobalt (II) 54.70% at pH 7 and copper (II) 86.50% at pH 5. P-methyl-N-phenyl-N-p-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 98.70% at 1M H 2 SO 4 , molybdenum (VI) 74.00% at pH 1, iron (III) 69.60% at pH 5, vandium (V) 76.00% at pH 1, cobalt (II) 51.20% at pH 8 and copper (II) 82.20% at pH 5. P-methyl-N-phenyl-N-o-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 51.00% at 1M H 2 SO 4 , molybdenum (VI) 84.70% at pH 1, iron (III) 66.00% at pH 4, vandium (V) 88.00% at pH 1, cobalt (II) 50.00% at pH 7 and copper (II) 78.6% at pH 6. Twenty four of hydroxamic acids complexes of Cr (VI), Mo (VI), V (V), Fe (III), Co (II) and Cu (II) were prepared by the reaction of these acids with the six

Simple preparation of new N-aryl-N-(3-indolmethyl acetamides and their spectroscopic analysis

Directory of Open Access Journals (Sweden)

José A. Henao

2009-12-01

Full Text Available To prepare new indolic molecules and characterize them by spectroscopic methods. Materials and methods: All reagentswere purchased from Aldrich, commercial grade. The purity of the products and the composition of the reaction mixtures were monitoredby thin layer chromatography over Silufol UV254 0.25 mm-thick chromatoplates. Product isolation and purification were performed bycolumn chromatography (SiO2, using ethyl acetate-petroleum ether mixtures as eluents. Results. The synthesis of new N-aryl-N-(3-indolmethyl acetamides based on first step iminization reaction of indol-3-carbaldehyde is accomplished. The structures of the C-3substituted indoles were confirmed by 1H-NMR and 13C-NMR studies supported by inverse-detected 2D NMR experiments and alsothrough monocrystal X-ray diffraction. Conclusions. An efficient, economic, and fast synthetic route was designed to the construction ofthe N-aryl-N-(3-indolmethyl acetamides, structural analogues of some alkaloids.

Solvent-Free Synthesis of Aryl Iodide Using Nano SiO2/HIO4 as a Reusable Acid Catalyst

Directory of Open Access Journals (Sweden)

A. Bamoniri

2014-07-01

Full Text Available An efficient and environmentally benign   method for the synthesis of aryl iodides have been developed by diazotization of aromatic amines with NaNO2 and nanosilica periodic acid (nano-SPIA as a green catalyst via grinding followed by a sandmeyer iodination by KI under solvent-free conditions at room temperature. The ensuing aryl diazonium salts supported on nano-SPIA were sufficiently stable to be kept at room temperature in the dry state. This method is a novel, efficient, eco-friendly route for solvent-free synthesis of aryl iodides.

Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

Science.gov (United States)

Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

2017-04-01

Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

Directory of Open Access Journals (Sweden)

Elizabeth P. Jones

2011-11-01

Full Text Available A method was developed for the synthesis of α-alkyl, α-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave the corresponding valine dipeptides from bulkier bislactims.

SYNTHESIS AND STUDY OF ANTIOXIDANT ACTIVITY OF [(1-ARYL-5-FORMYL-1H-IMIDAZOLE-4-ILTHIO]PROPIONIC ACIDS

Directory of Open Access Journals (Sweden)

A. O. Palamar

2014-12-01

Full Text Available Introduction. Derivatives of imidazole belong to the promising group of compounds for antioxidant activity study, due to the series of recent publications. This is defined by special features of their structure, specific reactivity and significant potential of pharmacological action. Earlier during process of looking for new antioxidants we studied significant amount of imidazole derivatives, among which the [(1-aryl-5-formylimidazole-4-ilthio]acetic acids structurally modified by the formyl group and thioacetic acid fragment, are especially worth noting. The purpose of the study. Synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids and comparison of their antioxidant effect with [(1-aryl-5-formylimidazole-4-ilthio]acetic acids with to identify prospects of in-depth study of the most active compounds as antioxidants. Materials and methods. The method based on interaction of available 4-chloro-5-formylimidazoles with thiopropionic acid was proposed for the synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids. The reaction takes place in ethanol in presence of potassium hydroxide and leads to the target compounds with yields of 81-86%. The study of antioxidant activity of synthesized compounds was conducted in vitro by speed inhibition value of rats’ liver endogenous lipids ascorbate-dependent peroxide oxidation. It was determined by concentration of one of the final products of free radical oxidation of lipids (FROL – maleic aldehyde (MA in the investigated sample. Concentrations of synthesized compounds were chosen within concentrations which were studied for thiotriazolin (manufactured by corporation “Arterium”, Ukraine, solution for injection, 25 mg/ml. The results of the study and their discussion. Preparative method for the synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids has been designed. Imidazolylthiopropionic acids have been synthesized; they are crystalline compounds, of light

Bromosubstituted aryl hydroxamic acids and their analytical application towards some transition metals

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Salah Elnaiem [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

1997-07-01

Four aryl substituted hydroxamic acids were prepared: N-phenyl-N-p-bromobenzohydroxamic acid, N-phenyl-N-o-bromobenzohydroxamic acid, p-methyl-N-phenyl-N-p-bromobenzohydroxamic acid and P-methyl-N-phenyl-N-o-bromobenzohydroxamic acid by the reaction of {beta}-phenylhydroxylamine and p-methyl-{beta} phenylhydroxylamine with the corresponding acid chloride. The acids were identified by their melting points, elemental analysis (nitrogen and bromine contents), infrared and ultraviolet absorption in chloroform, as well as reactions towards acidic solutions of vanadium (V) and iron (III) to give violet and blood-red coulured complexes in the chloroform layer respectively. The extractability of these acids towards chromium (VI), molybdenum (VI), iron (III), vanadium (V), copper (II) and cobalt (II) was investigated. N-phenyl-N-p-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 96.00% at 1M H{sup 2}SO{sup 4}, molybdenum (VI) 87.00% at pH 1, iron (III) 73.90% at pH 4, vanadium (V) 93.00% at pH 1, cobalt (II) 83.10 at pH 8 and copper (II) 93.80% at pH 6. N-phenyl-N-o-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 97.00% at 1M H{sup 2}SO{sup 4}, molybdenum (VI) 92.70% at pH 1, iron (III) 71.20% at pH 4, vanadium (V) 90.00% at pH 1, cobalt (II) 54.70% at pH 7 and copper (II) 86.50% at pH 5. P-methyl-N-phenyl-N-p-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 98.70% at 1M H{sup 2}SO{sup 4}, molybdenum (VI) 74.00% at pH 1, iron (III) 69.60% at pH 5, vandium (V) 76.00% at pH 1, cobalt (II) 51.20% at pH 8 and copper (II) 82.20% at pH 5. P-methyl-N-phenyl-N-o-bromobenzohydroxamic acid has a maximum extraction for chromium (VI) 51.00% at 1M H{sup 2}SO{sup 4}, molybdenum (VI) 84.70% at pH 1, iron (III) 66.00% at pH 4, vandium (V) 88.00% at pH 1, cobalt (II) 50.00% at pH 7 and copper (II) 78.6% at pH 6. Twenty four of hydroxamic acids complexes of Cr (VI), Mo (VI), V (V), Fe (III), Co (II) and Cu (II) were prepared by the

Synthesis, characterization and corrosion inhibition properties of benzamide-2-chloro-4-nitrobenzoic acid and anthranilic acid-2-chloro-4-nitrobenzoic acid for mild steel corrosion in acidic medium

Science.gov (United States)

Pandey, Archana; Verma, Chandrabhan; Singh, B.; Ebenso, Eno E.

2018-03-01

The present study deals with the synthesis of two new compounds namely, benzamide - 2-chloro-4-nitrobenzoic acid (BENCNBA) and anthranilic acid-2-chloro-4-nitrobenzoic acid (AACNBA) using solid phase reactions. The phase diagram studies revealed that formation of the investigated compounds occurs in 1:1 molar ratio. The synthesized compounds were characterized using several spectral techniques such as FT-IR, 1H and 13C NMR, UV-Vis, powder X-ray diffraction (PXRD). Single crystal XRD (SCXRD) study showed that both BENCNBA and AACNBA compounds crystallize in triclinic crystal system with P-1 space group. Further, the presence of intermolecular hydrogen bonding between the constituent components was also supported by single crystal X-ray diffraction (SCXRD) method. Heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions have also been computed using the enthalpy of fusion values derived from differential scanning calorimeter (DSC) study. The inhibition effect of BENCNBA and AACNBA on the mild steel corrosion in hydrochloric acid solution was tested using electrochemical methods. Electrochemical impedance spectroscopy (EIS) study revealed that both BENCNBA and AACNBA behaved as interface corrosion inhibitors and showed maximum inhibition efficiencies of 95.71% and 96.42%, respectively at 400 ppm (1.23 × 10-3 M) concentration. Potentiodynamic polarization (PDP) measurements suggested that BENCNBA and AACNBA acted as mixed type corrosion inhibitors. EIS and PDP results showed that BENCNBA and AACNBA act as efficient corrosion inhibitors for mild steel and their inhibition efficiencies enhances on increasing their concentrations.

Complexes of heavy lanthanides with o-aminobenzoic acid

International Nuclear Information System (INIS)

Brzyska, W.; Rzaczynska, Z.

1988-01-01

Anthranilates of Tb-Lu prepared in the reaction of the rare earth hydroxides with ortho-aminobenzoic acid (anthranilic acid) have the general formula Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O where Ln = Tb, Dy, Ho, Er, Tm, Yb, Lu. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 493 K dehydration occurs and the anhydrous anthranilates Ln(C 6 H 4 NH 2 COO) 3 are formed. On the basis of the IR spectra it was found that the metal in dihydrated anthranilates was simultaneously coordinated through amino and carboxyl groups whereas in anhydrous anthranilates only through the bidentate carboxyl group. From X-ray analysis it was stated that the anthranilates Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O are isostructural, whereas the anhydrous compounds Ln(C 6 H 4 NH 2 COO) 3 are isostructural in the two groups Tb-Er and Tm-Lu. (Author)

Thermometric titration of beta-aryl-alpha-mercaptopropenoic acids and determination of the stoichiometry of their metal complexes.

Science.gov (United States)

Izquierdo, A; Carrasco, J

1981-05-01

Automatic thermometric titration was applied to some beta-aryl-alpha-mercaptopropenoic acids and the stoichiometry of their complexes with several metal ions was investigated. The heats of neutralization of the mercapto-acids with sodium hydroxide and the heats of their reaction with metal ions were calculated.

Perfluoroalkylation of Aryl-N,N-dimethyl Hydrazones Using Hypervalent Iodine(III) Reagents or Perfluoroalkyl Iodides.

Science.gov (United States)

Janhsen, Benjamin; Studer, Armido

2017-11-17

Radical trifluoromethylation of aryl N,N-dimethyl hydrazones using TBAI as an initiator and Togni's reagent as a trifluoromethyl radical source is described. Cascades proceed via electron-catalysis; this approach is generally more applicable to hydrazone perfluoroalkylation using perfluoroalkyl iodides as the radical precursors in combination with a base under visible-light initiation.

Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and β-cyclodextrin

Science.gov (United States)

Rajendiran, N.; Balasubramanian, T.

2007-11-01

Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and β-cyclodextrin (β-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with β-CD is analysed by UV-vis, fluorimetry, FT-IR, 1H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with β-CD and COOH group present in the β-CD cavity. A mechanism is proposed to explain the inclusion process.

Dual fluorescence of N-phenylanthranilic acid: Effect of solvents, pH and beta-cyclodextrin.

Science.gov (United States)

Rajendiran, N; Balasubramanian, T

2007-11-01

Spectral characteristics of N-phenylanthranilic acid (NPAA) have been studied in different solvents, pH and beta-cyclodextrin (beta-CD) and compared with anthranilic acid (2-aminobenzoic acid, 2ABA). In all solvents a dual fluorescence is observed in NPAA, whereas 2ABA gives single emission. Combining the results observed in the absorption, fluorescence emission and fluorescence excitation spectra, it is found that strong intramolecular hydrogen bonding (IHB) interactions present in NPAA molecule. The inclusion complex of NPAA with beta-CD is analysed by UV-vis, fluorimetry, FT-IR, (1)H NMR, scanning electron microscope and AM 1 method. The above spectral studies show that NPAA forms a 1:1 inclusion complex with beta-CD and COOH group present in the beta-CD cavity. A mechanism is proposed to explain the inclusion process.

LIF excitation spectra for S 0 → S 1 transition of deuterated anthranilic acid COOD, ND 2 in supersonic-jet expansion

Science.gov (United States)

Kolek, Przemysław; Leśniewski, Sebastian; Andrzejak, Marcin; Góra, Maciej; Cias, Pawel; Weģrzynowicz, Adam; Najbar, Jan

2010-12-01

Laser induced fluorescence (LIF) excitation spectrum for the S 0 → S 1 transition of anthranilic acid molecules deuterated in the substituent groups (COOD, ND 2) was investigated. Analysis of the LIF spectrum allowed for the assignment of the six most prominent fundamental in-plane modes of frequencies up to ca. 850 cm. The experimental results show good correlation with the frequency changes upon deuteration computed with CIS (CI-Singles) and TD-DFT for the S 1 state. Deuteration induced red-shifts of the identified fundamental bands are used for examination of the alternative assignments proposed in earlier studies. Potential energy distributions (PED) and overlaps of the in-plane normal modes with frequencies below 850 cm indicate that the correspondence of the respective vibrations of the deuterated and non-deuterated molecule is very good. A blue-shift of the 00 transition due to the isotopic substitution, is equal to 47 cm. This relatively large value is caused primarily by a significant decrease of the N-H stretching frequency associated with the increase of strength of the intramolecular hydrogen bond upon the electronic excitation. The deuteration shift of the 00 band was interpreted in terms of the differences of the zero point energy (ZPE) between the S 0 and S 1 electronic states, computed with DFT and TD-DFT methods, respectively.

Ion-tagged π-acidic alkene ligands promote Pd-catalysed allyl-aryl couplings in an ionic liquid

NARCIS (Netherlands)

Bäuerlein, P.S.; Fairlamb, I.J.S.; Jarvis, A.G.; Lee, A.F.; Müller, C.; Slattery, J.M.; Thatcher, R.J.; Vogt, D.; Whitwood, A.C.

2009-01-01

Ionic p-acidic alkene ligands based on chalcone and benzylidene acetone frameworks have been ?doped? into ionic liquids to provide functional reaction media for Pd-catalysed cross-couplings of a cyclohexenyl carbonate with aryl siloxanes that allow simple product isolation, free from Pd (

Asymmetric synthesis of α-amino acids by reduction of N-tert-butanesulfinyl ketimine esters.

Science.gov (United States)

Reddy, Leleti Rajender; Gupta, Aditya P; Liu, Yugang

2011-05-06

A highly regio- and diastereoselective reduction of various N-tert-butanesulfinyl ketimine esters with L-Selectride resulting in the formation of α-amino acids is reported. This method is quite general and also practical for the preparation of both enantiomers of aryl or aliphatic α-amino acids in high yields. © 2011 American Chemical Society

Reduction of Nitroarenes into Aryl Amines and N-Aryl hydroxylamines via Activation of NaBH4 and Ammonia-Borane Complexes by Ag/TiO2 Catalyst

Directory of Open Access Journals (Sweden)

Dimitrios Andreou

2016-03-01

Full Text Available In this study, we report the fabrication of mesoporous assemblies of silver and TiO2 nanoparticles (Ag/MTA and demonstrate their catalytic efficiency for the selective reduction of nitroarenes. The Ag/TiO2 assemblies, which show large surface areas (119–128 m2·g−1 and narrow-sized mesopores (ca. 7.1–7.4 nm, perform as highly active catalysts for the reduction of nitroarenes, giving the corresponding aryl amines and N-aryl hydroxylamines with NaBH4 and ammonia-borane (NH3BH3, respectively, in moderate to high yields, even in large scale reactions (up to 5 mmol. Kinetic studies indicate that nitroarenes substituted with electron-withdrawing groups reduced faster than those with electron-donating groups. The measured positive ρ values from the formal Hammett-type kinetic analysis of X-substituted nitroarenes are consistent with the proposed mechanism that include the formation of possible [Ag]-H hybrid species, which are responsible for the reduction process. Because of the high observed chemo selectivities and the clean reaction processes, the present catalytic systems, i.e., Ag/MTA-NaBH4 and Ag/MTA-NH3BH3, show promise for the efficient synthesis of aryl amines and N-aryl hydroxylamines at industrial levels.

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels

Directory of Open Access Journals (Sweden)

Boopathy Rathanam

2000-12-01

Full Text Available Abstract Background In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. Results The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. Conclusions A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Indole-3-butyric acid promotes adventitious rooting in Arabidopsis thaliana thin cell layers by conversion into indole-3-acetic acid and stimulation of anthranilate synthase activity.

Science.gov (United States)

Fattorini, L; Veloccia, A; Della Rovere, F; D'Angeli, S; Falasca, G; Altamura, M M

2017-07-11

Indole-3-acetic acid (IAA), and its precursor indole-3-butyric acid (IBA), control adventitious root (AR) formation in planta. Adventitious roots are also crucial for propagation via cuttings. However, IBA role(s) is/are still far to be elucidated. In Arabidopsis thaliana stem cuttings, 10 μM IBA is more AR-inductive than 10 μM IAA, and, in thin cell layers (TCLs), IBA induces ARs when combined with 0.1 μM kinetin (Kin). It is unknown whether arabidopsis TCLs produce ARs under IBA alone (10 μM) or IAA alone (10 μM), and whether they contain endogenous IAA/IBA at culture onset, possibly interfering with the exogenous IBA/IAA input. Moreover, it is unknown whether an IBA-to-IAA conversion is active in TCLs, and positively affects AR formation, possibly through the activity of the nitric oxide (NO) deriving from the conversion process. Revealed undetectable levels of both auxins at culture onset, showing that arabidopsis TCLs were optimal for investigating AR-formation under the total control of exogenous auxins. The AR-response of TCLs from various ecotypes, transgenic lines and knockout mutants was analyzed under different treatments. It was shown that ARs are better induced by IBA than IAA and IBA + Kin. IBA induced IAA-efflux (PIN1) and IAA-influx (AUX1/LAX3) genes, IAA-influx carriers activities, and expression of ANTHRANILATE SYNTHASE -alpha1 (ASA1), a gene involved in IAA-biosynthesis. ASA1 and ANTHRANILATE SYNTHASE -beta1 (ASB1), the other subunit of the same enzyme, positively affected AR-formation in the presence of exogenous IBA, because the AR-response in the TCLs of their mutant wei2wei7 was highly reduced. The AR-response of IBA-treated TCLs from ech2ibr10 mutant, blocked into IBA-to-IAA-conversion, was also strongly reduced. Nitric oxide, an IAA downstream signal and a by-product of IBA-to-IAA conversion, was early detected in IAA- and IBA-treated TCLs, but at higher levels in the latter explants. Altogether, results showed that IBA induced

Design and stereoselective synthesis of a C-aryl furanoside as a conformationally constrained CHIR-090 analogue

DEFF Research Database (Denmark)

Oddo, Alberto; Holl, Ralph

2012-01-01

The UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine deacetylase (LpxC) is a promising target for the development of novel antibiotic substances against multidrug-resistant Gram-negative bacteria. The C-aryl glycoside 3 was designed as conformationally constrained analogue of the potent LpxC-......, and esterification. A Sonogashira reaction of the aryl iodide 11 led to the alkyne 17 which was transformed with H(2)NOH into the hydroxamic acid 3....

Pd-Catalyzed N-Arylation of Secondary Acyclic Amides: Catalyst Development, Scope, and Computational Study

Science.gov (United States)

Hicks, Jacqueline D.; Hyde, Alan M.; Cuezva, Alberto Martinez; Buchwald, Stephen L.

2009-01-01

We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the “top ring” ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate. PMID:19886610

Electronic states of aryl radical functionalized graphenes: Density functional theory study

Science.gov (United States)

Tachikawa, Hiroto; Kawabata, Hiroshi

2016-06-01

Functionalized graphenes are known as a high-performance molecular device. In the present study, the structures and electronic states of the aryl radical functionalized graphene have been investigated by the density functional theory (DFT) method to elucidate the effects of functionalization on the electronic states of graphene (GR). Also, the mechanism of aryl radical reaction with GR was investigated. The benzene, biphenyl, p-terphenyl, and p-quaterphenyl radicals [denoted by (Bz) n (n = 1-4), where n means numbers of benzene rings in aryl radical] were examined as aryl radicals. The DFT calculation of GR-(Bz) n (n = 1-4) showed that the aryl radical binds to the carbon atom of GR, and a C-C single bond was formed. The binding energies of aryl radicals to GR were calculated to be ca. 6.0 kcal mol-1 at the CAM-B3LYP/6-311G(d,p) level. It was found that the activation barrier exists in the aryl radical addition: the barrier heights were calculated to be 10.0 kcal mol-1. The electronic states of GR-(Bz) n were examined on the basis of theoretical results.

Towards a fragment-based approach in gelator design: halogen effects leading to thixotropic, mouldable and self-healing systems in aryl-triazolyl amino acid-based gelators!

Science.gov (United States)

Srivastava, Bhartendu K; Manheri, Muraleedharan K

2017-04-18

A simple replacement of a H atom by Br transformed non-gelating aryl triazolyl amino acid benzyl ester into a versatile gelator, which formed shape-persistent, self-healing and mouldable gels. The 'bromo-aryl benzyl ester' fragment was then transplanted into another framework, which resulted in similar solvent preference and gelation efficiency.

Metal-Free N-Arylation of Secondary Amides at Room Temperature

OpenAIRE

Tinnis, Fredrik; Stridfeldt, Elin; Lundberg, Helena; Adolfsson, Hans; Olofsson, Berit

2015-01-01

The arylation of secondary acyclic amides has been achieved with diaryliodonium salts under mild and metal-free conditions. The methodology has a wide scope, allows synthesis of tertiary amides with highly congested aryl moieties, and avoids the regioselectivity problems observed in reactions with (diacetoxyiodo)benzene.

Improved biological processes for the production of aryl sulfates

DEFF Research Database (Denmark)

2017-01-01

The present invention generally relates to the field of biotechnology as it applies to the production of aryl sulfates using recombinant host cells. More particularly, the present invention pertains to recombinant host cells comprising (e.g., expressing) a polypeptide having aryl sulfotransferase...... activity, wherein said recombinant host cells have been modified to have an increased uptake of sulfate compared to identical host cells that does not carry said modification. Further provided are processes for the production of aryl sulfates, such as zosteric acid, employing such recombinant host cells....

Intramolekulare Friedel-Crafts-Acylierung von N-Phthaloyl-substituierten Aryl- und Homophenylalanylchloriden

OpenAIRE

Effenberger, Franz; Steegmüller, Dieter; Null, Volker; Ziegler, Thomas

1988-01-01

Die intramolekulare Acylierung von N-Phthaloyl-geschützten Aryl- und Homophenylalanychloriden 5 mit zweifach molaren Mengen AlCl3 oder katalytischen Mengen FeCl3 führt zu 2-Phthal-imido-l-indanonen 6 bzw. -1-tetralon (6d). Während die Cyclo-acylierung zum Tetralon 6d mit AlCl3 und mit FeCl3 racemisierungsfrei mit sehr guten Ausbeuten abläuft, erfolgt die Bildung des Indanons 6a mit FeCl3 unter Racemisierung. N-Phthaloyl-geschützte α-Aminosäurechloride bilden mit Silber-trifluormethansulf...

Studies on Synthesis and Dyeing Preformance of Acid Dyes Based on 4,7-Dihydroxy-1,10-Phenanthroline-2,9-Dione

Directory of Open Access Journals (Sweden)

B. V. Patel

2008-01-01

Full Text Available Some new azo acid dyes were prepared by coupling various diazotized acid components such as anthranilic acid, sulphanilic acid, laurent acid, peri acid, tobias acid, H-acid, J-acid, gamma acid, sulphotobias acid, 4-aminotoluiene-3-sulphonic acid, 5-sulpho- anthranilic acid, 2-naphthylamine-3,6,8-trisulphonic acid, bronner acid, metanilic acid and cleve acid with 4,7-dihydroxy-1,10-phenanthroline-2,9-dione. The dyes were characterized by elemental, IR and TLC analyses. Their dyeing performance as acid dyes has been assessed on viscose rayon, wool and cotton fibres.

Exploration of ethyl anthranilate-loaded monolithic matrix-type prophylactic polymeric patch

Directory of Open Access Journals (Sweden)

Johirul Islam

2017-10-01

Full Text Available Compromised stability of pharmaceutical formulations loaded with volatiles is a serious problem associated with devices designed to deliver volatile compounds. The present study has been focused to evaluate the stability potential of matrix-type polymeric patches composed of volatile ethyl anthranilate for prophylaxis against vector-borne diseases. Ethyl anthranilate-loaded matrix-type polymeric patches were fabricated by solvent evaporation method on an impermeable backing membrane and attached to temporary release liners. Stability testing of the polymeric patches was performed as per the International Conference on Harmonization (ICH guidelines for 6 months under accelerated conditions. In addition, the quantification of residual solvents was also performed as per the ICH guidelines. After conducting the stability studies for 6 months, the optimized patches showed the best possible results with respect to uniformity of drug content, physical appearance, and other analytical parameters. Furthermore, the amount of residual solvent was found well below the accepted limit. Thus, the present report outlined the analytical parameters to be evaluated to ensure the stability of a certain devices consisting of volatile compounds.

Smiles Rearrangement Based Practical One-pot Synthesis of N-Alkyl/aryl-6-aminoquinolines from 6-Hydroxylquinoline

Energy Technology Data Exchange (ETDEWEB)

Xie, Yongsheng; Vijaykumar, B. V. D.; Jang, Kiwan; Choi, Kyungmin; Shin, Dongsoo [Changwon National Univ., Changwon (Korea, Republic of); Zuo, Hua [Southwest Univ., Chongqing (Korea, Republic of); Yoon, Yongjin [Gyeongsang National Univ., Chinju (Korea, Republic of)

2013-12-15

The C-N coupling protocol reported herein represents a convenient and practical synthesis of N-alkyl/aryl-6-aminoquinolines in a three-step one-pot manner by simple addition of 6-hydroxyquinoline and N-alkyl/aryl-2-chloroacetamides with Cs{sub 2}CO{sub 3} or K{sub 2}CO{sub 3} in DMF at 150 .deg. C via Smiles rearrangement. An electron donating substituent on the nitrogen counterpart would accelerate the rearrangement process to achieve various anilines in good yields. We currently engaged in making a chemical library including multifarious N-substituted-6-aminoquinolines, to be used in the screening for specific AChEI activity. Furthermore, this work extends the scope of preparing different heterocyclic synthons in drug design for various biological activities. Aminoquinolines and their derivatives are important chemical entities that are widely used as pro-drugs and drugs due to their antimicrobial, cytotoxic and anti-malarial activities etc.

Microwave-assisted synthesis of α-aryl malonates: Key intermediates for the

Directory of Open Access Journals (Sweden)

Mohamed A. Ibrahim

2016-11-01

Full Text Available We disclose a new microwave-assisted protocol for the effective α-arylation of diethyl malonate. The coupling of aryl halides with diethyl malonate proceeds smoothly in short reaction time in the presence of a catalytic amount of Cu(OTf2, 2-picolinic acid and Cs2CO3 in toluene using microwave irradiation. The resulting α-aryl malonates are then used as key intermediates for synthesis of variety of heterocyclic compounds, including benzodiazepines, isoquinolines and pyrrolopyridine scaffolds.

Reaction of aryl diazonium tetrafluoro borates with allyl methacrylate in the presence of rhodanide-anion

International Nuclear Information System (INIS)

Grishchuk, B.D.; Baranovskij, V.S.; Simchak, R.V.; Tulajdan, G.N.; Gorbovoj, P.M.

2006-01-01

Reaction of aryl diazonium tetrafluoro borates (I) with allyl ester of methacrylic acid in the water-acetone (1:5) medium is studied by means of IR spectroscopy and 1 H NMR. It is established that (I) reacts with aryl methacrylate in the presence of rhodanide-anion and catalytic quantities of copper salts with the formation of allyl esters of 2-thiocyanato-2-methyl-3-aryl propionic acids with the yield of 32-56%. Allyl fragment of biunsaturated compound shows no reaction under the tested conditions [ru

SYNTHESIS AND CHARACTERIZATION OF N, N'-BIS-(3 ...

African Journals Online (AJOL)

user

base complexes derived from Salicylaldehyde and histidine with some divalent transition metal ions. Furthermore, Syed (1993) reported the synthesis, characterization and biological evaluation of some. Schiff base metal complexes derived from Anthranilic acid-sugar and naturally occurring amino acid-sugar. Schiff bases ...

Unprecedentedly mild direct Pd-catalyzed arylation of oxazolo[4,5-b]pyridine

DEFF Research Database (Denmark)

Zhuravlev, Fedor

2006-01-01

Pd-catalyzed C-2 arylation of oxazolo[4,5-b]pyridine proceeds efficiently at 30 degrees C and tolerates a variety of aryl halides, including derivatized amino acids for which no racemization was observed during the reaction. Experimental evidence for facile deprotonation of oxazolo[4,5-b...

Palladium(II-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

Directory of Open Access Journals (Sweden)

Tanveer Mahamadali Shaikh

2013-08-01

Full Text Available A series of general and selective Pd(II-catalyzed Heck reactions were investigated under mild reaction conditions. The first protocol has been developed employing an imidazole-based secondary phosphine oxide (SPO ligated palladium complex (6 as a precatalyst. The catalytic coupling of aryl halides and olefins led to the formation of the corresponding coupled products in excellent yields. A variety of substrates, both electron-rich and electron-poor olefins, were converted smoothly to the targeted products in high yields. Compared with the existing approaches employing SPO–Pd complexes in a Heck reaction, the current strategy features mild reaction conditions and broad substrate scope. Furthermore, we described the coupling of arylboronic acids with olefins, which were catalyzed by Pd(OAc2 and employed N-bromosuccinimide as an additive under ambient conditions. The resulted biaryls have been obtained in moderate to good yields.

Acetic acid-promoted condensation of o-phenylenediamine with aldehydes into 2-aryl-1-(arylmethyl-1H-benzimidazoles under microwave irradiation

Directory of Open Access Journals (Sweden)

DAVOOD AZARIF

2010-09-01

Full Text Available An efficient and simple procedure was developed for the green synthesis of various 2-aryl-1-(arylmethyl-1H-benzimidazoles in high yields by acetic acid-promoted condensation of o-phenylenediamine with aldehydes in air under microwave irradiation and transition metal catalyst-free conditions.

Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids

DEFF Research Database (Denmark)

Kromann, Hasse; Sløk, Frank A; Stensbøl, Tine B

2002-01-01

Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are bot...... antagonists at group I mGluRs. Here we report the synthesis and molecular pharmacology of HIBO analogues 9b-h containing different 4-aryl substituents. All of these compounds possess antagonist activity at group I mGluRs but are inactive at group II and III mGluRs....

Photolytic inhibition and labeling of proteins with aryl diazonium compounds

International Nuclear Information System (INIS)

Tometsko, A.M.; Turula, J.; Comstock, J.

1978-01-01

In the course of preparing aryl azide derivatives for use as photoprobes, we have observed significant light sensitivity in the precursor aryl diazonium compounds. The photosensitive properties of this class of compounds are of interest since they will seek out cationic binding sites in biological targets, and can be employed to inhibit complementary targets at acid pH. The relationship between photolytic change in the structure of diazonium compounds and the corresponding change in function of a biological target are presented. Experiments are described in which the dark and light sensitive properties of a model diazonium compound, diazobenzene sulfonate (DBS), were determined. The ultraviolet spectra were used to evaluate the dark stability and light sensitivity og DBS. Chymotrypsin and trypsin served as functioning targets for further evaluation of the photochemical properties. Both enzymes are stable to the probe in the dark at acid pH. A rapid loss of enzyme activity was observed following flash photolysis of DBS-enzyme solutions. Photolytic incorporation of radioactive DBS into chymotrypsin was observed. Aryl diazonium salts can be employed to probe the availability of complementary sites in biological targets at different acid pH values. (Author)

Studies on Synthesis and Dyeing Preformance of Acid Dyes Based on 4,7-Dihydroxy-3,8-di-α-naphthylazo-1,10-phenanthroline-2,9-Dione

Directory of Open Access Journals (Sweden)

B. V. Patel

2007-01-01

Full Text Available Some new azo acid dyes were prepared by coupling various diazotized acid components such as anthranilic acid, sulphanilic acid, laurentacid, peri acid, tobias acid, H-acid, J-acid, gamma acid, sulphotobias acid,4-aminotoluiene-3-sulphonic acid, 5-sulpho- anthranilic acid, 2-naphthylamine-3,6,8-trisulphonic acid, bronner acid, metanilic acid and cleve acid with 4,7-dihydroxy-3,8-di-α-naphthylazo-1,10-phenanthroline-2,9-dione. The dyes were characterized by elemental, IR and TLC analyses. Their dyeing performance as acid dyes has been assessed on viscose rayon, wool and cotton fibres.

Synthesis of 3-acetyl-N-aryl-4-diethylaminoselenet-2(2H)-imines from 4-diethylamino-3-butyn-2-one and aryl isoselenocyanates

OpenAIRE

Atanassov, Plamen K; Linden, Anthony; Heimgartner, Heinz

2004-01-01

The reaction of aryl isoselenocyanates (1a-d) with 4-diethylamino-3-butyn-2-one (6) in refluxing tetrahydrofuran afforded N-arylselenet-2(2H)-imines (7) in moderate yields. The structure of the stable 4-bromophenyl derivative (7b) has been established by X-Ray crystallography. A stepwise cycloaddition via an intermediate zwitterion (A/A¢) is proposed as the reaction mechanism. In boiling tetrahydrofuran, the selenetimines (7) are in equilibrium with ketenimines (B), which were intercepted by ...

Light-Induced C-H Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides.

Science.gov (United States)

Cantillo, David; Mateos, Carlos; Rincon, Juan A; de Frutos, Oscar; Kappe, C Oliver

2015-09-07

Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pd-Catalyzed Cross-Coupling Reactions of Amides and Aryl Mesylates

Science.gov (United States)

Dooleweerdt, Karin; Fors, Brett P.; Buchwald, Stephen L.

2010-01-01

A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-arylamides in moderate to excellent yields. PMID:20420379

Synthesis of quaternary aryl phosphonium salts: photoredox-mediated phosphine arylation.

Science.gov (United States)

Fearnley, A F; An, J; Jackson, M; Lindovska, P; Denton, R M

2016-04-11

We report a synthesis method for the construction of quaternary aryl phoshonium salts at ambient temperature. The regiospecific reaction involves the coupling of phosphines with aryl radicals derived from diaryliodonium salts under photoredox conditions.

Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers

DEFF Research Database (Denmark)

Ambrogio, I.; Fabrizi, G.; Cacchi, S.

2008-01-01

The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction...... tolerates a variety of functional groups, including ether, amide, alcohol, aldehyde, ketone, ester, cyano, carboxylic acid, and nitro groups. Ortho-substituted arylating agents afforded moderate yields in some cases, though good to high yields were obtained with o-iodotoluene, iodovanillin, and 1...

Sulfonamidation of Aryl and Heteroaryl Halides through Photosensitized Nickel Catalysis.

Science.gov (United States)

Kim, Taehoon; McCarver, Stefan J; Lee, Chulbom; MacMillan, David W C

2018-03-19

Herein we report a highly efficient method for nickel-catalyzed C-N bond formation between sulfonamides and aryl electrophiles. This technology provides generic access to a broad range of N-aryl and N-heteroaryl sulfonamide motifs, which are widely represented in drug discovery. Initial mechanistic studies suggest an energy-transfer mechanism wherein C-N bond reductive elimination occurs from a triplet excited Ni II complex. Late-stage sulfonamidation in the synthesis of a pharmacologically relevant structure is also demonstrated. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palladium(II)-catalyzed desulfitative synthesis of aryl ketones from sodium arylsulfinates and nitriles: scope, limitations, and mechanistic studies.

Science.gov (United States)

Skillinghaug, Bobo; Sköld, Christian; Rydfjord, Jonas; Svensson, Fredrik; Behrends, Malte; Sävmarker, Jonas; Sjöberg, Per J R; Larhed, Mats

2014-12-19

A fast and efficient protocol for the palladium(II)-catalyzed production of aryl ketones from sodium arylsulfinates and various organic nitriles under controlled microwave irradiation has been developed. The wide scope of the reaction has been demonstrated by combining 14 sodium arylsulfinates and 21 nitriles to give 55 examples of aryl ketones. One additional example illustrated that, through the choice of the nitrile reactant, benzofurans are also accessible. The reaction mechanism was investigated by electrospray ionization mass spectrometry and DFT calculations. The desulfitative synthesis of aryl ketones from nitriles was also compared to the corresponding transformation starting from benzoic acids. Comparison of the energy profiles indicates that the free energy requirement for decarboxylation of 2,6-dimethoxybenzoic acid and especially benzoic acid is higher than the corresponding desulfitative process for generating the key aryl palladium intermediate. The palladium(II) intermediates detected by ESI-MS and the DFT calculations provide a detailed understanding of the catalytic cycle.

Binding of the 9-O-N-aryl/arylalkyl amino carbonyl methyl substituted berberine analogs to tRNA(phe..

Directory of Open Access Journals (Sweden)

Anirban Basu

Full Text Available BACKGROUND: Three new analogs of berberine with aryl/ arylalkyl amino carbonyl methyl substituent at the 9-position of the isoquinoline chromophore along with berberrubine were studied for their binding to tRNA(phe by wide variety of biophysical techniques like spectrophotometry, spectrofluorimetry, circular dichroism, thermal melting, viscosity and isothermal titration calorimetry. METHODOLOGY/ PRINCIPAL FINDINGS: Scatchard binding isotherms revealed that the cooperative binding mode of berberine was propagated in the analogs also. Thermal melting studies showed that all the 9-O-N-aryl/arylalkyl amino carbonyl methyl substituted berberine analogs stabilized the tRNA(phe more in comparison to berberine. Circular dichroism studies showed that these analogs perturbed the structure of tRNA(phe more in comparison to berberine. Ferrocyanide quenching studies and viscosity results proved the intercalative binding mode of these analogs into the helical organization of tRNA(phe. The binding was entropy driven for the analogs in sharp contrast to the enthalpy driven binding of berberine. The introduction of the aryl/arylalkyl amino carbonyl methyl substituent at the 9-position thus switched the enthalpy driven binding of berberine to entropy dominated binding. Salt and temperature dependent calorimetric studies established the involvement of multiple weak noncovalent interactions in the binding process. CONCLUSIONS/ SIGNIFICANCE: The results showed that 9-O-N-aryl/arylalkyl amino carbonyl methyl substituted berberine analogs exhibited almost ten folds higher binding affinity to tRNA(phe compared to berberine whereas the binding of berberrubine was dramatically reduced by about twenty fold in comparison to berberine. The spacer length of the substitution at the 9-position of the isoquinoline chromophore appears to be critical in modulating the binding affinities towards tRNA(phe.

Metal-free, visible-light-mediated direct C-H arylation of heteroarenes with aryl diazonium salts.

Science.gov (United States)

Hari, Durga Prasad; Schroll, Peter; König, Burkhard

2012-02-15

Visible light along with 1 mol % eosin Y catalyzes the direct C-H bond arylation of heteroarenes with aryl diazonium salts by a photoredox process. We have investigated the scope of the reaction for several aryl diazonium salts and heteroarenes. The general and easy procedure provides a transition-metal-free alternative for the formation of aryl-heteroaryl bonds.

Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

Science.gov (United States)

Lochmeyer, C; Koch, J; Fuchs, G

1992-06-01

The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes.

Synthesis and preliminary evaluation of antinociceptive activity of novel isoxazolyl-aryl-hydrazones

International Nuclear Information System (INIS)

Reis, Silvio Leandro Goncalves Bomfim; Almeida, Valderes Moraes de; Almeida, Gleybson Correia de; Boaviagem, Karinna Moura; Mendes, Charles Christophe du Barriere; Faria, Antonio Rodolfo de; Goes, Alexandre Jose da Silva; Magalhaes, Laudelina Rodrigues; Silva, Teresinha Goncalves da

2011-01-01

New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several phenyl-hydrazines produced new isoxazolyl-aryl-hydrazones, which showed low toxicity and excellent antinociceptive activity, when compared to dipyrone. The antinociceptive activity of isoxazolyl-aryl-hydrazones was performed using the acetic acid-induced mice abdominal constrictions test. (author)

Synthesis of 4-aryl-2,6-dimethyl-3,5-bis-N-(aryl-carbamoyl-1,4-dihydropyridines as novel skin protecting and anti-aging agents

Directory of Open Access Journals (Sweden)

Aamer Saeed

2017-06-01

Full Text Available A series of 4-aryl-2,6-dimethyl-3,5-bis-N-(aryl-carbamoyl-1,4-dihydropyri-dines 6a-6h were prepared by using the one-pot three component synthetic method. The target compounds 6a-6h were synthesized by reacting two molar equivalents of ketone functionality and one mole of aromatic aldehydes in ammonium acetate to obtain the desired products. The structures of newly synthesized compounds were characterized by FT-IR, 1H-NMR, 13C-NMR, and elemental analysis. All the synthesized compounds were screened for their elastase inhibition and antioxidant activity. Almost all of the com-pounds 6a-h showed good to excellent activities against elastase enzyme more than the reference drug. Compounds 6d and 6b at 0.2 ± 0.0 µM and 0.2 ± 0.0 µM were found to most potent derivatives against elastase enzyme. Compound 6a exhibited prominent free radical scavenging activity. From the results of the biological activity, we infer that some derivatives can serve as lead molecules in pharmacology.

Palladium-catalyzed aryl C-H olefination with unactivated, aliphatic alkenes.

Science.gov (United States)

Deb, Arghya; Bag, Sukdev; Kancherla, Rajesh; Maiti, Debabrata

2014-10-01

Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki-Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon-hydrogen (C-H) bonds (Fujiwara-Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C-H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C-H olefination for synthesizing divinylbenzene derivatives.

2-([1,2,4]triazolo[1,5-c]quinazolin-2-yl-alkyl-(alkaryl-, aryl--amines and their derivatives. (3Н-quinazolin-4-ylidenhydrazides (1,3-dioxo-1,3-dihydro-2H-isoindol-2-ylalkyl-(alkaryl-, aryl-carboxylic acids: features of synthesis, modification and ant

Directory of Open Access Journals (Sweden)

Yu. V. Martynenko

2016-08-01

Full Text Available The combination of different «pharmacophore» components in one structure connected via «linker» functional groups is one of the major and justified approaches for the synthesis of new biologically active substances. In this area (3Н-quinazoline-4-ylidenhydrazides (1,3-dioxo-1,3-dihydro-2H-іsoindol-2-yl-alkyl-(aralkyl-, aryl-carboxylic acids are the most interesting compounds. They contain quinazoline and іsoindole fragments united through аlkyl, аlkaryl and аryl groups and furthermore can be used for the synthesis of new heterocycles. Aim: The purpose of this work is to find antimicrobial and antifungal agents among (3H-quinazolin-4-ylidenehydrazides (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl-alkyl-(alkaryl-, aryl-carboxylic acids and their fused derivatives and to establish physical-chemical properties of these compounds and to correlate «structure – activity relationship» for structure optimization. Methods and results. The study of microbiological activity was conducted by disco-diffusion method on Mueller-Hinton agar on the following strains of microorganisms: gram-positive cocci (Staphylococcus aureus ATCC 25923, Enterococcus aeruginosa, E. faecalis ATCC 29212, gram-negative bacteria (Pseudomonas aeruginosa PSS27853, Escherichia coli ATCC 25922, facultative anaerobic gram-negative bacteria (Klebsiella pneumoniaе and fungi (Candida albicans ATCC 885653. Conclusion. The protected aminoacids were used to synthesize unknown (3H-quinazolin-4-ylidenehydrazides (1,3-dioxo-1,3-dihydroisoindolo-2-yl-alkyl-(alkaryl-, aryl-carboxylic acids in the reactions of nucleophilic substitution for the first time. While new [1,2,4]triazolo[1,5-c]quinazolin-2-yl-alkyl-(alkaryl-, aryl-- isoindol-1,3(2H-diones were received by heterocyclization of the last. Structure and identity have been confirmed by elemental analysis, physical and chemical methods (1H NMR spectroscopy, mass-spectrometry. Analysis of the results of microbiological study shows, that

Well-Defined Copper(I) Fluoroalkoxide Complexes for Trifluoroethoxylation of Aryl and Heteroaryl Bromides

KAUST Repository

Huang, Ronglu

2015-03-17

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Copper(I) fluoroalkoxide complexes bearing dinitrogen ligands were synthesized and the structure and reactivity of the complexes toward trifluoroethoxylation, pentafluoropropoxylation, and tetrafluoropropoxylation of aryl and heteroaryl bromides were investigated. Efficiency drive: A series of copper(I) fluoroalkoxide complexes bearing N,N ligands have been prepared and structurally characterized. These well-defined complexes serve as efficient reagents for the fluoroalkoxylation of aryl and heteroaryl bromides to produce a wide range of trifluoroethyl, pentafluoropropyl, and tetrafluoropropyl (hetero)aryl ethers in good to excellent yields.

Camphor-10-sulfonic acid catalyzed condensation of 2-naphthol with aromatic/aliphatic aldehydes to 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes

Directory of Open Access Journals (Sweden)

Kundu Kshama

2014-01-01

Full Text Available (±-Camphor-10-sulfonic acid (CSA catalyzed condensation of 2-naphthol with both aliphatic/aromatic aldehydes at 80°C yielded 14-alkyl/aryl-dibenzoxanthenes as the sole product in high yields. However, the same condensation with benzaldehyde at 25°C afforded a mixture of intermediate 1,1-bis-(2-hydroxynaphthylphenylmethane and 14-phenyl-dibenzoxanthene while the condensation with aliphatic aldehydes at 25°C furnished the corresponding 14-alkyl-dibenzoxanthenes as the sole product. Moreover, condensation of 2-naphthol with aromatic/aliphatic aldehydes with low catalyst loading (2 mol% was greatly accelerated under microwave irradiation to afford the corresponding 14-aryl/alkyl-dibenzoxanthenes as the sole product in high yields.

Optimization of Aryl Amides that Extend Survival in Prion-Infected Mice.

Science.gov (United States)

Giles, Kurt; Berry, David B; Condello, Carlo; Dugger, Brittany N; Li, Zhe; Oehler, Abby; Bhardwaj, Sumita; Elepano, Manuel; Guan, Shenheng; Silber, B Michael; Olson, Steven H; Prusiner, Stanley B

2016-09-01

Developing therapeutics for neurodegenerative diseases (NDs) prevalent in the aging population remains a daunting challenge. With the growing understanding that many NDs progress by conformational self-templating of specific proteins, the prototypical prion diseases offer a platform for ND drug discovery. We evaluated high-throughput screening hits with the aryl amide scaffold and explored the structure-activity relationships around three series differing in their N-aryl core: benzoxazole, benzothiazole, and cyano. Potent anti-prion compounds were advanced to pharmacokinetic studies, and the resulting brain-penetrant leads from each series, together with a related N-aryl piperazine lead, were escalated to long-term dosing and efficacy studies. Compounds from each of the four series doubled the survival of mice infected with a mouse-passaged prion strain. Treatment with aryl amides altered prion strain properties, as evidenced by the distinct patterns of neuropathological deposition of prion protein and associated astrocytic gliosis in the brain; however, none of the aryl amide compounds resulted in drug-resistant prion strains, in contrast to previous studies on compounds with the 2-aminothiazole (2-AMT) scaffold. As seen with 2-AMTs and other effective anti-prion compounds reported to date, the novel aryl amides reported here were ineffective in prolonging the survival of transgenic mice infected with human prions. Most encouraging is our discovery that aryl amides show that the development of drug resistance is not an inevitable consequence of efficacious anti-prion therapeutics. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Scope and Limitations of Auxiliary-Assisted, Palladium-Catalyzed Arylation and Alkylation of sp2 and sp3 C-H Bonds

Science.gov (United States)

Nadres, Enrico T.; Santos, Gerson Ivan Franco; Shabashov, Dmitry; Daugulis, Olafs

2013-01-01

The scope of palladium-catalyzed, auxiliary-assisted direct arylation and alkylation of sp2 and sp3 C-H bonds of amine and carboxylic acid derivatives has been investigated. The method employs a palladium acetate catalyst, substrate, aryl, alkyl, benzyl, or allyl halide, and inorganic base in t-amyl alcohol or water solvent at 100-140 °C. Aryl and alkyl iodides as well as benzyl and allyl bromides are competent reagents in this transformation. Picolinic acid auxiliary is used for amine γ-functionalization and 8-aminoquinoline auxiliary is used for carboxylic acid β-functionalization. Some optimization of base, additives, and solvent is required for achieving best results. PMID:24090404

Tandem trifluoromethylthiolation/aryl migration of aryl alkynoates to trifluoromethylthiolated alkenes.

Science.gov (United States)

Li, Huan; Liu, Shuai; Huang, Yangen; Xu, Xiu-Hua; Qing, Feng-Ling

2017-09-12

A trifluoromethylthiolation initiated aryl migration of aryl alkynoates was disclosed. This protocol employs AgSCF 3 as the SCF 3 source and MeCN as both the solvent and the hydrogen source. This provides a new access to trifluoromethylthiolated alkenes from readily available substrates and reagents.

Multimetallic catalysed cross-coupling of aryl bromides with aryl triflates

Science.gov (United States)

Ackerman, Laura K. G.; Lovell, Matthew M.; Weix, Daniel J.

2015-08-01

The advent of transition-metal catalysed strategies for forming new carbon-carbon bonds has revolutionized the field of organic chemistry, enabling the efficient synthesis of ligands, materials, and biologically active molecules. In cases where a single metal fails to promote a selective or efficient transformation, the synergistic cooperation of two distinct catalysts--multimetallic catalysis--can be used instead. Many important reactions rely on multimetallic catalysis, such as the Wacker oxidation of olefins and the Sonogashira coupling of alkynes with aryl halides, but this approach has largely been limited to the use of metals with distinct reactivities, with only one metal catalyst undergoing oxidative addition. Here, we demonstrate that cooperativity between two group 10 metal catalysts--(bipyridine)nickel and (1,3-bis(diphenylphosphino)propane)palladium--enables a general cross-Ullmann reaction (the cross-coupling of two different aryl electrophiles). Our method couples aryl bromides with aryl triflates directly, eliminating the use of arylmetal reagents and avoiding the challenge of differentiating between multiple carbon-hydrogen bonds that is required for direct arylation methods. Selectivity can be achieved without an excess of either substrate and originates from the orthogonal reactivity of the two catalysts and the relative stability of the two arylmetal intermediates. While (1,3-bis(diphenylphosphino)propane)palladium reacts preferentially with aryl triflates to afford a persistent intermediate, (bipyridine)nickel reacts preferentially with aryl bromides to form a transient, reactive intermediate. Although each catalyst forms less than 5 per cent cross-coupled product in isolation, together they are able to achieve a yield of up to 94 per cent. Our results reveal a new method for the synthesis of biaryls, heteroaryls, and dienes, as well as a general mechanism for the selective transfer of ligands between two metal catalysts. We anticipate that this

L-tryptophan synthesis from 14C-anthranilic acid in plants with high and low tryptophan content

International Nuclear Information System (INIS)

Kutacek, M.; Eder, J.; Vackova, K.; Prochazka, S.

1978-01-01

The biosynthesis of L-tryptophan (L-trp) from anthranilic acid- 14 C (AA- 14 C) in undamaged organs of the seedlings of kohlrabi and peas, with high L-trp content and maize plants, with low L-trp content was compared. As for maize the experiments were carried out with normal and opaque-2 phenotypes, both with the seedlings and with the ripening kernels. AA- 14 C is metabolized in the plants to L-trp pool and to glycosyl esters of AA. In maize seedlings L-trp- 14 C is synthesized relatively less than in kohlrabi and in pea. The de novo formation of L-trp- 14 C is stopped earlier in maize than in kohlrabi. The level of free L-trp- 14 C is relatively low in maize in comparison with kohlrabi and peas. In spite of this the formation of L-trp- 14 C from AA- 14 C is sufficient in maize to incorporate L-trp both into the proteins and into a secondary metabolite that is not yet defined. At the period of seedlings the incorporation in maize of L-trp into the proteins is comparable with that in kohlrabi, and it is maximum in pea. Maize, at the stage of germination, thus forms proteins rich in L-trp. The formation of free L-trp is approximately ten times lower in ripening kernels and in the leaves adjacent to the ear and it further decreases in the course of the ripening of the kernels. Although the activity of the biosynthesis of the AA- 14 C→L-trp- 14 C pathway is relatively lower in maize than in kohlrabi and peas, this pathway is most responsible for the differences in the content of L-trp in these plants. Neither amitrol nor histidine affected the biosynthesis of L-trp in kohlrabi; the interaction of the biosynthetic pathways of L-trp and histidine known in microorganisms is thus not important in a higher plant. (author)

Silica sulfuric acid and as an efficient catalyst for the Friedlander quinoline synthesis from simple ketones and ortho - amino aryl ketones under microwave irradiation

International Nuclear Information System (INIS)

Zolfigol, M. A.; Salehi, P.; Shiri, M.; Faal Rastegar, T.; Ghaderi, A.

2008-01-01

The synthesis of quinoline derivatives via Friedlander method from ortho-amino aryl ketones in the presence of a catalytic amount of silica sulfuric acid under solvent-free condition and microwave irradiation was described. A good range of simple ketones such as cyclohexanone and deoxybenzoin were used

General and efficient one-pot synthesis of novel sugar/heterocyclic(aryl) 1,2-diketones from sugar terminal alkynes by Sonogashira/tetra-n- butylammonium permanganate oxidation.

Science.gov (United States)

Zhang, Fuyi; Wu, Xiaopei; Wang, Liming; Liu, Hong; Zhao, Yufen

2015-11-19

A new approach for one-pot synthesis of novel sugar/heterocyclic(aryl) 1,2-diketones has been achieved by the reaction of various sugar terminal alkynes with heterocyclic(aryl) iodides at room temperature. This one-pot protocol includes Sonogashira coupling and mild n-Bu4NMnO4 oxidation reaction. This method is mild, general and efficient. Fifty-six examples have been given and the sugar/heterocyclic(aryl) 1,2-diketones were obtained in 71-94% yields. The sugar terminal alkynes include 9 structurally different sugars in pyranose, furanose, and acyclic form which have various protecting groups, sensitive groups, and sterically bulky substituents. The heterocyclic(aryl) iodides include sterically bulky heterocyclic compounds and iodobenzenes with electron-donating, electron-neutral, and electron-withdrawing substituents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Arylation of Rhodium(II) Azavinyl Carbenes with Boronic Acids

Science.gov (United States)

Selander, Nicklas; Worrell, Brady T.; Chuprakov, Stepan; Velaparthi, Subash; Fokin, Valery V.

2013-01-01

A highly efficient and stereoselective arylation of in situ generated azavinyl carbenes affording 2,2-diaryl enamines at ambient temperatures has been developed. These transition metal carbenes are directly produced from readily available and stable 1-sulfonyl-1,2,3-triazoles in the presence of a rhodium carboxylate catalyst. In several cases, the enamines generated in this reaction can be cyclized into substituted indoles employing copper catalysts. PMID:22913576

Palladium-Catalyzed, N-(2-Aminophenyl)acetamide-Assisted Ortho-Arylation of Substituted Benzamides: Application to the Synthesis of Urolithins B, M6, and M7.

Science.gov (United States)

Reddy, M Damoder; Blanton, Alexandra N; Watkins, E Blake

2017-05-19

Pd-catalyzed, selective, monoarylation of ortho-C-H bonds of various benzamides with aryl/heteroaryl iodides has been realized using N-(2-aminophenyl)acetamide (APA) as a new bidentate directing group for the first time. The reaction was tolerant of a wide range of functional groups, and a variety of biaryl amide derivatives were successfully prepared in good to moderate yield. The utilization of N-(2-aminophenyl)acetamide as a novel directing group, Mn(OAc) 2 as a co-oxidant (silver free reaction conditions), and absolute ortho-monoaryl selectivity are notable features of this reaction. In addition, the obtained monoarylated products could be further transformed into the bioactive natural products and human microflora metabolites of dietary ellagic acid derivatives, urolithin B, urolithin M6, and urolithin M7.

Chain-modified radioiodinated fatty acids

International Nuclear Information System (INIS)

Otto, C.A.

1987-01-01

Several carbon chain manipulations have been studied in terms of their effects on myocardial activity levels and residence time. The manipulations examined included: chain length, chain branching, chain unsaturation, and carbon-iodine bond stabilization. It was found that chain length affects myocardial activity levels for both straight-chain alkyl acids and branched chain alkyl and aryl acids. Similar results have been reported for the straight-chain aryl acids. Generally, the longer chain lengths correlated with higher myocardial activity levels and longer residence times. This behavior is attributed to storage as triglycerides. Branched chain acids are designed to be anti-metabolites but only the aryl β-methyl acids possessed the expected time course of constant or very slowly decreasing activity levels. The alkyl β-methyl acids underwent rapid deiodination - a process apparently independent of β-oxidation. Inhibition of β-oxidation by incorporation of carbon-carbon double and triple bonds was studied. Deiodination of ω-iodo alkyl fatty acids prevented an assessment of suicide inhibition using an unsaturated alkynoic acid. Stabilization of the carbon-iodine bond by attachment of iodine to a vinylic or aryl carbon was studied. The low myocardial values and high blood values observed for an eleven carbon ω-iodo vinylic fatty acid were not encouraging but ω-iodo aryl fatty acids appear to avoid the problems of rapid deiodination. (Auth.)

Palladium-catalysed arylation of sulfonamide stabilised enolates

CSIR Research Space (South Africa)

Zeevaart, JG

2005-03-07

Full Text Available Alpha-Arylation of inethanesulfonamides using palladium catalysis is described. For example, treatment of N-benzyl-Nmethylmethanesulfonamide with catalytic Pd (OAc) (2) in the presence of sodium tert-butoxide, triphenylphosphine and toluene afforded...

Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Tomofumi [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Fukuoka Institute of Health and Environmental Sciences, 39 Mukaizano, Dazaifu-shi, Fukuoka 818-0135 (Japan); Ichinose, Hirofumi [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Wariishi, Hiroyuki, E-mail: hirowari@agr.kyushu-u.ac.jp [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Bio-Architecture Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Innovation Center for Medical Redox Navigation, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

2010-04-09

We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conserved domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD{sup +}-binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.

Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium

International Nuclear Information System (INIS)

Nakamura, Tomofumi; Ichinose, Hirofumi; Wariishi, Hiroyuki

2010-01-01

We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conserved domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD + -binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.

Investigation into ramie whisker reinforced arylated soy protein composites

CSIR Research Space (South Africa)

Kumar, R

2010-03-01

Full Text Available isolate (SPI). Thiodiglycol was used as a plasticizer for the preparation of SW composites. The SW composites were arylated with 2,2-diphenyl-2-hydroxyethanoic acid through the process of “dip-coating” and coded as SW-B. In this paper, the characterization...

Dual C-H functionalization of N-aryl amines: synthesis of polycyclic amines via an oxidative Povarov approach.

Science.gov (United States)

Min, Chang; Sanchawala, Abbas; Seidel, Daniel

2014-05-16

Iminium ions generated in situ via copper(I) bromide catalyzed oxidation of N-aryl amines readily undergo [4 + 2] cycloadditions with a range of dienophiles. This method involves the functionalization of both a C(sp(3))-H and a C(sp(2))-H bond and enables the rapid construction of polycyclic amines under relatively mild conditions.

The photocatalyzed Meerwein arylation: classic reaction of aryl diazonium salts in a new light.

Science.gov (United States)

Hari, Durga Prasad; König, Burkhard

2013-04-26

The use of diazonium salts for aryl radical generation and C-H arylation processes has been known since 1896 when Pschorr first used the reaction for intramolecular cyclizations. Meerwein developed it further in the early 1900s into a general arylation method. However, this reaction could not compete with the transition-metal-mediated formation of C(sp(2))-C(sp(2)) bonds. The replacement of the copper catalyst with iron and titanium compounds improved the situation, but the use of photocatalysis to induce the one-electron reduction and activation of the diazonium salts is even more advantageous. The first photocatalyzed Pschorr cyclization was published in 1984, and just last year a series of papers described applications of photocatalytic Meerwein arylations leading to aryl-alkene coupling products. In this Minireview we summarize the origins of this reaction and its scope and applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of 3,3-disubstituted oxindoles by visible-light-mediated radical reactions of aryl diazonium salts with N-arylacrylamides.

Science.gov (United States)

Fu, Weijun; Xu, Fengjuan; Fu, Yuqin; Zhu, Mei; Yu, Jiaqi; Xu, Chen; Zou, Dapeng

2013-12-06

A mild and efficient visible-light-mediated diarylation of N-arylacrylamides with aryl diazonium salts under mild conditions has been developed. This method provides convenient access to a variety of useful 3,3-disubstituted oxindoles by constructing two C-C bonds in one step.

Synthesis of Secondary Aromatic Amides via Pd-Catalyzed Aminocarbonylation of Aryl Halides Using Carbamoylsilane as an Amide Source.

Science.gov (United States)

Tong, Wenting; Cao, Pei; Liu, Yanhong; Chen, Jianxin

2017-11-03

Using N-methoxymethyl-N-organylcarbamoyl(trimethyl)silanes as secondary amides source, the direct transformation of aryl halides into the corresponding secondary aromatic amides via palladium-catalyzed aminocarbonylation is described. The reactions tolerated a broad range of functional groups on the aryl ring except big steric hindrance of substituent. The types and the relative position of substituents on the aryl ring impact the coupling efficiency.

Pot-Economy Autooxidative Condensation of 2-Aryl-2-lithio-1,3-dithianes.

Science.gov (United States)

Vale, João R; Rimpiläinen, Tatu; Sievänen, Elina; Rissanen, Kari; Afonso, Carlos A M; Candeias, Nuno R

2018-02-16

The autoxidative condensation of 2-aryl-2-lithio-1,3-dithianes is here reported. Treatment of 2-aryl-1,3-dithianes with n-BuLi in the absence of any electrophile leads to condensation of three molecules of 1,3-dithianes and formation of highly functionalized α-thioether ketones orthothioesters in 51-89% yields upon air exposure. The method was further expanded to benzaldehyde dithioacetals, affording corresponding orthothioesters and α-thioether ketones in 48-97% yields. The experimental results combined with density functional theory studies support a mechanism triggered by the autoxidation of 2-aryl-2-lithio-1,3-dithianes to yield a highly reactive thioester that undergoes condensation with two other molecules of 2-aryl-2-lithio-1,3-dithiane.

Synthesis and Biological Activities of Novel Anthranilic Diamides Analogues Containing Benzo[b]thiophene

Institute of Scientific and Technical Information of China (English)

ZHANG Ji-feng; LIU Chen; LIU Peng-fei; YAN Tao; WANG Bao-lei; XIONG Li-xia; LI Zheng-ming

2013-01-01

A series of novel anthranilic diamides analogues containing benzo[b]thiophenyl ring was designed and synthesized.Their structures were characterized by melting points,1H nuclear magnetic resonance(1H NMR) and high-resolution mass spectrometry(HRMS).The bioassay tests indicate that their insecticidal activities were weak to moderate.Antibacterial tests indicate that some of the compounds showed favourable activity in vitro against Physalospora piricola,Alternaria solani,Cercospora arachidicola,Gibberella sanbinetti and Phytophthora infestans at a dosage of 50 mg/L.

Facile Arylation of Four-Coordinate Boron Halides by Borenium Cation Mediated Boro-desilylation and -destannylation.

Science.gov (United States)

Crossley, Daniel L; Cid, Jessica; Curless, Liam D; Turner, Michael L; Ingleson, Michael J

2015-12-28

The addition of AlCl 3 to four-coordinate boranes of the general formula (C-N-chelate)BCl 2 results in halide abstraction and formation of three-coordinate borenium cations of the general formula [(C-N-chelate)BCl] + . The latter react with both arylstannanes and arylsilanes by boro-destannylation and -desilylation, respectively, to form arylated boranes. Catalytic quantities of AlCl 3 were sufficient to effect high-yielding arylation of (C-N-chelate)BCl 2 . Boro-destannylation is more rapid than boro-desilylation and leads to double arylation at the boron center, whereas in reactions with arylsilanes either single or double arylation occurs dependent on the nucleophilicity of the arylsilane and on the electrophilicity of the borenium cation. The electrophilicity of the borenium cation derived from 2-phenylpyridine was greater than that of the benzothiadiazole analogues, enabling the boro-desilyation of less nucleophilic silanes and the direct electrophilic borylation of 2-methylthiophene.

Ligand-Enabled Reactivity and Selectivity in a Synthetically Versatile Aryl C–H Olefination*

Science.gov (United States)

Wang, Dong-Hui; Engle, Keary M.; Shi, Bing-Feng; Yu, Jin-Quan

2010-01-01

The Mizoroki–Heck reaction, which couples aryl halides with olefins, has been widely used to stitch together the carbogenic cores of numerous complex organic molecules. Given that the position-selective introduction of a halide onto an arene is not always straightforward, direct olefination of aryl C–H bonds would obviate the inefficiencies associated with generating halide precursors or their equivalents; however, methods for carrying out such a reaction have suffered from narrow substrate scope and low positional selectivity. Here we report an operationally simple, atom-economical, carboxylate-directed Pd(II)-catalyzed C–H olefination reaction with phenylacetic acid and 3-phenylpropionic acid substrates, using oxygen at atmospheric pressure as the oxidant. The positional selectivity can be tuned by introducing amino acid derivatives as ligands. We demonstrate the versatility of the method through direct elaboration of commercial drug scaffolds and efficient synthesis of 2-tetralone and naphthoic acid natural product cores. PMID:19965380

Synthesis and properties of poly(aryl sulfone benzimidazole) and its copolymers for high temperature membrane electrolytes for fuel cells

DEFF Research Database (Denmark)

Yang, Jingshuai; Li, Qingfeng; Cleemann, Lars Nilausen

2012-01-01

Poly(aryl sulfone benzimidazole) (SO2PBI) and its copolymers with poly[2,2′-p-(phenylene)-5,5′-bibenzimidazole] (pPBI), termed as Co-SO2PBI, were synthesized with varied feeding ratios of 4,4′-sulfonyldibenzoic acid (SDBA) to terephthalic acid (TPA). Incorporation of the stiff para-phenylene and ......Poly(aryl sulfone benzimidazole) (SO2PBI) and its copolymers with poly[2,2′-p-(phenylene)-5,5′-bibenzimidazole] (pPBI), termed as Co-SO2PBI, were synthesized with varied feeding ratios of 4,4′-sulfonyldibenzoic acid (SDBA) to terephthalic acid (TPA). Incorporation of the stiff para...

Synthesis of 3-fluoro-3-aryl oxindoles: Direct enantioselective α arylation of amides

KAUST Repository

Wu, Linglin; Falivene, Laura; Drinkel, Emma E.; Grant, Sharday; Linden, Anthony; Cavallo, Luigi; Dorta, Reto

2012-01-01

Modus operandi: Catalytic access to the title compounds through a new asymmetric α-arylation protocol is reported (see scheme). These products are formed in good yields and excellent enantioselectivities by using a new and easily synthesized chiral N-heterocyclic carbene (NHC) ligand. Advanced DFT calculations reveal the properties of the NHC ligand and the mode of operation of the catalyst. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of 3-fluoro-3-aryl oxindoles: Direct enantioselective α arylation of amides

KAUST Repository

Wu, Linglin

2012-02-06

Modus operandi: Catalytic access to the title compounds through a new asymmetric α-arylation protocol is reported (see scheme). These products are formed in good yields and excellent enantioselectivities by using a new and easily synthesized chiral N-heterocyclic carbene (NHC) ligand. Advanced DFT calculations reveal the properties of the NHC ligand and the mode of operation of the catalyst. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly Efficient Synthesis of 2-Aryl-3-methoxyacrylates via Suzuki-Miyaura Coupling Reaction

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyung Ho; Lee, Chun Ho; Song, Young Seob; Park, No Kyun; Kim, Bum Tae; Heo, Jung Nyoung [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)

2006-02-15

We have developed a highly efficient and convergent synthesis of 2-aryl-3-methoxyacrylates via the Suzuki-Miyaura coupling reaction of α-iodo-β-methoxy-acrylate with arylboronic acids. The biological activities of 2-aryl-3-methoxyacrylate derivatives will be reported in due course. The Suzuki-Miyaura coupling reaction provides a convenient access to the carbon-carbon bond formation with high efficiency. Recently, a number of 2-aryl-3-methoxy-acrylates served as a key scaffold for the development of biologically active pharmaceuticals and agrochemicals. Especially, the discovery of the naturally-occurring fungicides, such as strobilurin A and oudemansin A, possessing a β-methoxyacrylate moiety was immediately seized great attention by industrial research groups to open a new era of the strobilurin family including azoxy-strobin and picoxystrobin.

Palladium(II)-catalyzed ortho-C-H arylation/alkylation of N-benzoyl α-amino ester derivatives.

Science.gov (United States)

Misal Castro, Luis C; Chatani, Naoto

2014-04-14

The palladium-catalyzed arylation/alkylation of ortho-C-H bonds in N-benzoyl α-amino ester derivatives is described. In such a system both the NH-amido and the CO2R groups in the α-amino ester moieties play a role in successful C-H activation/C-C bond formation using iodoaryl coupling partners. A wide variety of functional groups and electron-rich/deficient iodoarenes are tolerated. The yields obtained range from 20 to 95%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoinduced C-C Cross-Coupling of Aryl Chlorides and Inert Arenes

Directory of Open Access Journals (Sweden)

Lele Wang

2016-01-01

Full Text Available Here we report a facile, efficient, and catalyst-free method to realize C-C cross-coupling of aryl chlorides and inert arenes under UV light irradiation. The aryl radical upon homolytic cleavage of C-Cl bond initiated the nucleophilic substitution reaction with inert arenes to give biaryl products. This mild reaction mode can also be applied to other synthetic reactions, such as the construction of C-N bonds and trifluoromethylated compounds.

Transition Metal Free C-N Bond Forming Dearomatizations and Aryl C-H Aminations by in Situ Release of a Hydroxylamine-Based Aminating Agent.

Science.gov (United States)

Farndon, Joshua J; Ma, Xiaofeng; Bower, John F

2017-10-11

We outline a simple protocol that accesses directly unprotected secondary amines by intramolecular C-N bond forming dearomatization or aryl C-H amination. The method is dependent on the generation of a potent electrophilic aminating agent released by in situ deprotection of O-Ts activated N-Boc hydroxylamines.

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion

Directory of Open Access Journals (Sweden)

Ana Chira

2017-02-01

Full Text Available Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctylaniline, 4-aminoantipyrine, 4-(4-aminophenylbutyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM. The electrodeposited mass varies between 26 ng/cm2 for 4-fluoroaniline formed during 30 s to 442 ng/cm2 for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenylbutyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion.

Science.gov (United States)

Chira, Ana; Bucur, Bogdan; Radu, Gabriel-Lucian

2017-02-28

Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctyl)aniline, 4-aminoantipyrine, 4-(4-aminophenyl)butyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM). The electrodeposited mass varies between 26 ng/cm² for 4-fluoroaniline formed during 30 s to 442 ng/cm² for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN) and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenyl)butyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

A modified approach to 2-(N-aryl)-1,3-oxazoles: application to the synthesis of the IMPDH inhibitor BMS-337197 and analogues.

Science.gov (United States)

Dhar, T G Murali; Guo, Junqing; Shen, Zhongqi; Pitts, William J; Gu, Henry H; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Iwanowicz, Edwin J

2002-06-13

[structure: see text] A modified approach to the synthesis of 2-(N-aryl)-1,3-oxazoles, employing an optimized iminophosphorane/heterocumulene-mediated methodology, and its application to the synthesis of BMS-337197, a potent inhibitor of IMPDH, are described.

An air-stable copper reagent for nucleophilic trifluoromethylthiolation of aryl halides

KAUST Repository

Weng, Zhiqiang

2012-12-12

A series of copper(I) trifluoromethyl thiolate complexes have been synthesized from the reaction of CuF2 with Me3SiCF 3 and S8 (see scheme; Cu red, F green, N blue, S yellow). These air-stable complexes serve as reagents for the efficient conversion of a wide range of aryl halides into the corresponding aryl trifluoromethyl thioethers in excellent yields. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An air-stable copper reagent for nucleophilic trifluoromethylthiolation of aryl halides

KAUST Repository

Weng, Zhiqiang; He, Weiming; Chen, Chaohuang; Lee, Richmond; Tan, Davin; Lai, Zhiping; Kong, Dedao; Yuan, Yaofeng; Huang, Kuo-Wei

2012-01-01

A series of copper(I) trifluoromethyl thiolate complexes have been synthesized from the reaction of CuF2 with Me3SiCF 3 and S8 (see scheme; Cu red, F green, N blue, S yellow). These air-stable complexes serve as reagents for the efficient conversion of a wide range of aryl halides into the corresponding aryl trifluoromethyl thioethers in excellent yields. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aryl-derivatized, water-soluble functionalized carbon nanotubes for biomedical applications

International Nuclear Information System (INIS)

Karousis, N.; Ali-Boucetta, H.; Kostarelos, K.; Tagmatarchis, N.

2008-01-01

The functionalization of very-thin multi-walled carbon nanotubes (VT-MWNTs) with an aniline derivative, via the protocol of in situ generated aryl diazonium salts results, upon acidic deprotection of the terminal BOC group, on the formation of the water-soluble positively charged ammonium functionalized VT-MWNTs-NH 3 + material. The new materials have been structurally and morphologically characterized by infra-red (ATR-IR) spectroscopy and transmission electron microscopy (TEM). The quantitative calculation of the grafted aryl units onto the skeleton of VT-MWNTs has been estimated by thermogravimetric analysis (TGA), while the quantitative Kaiser test showed the amine group loaded onto VT-MWNTs-NH 3 + material. The aqueous solubility of this material has allowed the performance of some initial toxicological in vitro investigations

A Convenient and Efficient Method for Demethylation of Aryl Methyl Ethers with Magnesium Iodide in Ionic Liquid

International Nuclear Information System (INIS)

Lee, Kwan Soo; Kim, Kee D.

2010-01-01

We have developed a new and efficient method for the demethylation of various types of aryl methyl ethers using readily available, stable, and easily handled magnesium iodide in [BMIM]BF 4 ionic liquid. Owing to its simplicity and mild reaction conditions the protocol reported herein may serve as a useful alternative to the existing methods for the deprotection of aryl methyl ethers to the corresponding phenolic derivatives. Demethylation of aryl methyl ethers to the corresponding phenols are very important reactions in organic synthesis. A number of methods have been reported for the cleavage of highly stable aryl methyl ethers utilizing strong acids or bases such as aluminum chloride, boron tribromide, cerium chloride, alkaline thiolate, methyl magnesium iodide, and L-Selectride. However, all of these methods invariably suffered from one or more drawbacks such as harsh reaction conditions, long reaction times, difficulty of manipulation, use of exotic reagents, and low reaction yields. Furthermore, in the most of known methods for demethylation of aryl methyl ethers, use of large excess amounts of demethylating agents have been generally required. Thus, it is highly desirable to develop an improved convenient and efficient procedure for demethylation reactions of aryl methyl ethers

A Convenient and Efficient Method for Demethylation of Aryl Methyl Ethers with Magnesium Iodide in Ionic Liquid

Energy Technology Data Exchange (ETDEWEB)

Lee, Kwan Soo [KAIST, Daejeon (Korea, Republic of); Kim, Kee D. [Sangji University, Wonju (Korea, Republic of)

2010-12-15

We have developed a new and efficient method for the demethylation of various types of aryl methyl ethers using readily available, stable, and easily handled magnesium iodide in [BMIM]BF{sub 4} ionic liquid. Owing to its simplicity and mild reaction conditions the protocol reported herein may serve as a useful alternative to the existing methods for the deprotection of aryl methyl ethers to the corresponding phenolic derivatives. Demethylation of aryl methyl ethers to the corresponding phenols are very important reactions in organic synthesis. A number of methods have been reported for the cleavage of highly stable aryl methyl ethers utilizing strong acids or bases such as aluminum chloride, boron tribromide, cerium chloride, alkaline thiolate, methyl magnesium iodide, and L-Selectride. However, all of these methods invariably suffered from one or more drawbacks such as harsh reaction conditions, long reaction times, difficulty of manipulation, use of exotic reagents, and low reaction yields. Furthermore, in the most of known methods for demethylation of aryl methyl ethers, use of large excess amounts of demethylating agents have been generally required. Thus, it is highly desirable to develop an improved convenient and efficient procedure for demethylation reactions of aryl methyl ethers.

Protection against mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus using a novel insect repellent, ethyl anthranilate.

Science.gov (United States)

Islam, Johirul; Zaman, Kamaruz; Tyagi, Varun; Duarah, Sanjukta; Dhiman, Sunil; Chattopadhyay, Pronobesh

2017-10-01

Growing concern on the application of synthetic mosquito repellents in the recent years has instigated the identification and development of better alternatives to control different mosquito-borne diseases. In view of above, present investigation evaluates the repellent activity of ethyl anthranilate (EA), a non-toxic, FDA approved volatile food additive against three known mosquito vectors namely, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus under laboratory conditions following standard protocols. Three concentration levels (2%, 5% and 10% w/v) of EA were tested against all the three selected mosquito species employing K & D module and arm-in-cage method to determine the effective dose (ED 50 ) and complete protection time (CPT), respectively. The repellent activity of EA was further investigated by modified arm-in-cage method to determine the protection over extended spatial ranges against all mosquito species. All behavioural situations were compared with the well-documented repellent N,N-diethylphenyl acetamide (DEPA) as a positive control. The findings demonstrated that EA exhibited significant repellent activity against all the three mosquitoes species. The ED 50 values of EA, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus were found to be 0.96%, 5.4% and 3.6% w/v, respectively. At the concentration of 10% w/v, it provided CPTs of 60, 60 and 30min, respectively, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes. Again in spatial repellency evaluation, EA was found to be extremely effective in repelling all the three tested species of mosquitoes. Ethyl anthranilate provided comparable results to standard repellent DEPA during the study. Results have concluded that the currently evaluated chemical, EA has potential repellent activity against some well established mosquito vectors. The study emphasizes that repellent activity of EA could be exploited for developing effective, eco

Photooxidative cleavage of 4(1H)-quinolinones to 2-acylaminobenzoic acids and derivatives

Energy Technology Data Exchange (ETDEWEB)

Staskun, B. (University of the Witwatersrand, Johannesburg (South Africa). Dept. of Chemistry); Foote, C.S. (California Univ., Los Angeles (USA). Dept. of Chemistry)

1984-12-01

4(1H)-Quinolinones undergo oxidative cleavage to afford the corresponding 2-acylaminobenzoic acids when subjected to dye-sensitized photooxygenation in methanol-aqueous sodium hydroxide solution. The derived 2-aminobenzoic acid was the predominant product in certain instances. The reaction, with singlet oxygen suggested as the active species, provides an alternative methodology for access to nuclear- substituted anthranilic acids and derivatives.

Increasing human Th17 differentiation through activation of orphan nuclear receptor retinoid acid-related orphan receptor γ (RORγ) by a class of aryl amide compounds.

Science.gov (United States)

Zhang, Wei; Zhang, Jing; Fang, Leiping; Zhou, Ling; Wang, Shuai; Xiang, Zhijun; Li, Yuan; Wisely, Bruce; Zhang, Guifeng; An, Gang; Wang, Yonghui; Leung, Stewart; Zhong, Zhong

2012-10-01

In a screen for small-molecule inhibitors of retinoid acid-related orphan receptor γ (RORγ), we fortuitously discovered that a class of aryl amide compounds behaved as functional activators of the interleukin 17 (IL-17) reporter in Jurkat cells. Three of these compounds were selected for further analysis and found to activate the IL-17 reporter with potencies of ∼0.1 μM measured by EC₅₀. These compounds were shown to directly bind to RORγ by circular dichroism-based thermal stability experiments. Furthermore, they can enhance an in vitro Th17 differentiation process in human primary T cells. As RORγ remains an orphan nuclear receptor, discovery of these aryl amide compounds as functional agonists will now provide pharmacological tools for us to dissect functions of RORγ and facilitate drug discovery efforts for immune-modulating therapies.

Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuwei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Liquan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wu, Guangshun; Ma, Lichun; Zhao, Min [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

2016-01-30

Graphical abstract: - Highlights: • Carbon fibers are functionalized with benzoic acid groups via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 66%. • Tensile strength of the carbon fibers is preserved after grafting reaction. • The treatment in molten urea can improve modification efficiency greatly. • Using molten urea as the reaction medium can avoid pollution from organic solvents. - Abstract: Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17–10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

International Nuclear Information System (INIS)

Wang, Yuwei; Meng, Linghui; Fan, Liquan; Wu, Guangshun; Ma, Lichun; Zhao, Min; Huang, Yudong

2016-01-01

Graphical abstract: - Highlights: • Carbon fibers are functionalized with benzoic acid groups via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 66%. • Tensile strength of the carbon fibers is preserved after grafting reaction. • The treatment in molten urea can improve modification efficiency greatly. • Using molten urea as the reaction medium can avoid pollution from organic solvents. - Abstract: Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17–10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

Efficient and Simple Synthesis of 6-Aryl-1,4-dimethyl-9H-carbazoles

Directory of Open Access Journals (Sweden)

Sylvain Rault

2008-06-01

Full Text Available A synthetic method for the preparation of 6-aryl-1,4-dimethyl-9H-carbazoles involving a palladium catalyzed coupling reaction of 1,4-dimethyl-9H-carbazole-6-boronic acids and (heteroaryl halides is described.

Tannic Acid an Efficient Catalyst for the Synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one Derivatives

Directory of Open Access Journals (Sweden)

Deepak S. Kawade

2015-06-01

Full Text Available Tannic acid explore a highly efficient catalytic activity for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives in excellent yields via cyclocondensation of aromatic aldehyde, β-naphthol and dimedone. Catalyst having advantages such as it is cheap and biodegradable and the protocol avoids the use of expensive catalyst and toxic solvent. We believe that this methodology is an efficient, simple, highly yielding, time saving and environmentally friendly. DOI: http://dx.doi.org/10.17807/orbital.v7i2.683

Camphyl-based α-diimine palladium complexes: highly efficient precatalysts for direct arylation of thiazoles in open-air.

Science.gov (United States)

Chen, Fu-Min; Lu, Dong-Dong; Hu, Li-Qun; Huang, Ju; Liu, Feng-Shou

2017-07-21

Based on the strategy of the development of phosphine-free palladium-catalyzed direct C-H arylation, a series of camphyl-based α-diimine palladium complexes bearing sterically bulky substituents were synthesized and characterized. The palladium complexes were applied for the cross-coupling of thiazole derivatives with aryl bromides. The effect of the sterically bulky substituent on the N-aryl moiety as well as the reaction conditions was screened. Under the optimal protocols, a wide range of aryl bromides can be smoothly coupled with thiazoles in good to excellent yields in the presence of a low palladium loading of 0.2 mol% under open-air conditions.

Electrochemical Grafting of Graphene Nano Platelets with Aryl Diazonium Salts.

Science.gov (United States)

Qiu, Zhipeng; Yu, Jun; Yan, Peng; Wang, Zhijie; Wan, Qijin; Yang, Nianjun

2016-10-26

To vary interfacial properties, electrochemical grafting of graphene nano platelets (GNP) with 3,5-dichlorophenyl diazonium tetrafluoroborate (aryl-Cl) and 4-nitrobenzene diazonium tetrafluoroborate (aryl-NO 2 ) was realized in a potentiodynamic mode. The covalently bonded aryl layers on GNP were characterized using atomic force microscopy and X-ray photoelectron spectroscopy. Electrochemical conversion of aryl-NO 2 into aryl-NH 2 was conducted. The voltammetric and impedance behavior of negatively and positively charged redox probes (Fe(CN) 6 3-/4- and Ru(NH 3 ) 6 2+/3+ ) on three kinds of aryl layers grafted on GNP reveal that their interfacial properties are determined by the charge states of redox probes and reactive terminal groups (-Cl, -NO 2 , -NH 2 ) in aryl layers. On aryl-Cl and aryl-NH 2 garted GNP, selective and sensitive monitoring of positively charged lead ions as well as negatively charged nitrite and sulfite ions was achieved, respectively. Such a grafting procedure is thus a perfect way to design and control interfacial properties of graphene.

Thermal aromatic Claisen rearrangement and Strecker reaction of alkyl(allyl-aryl ethers under green reaction conditions: Efficient and clean preparation of ortho-allyl phenols (naphthols and alkyl(allyloxyarene-based γ-amino nitriles

Directory of Open Access Journals (Sweden)

Kheila N. Silgado-Gómez

2017-11-01

Full Text Available Chemical transformations of 13 diverse allyl(alkyl-aryl ethers, easily prepared using Williamson reaction of different hydroxyarenes and allyl bromide and alkyl (n-butyl, n-octyl bromides, were studied. Thermal aromatic Claisen rearrangement of allyl-aryl ethers to obtain ortho-allyl phenols (naphthols employing propylene carbonate as a nontoxic and biodegradable solvent was described for the first time. The use of this green solvent allowed to enhance notably product yields and reduce significantly the reaction time comparing with the use of 1,2-dichlorobenzene, toxic solvent, which is traditionally employed in this type of Claisen rearrangement. Three-component Strecker reaction of selected alkyl(allyl-aryl ethers with formyl function on aryl fragment and, piperidine and potassium cyanide in the presence of sulfuric acid supported on silica gel (SSA, SiO2-O-SO3H under mild reaction conditions was used in the preparation of new γ-amino nitriles, analogues of alkaloid girgensohnine [2-(4-hydroxyphenyl-2-(piperidin-1-ylacetonitrile], a perspective biological model in the search for new insecticidal agrochemicals against Aedes aegypti. The use of SSA, an inexpensive and reusable solid catalyst, allowed to obtain new series of 2-[4-alkyl(allyloxyphenyl]-2-(piperidin-1-ylacetonitriles in short time at room temperature with good yields.

Structural optimization of N1-aryl-benzimidazoles for the discovery of new non-nucleoside reverse transcriptase inhibitors active against wild-type and mutant HIV-1 strains.

Science.gov (United States)

Monforte, Anna Maria; De Luca, Laura; Buemi, Maria Rosa; Agharbaoui, Fatima E; Pannecouque, Christophe; Ferro, Stefania

2018-02-01

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are recommended components of preferred combination antiretroviral therapies used for the treatment of human immunodeficiency virus (HIV) infection. These regimens are extremely effective in suppressing virus replication. Recently, our research group identified some N 1 -aryl-2-arylthioacetamido-benzimidazoles as a novel class of NNRTIs. In this research work we report the design, the synthesis and the structure-activity relationship studies of new compounds (20-34) in which some structural modifications have been introduced in order to investigate their effects on reverse transcriptase (RT) inhibition and to better define the features needed to increase the antiviral activity. Most of the new compounds proved to be highly effective in inhibiting both RT enzyme at nanomolar concentrations and HIV-1 replication in MT4 cells with minimal cytotoxicity. Among them, the most promising N 1 -aryl-2-arylthioacetamido-benzimidazoles and N 1 -aryl-2-aryloxyacetamido-benzimidazoles were also tested toward a panel of single- and double-mutants strain responsible for resistance to NNRTIs, showing in vitro antiviral activity toward single mutants L100I, K103N, Y181C, Y188L and E138K. The best results were observed for derivatives 29 and 33 active also against the double mutants F227L and V106A. Computational approaches were applied in order to rationalize the potency of the new synthesized inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phase transition and intramolecular hydrogen bonding in nitro derivatives of ortho-hydroxy acetophenones

Science.gov (United States)

Filarowski, A.; Kochel, A.; Koll, A.; Bator, G.; Mukherjee, S.

2006-03-01

The crystal structures of two ortho-hydroxy aryl ketones (5-chloro-3-nitro-2-hydroxyacetophenone, 5-methyl-3-nitro-2-hydroxyacetophenone and the complex 5-chloro-3-nitro-2-hydroxyacetophenone with 2-aminobenzoic acid (anthranilic acid)) were determined by X-ray diffraction. The existence of an intramolecular hydrogen bond of enol character between the hydroxyl and acetyl groups was found by the X-ray method. The enol character was also confirmed by DFT (B3LYP/6-31+G(d,p)) calculations. A phase transition was found at 138 K in 5-chloro-3-nitro-2-hydroxyacetophenone. This phase transition was investigated by differential scanning calorimetry (DSC), dilatometry, and the dielectric method. A study of the nitro-group dynamics in the ortho-hydroxy acetophenones was carried out with DFT (B3LYP/6-31+G(d,p)) calculations.

Preparation of N-1 -naphthyl benzo- and N-phenyl benzo hydroxamic acids and study of their extractability towards Fe (III), Cr (VI) and U (VI)

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Eltoum Elnour [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

1997-12-01

Two aryl hydroxamic acids were prepared; The N-phenyl benzo hydroxamic acid and the N-1- naphthyl benzohydroxamic acid the first one was prepared by the partial reduction of nitrobenzene to the {beta}-phenyl hydroxylamine and coupling the latter with benzyl chloride. The reduction was carried out using ammonium chloride and zinc dust; this pair failed after so many attempts to give the N-1- naphthyl hydroxylamine. So the latter was prepared by using a somewhat milder reducing agent; hydrogen sulphide and ammonia gas in absolute alcohol. The two acids were obtained using the modified procedure of Tandon coupling the hydroxylamine with benzoyl chloride. The two acids were characterized by their melting points, elemental analysis, their I.R functional group frequencies and by their characteristic colour tests with vanadium (VI) and Iron (III). The acids were used for the extraction and spectrophotometric determination for iron (III), Chromium (VI), and Uranium (VI) from different molar solution, PH and from synthetic sea water. The maximum recovery of iron (III) occurred at PH 4 and PH 5 giving 92.25 and 91.25% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 100% at PH 5 with other acid. The maximum recovery of Chromium (VI) occurred at 3MH{sup 2}SO{sup 4} of 97.50% when using N-1-naphthyl benzohydroxamic acid and a maximum of 94.25% at the same molar concentration with N-phenyl benzo hydroxamic acid. The maximum recovery for Uranium (VI) was occurred at PH 7 giving 100% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 85% at PH 7 and PH* with the other acid. The two reagents give sharp colour with both iron (III) and chromium (VI), so trials were carried out to compare the curves obtained with that of the original reagent i.e. Thiocynate and diphenylcarbazide, which give a smaller slope.(Author) 121 refs. , 15 tabs. , 13 figs

Preparation of N-1 -naphthyl benzo- and N-phenyl benzo hydroxamic acids and study of their extractability towards Fe (III), Cr (VI) and U (VI)

International Nuclear Information System (INIS)

Mohamed, Eltoum Elnour

1997-12-01

Two aryl hydroxamic acids were prepared; The N-phenyl benzo hydroxamic acid and the N-1- naphthyl benzohydroxamic acid the first one was prepared by the partial reduction of nitrobenzene to the β-phenyl hydroxylamine and coupling the latter with benzyl chloride. The reduction was carried out using ammonium chloride and zinc dust; this pair failed after so many attempts to give the N-1- naphthyl hydroxylamine. So the latter was prepared by using a somewhat milder reducing agent; hydrogen sulphide and ammonia gas in absolute alcohol. The two acids were obtained using the modified procedure of Tandon coupling the hydroxylamine with benzoyl chloride. The two acids were characterized by their melting points, elemental analysis, their I.R functional group frequencies and by their characteristic colour tests with vanadium (VI) and Iron (III). The acids were used for the extraction and spectrophotometric determination for iron (III), Chromium (VI), and Uranium (VI) from different molar solution, PH and from synthetic sea water. The maximum recovery of iron (III) occurred at PH 4 and PH 5 giving 92.25 and 91.25% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 100% at PH 5 with other acid. The maximum recovery of Chromium (VI) occurred at 3MH 2 SO 4 of 97.50% when using N-1-naphthyl benzohydroxamic acid and a maximum of 94.25% at the same molar concentration with N-phenyl benzo hydroxamic acid. The maximum recovery for Uranium (VI) was occurred at PH 7 giving 100% when using N-1-naphthyl benzo hydroxamic acid and a maximum recovery of 85% at PH 7 and PH* with the other acid. The two reagents give sharp colour with both iron (III) and chromium (VI), so trials were carried out to compare the curves obtained with that of the original reagent i.e. Thiocynate and diphenylcarbazide, which give a smaller slope.(Author)

Biological processes for the production of aryl sulfates

DEFF Research Database (Denmark)

2016-01-01

The present invention generally relates to the field of biotechnology as it applies to the production of aryl sulfates using polypeptides or recombinant cells comprising said polypeptides. More particularly, the present invention pertains to polypeptides having aryl sulfotransferase activity......, recombinant host cells expressing same and processes for the production of aryl sulfates employing these polypeptides or recombinant host cells....

Tetradentate N2O2 Chelated Palladium(II Complexes: Synthesis, Characterization, and Catalytic Activity towards Mizoroki-Heck Reaction of Aryl Bromides

Directory of Open Access Journals (Sweden)

Siti Kamilah Che Soh

2013-01-01

Full Text Available Four air and moisture-stable palladium(II-Schiff base complexes, N,N′-bis(α-methylsalicylidenepropane-1,3-diamine palladium(II (2a, N,N′-bis(4-methyl-α-methylsalicylidenepropane-1,3-diamine palladium(II (2b, N,N′-bis(3,5-di-tert-butylsalicylidenepropane-1,3-diamine palladium(II (2c, and N,N′-bis(4-methoxy-salicylidenepropane-1,3-diamine palladium(II (2d, have been successfully synthesised and characterised by CHN elemental analyses and conventional spectroscopic methods. These complexes were investigated as catalysts in the phosphine-free Mizoroki-Heck cross-coupling reactions of aryl bromides with methyl acrylate.

Recyclable Polymer-Supported Terpyridine–Palladium Complex for the Tandem Aminocarbonylation of Aryl Iodides to Primary Amides in Water Using NaN3 as Ammonia Equivalent

Directory of Open Access Journals (Sweden)

Toshimasa Suzuka

2017-04-01

Full Text Available Primary aromatic amides are valuable compounds, which are generally prepared via Beckmann rearrangement of oximes and the hydration of nitriles in organic solvents. We investigated the environmentally friendly catalytic aminocarbonylation in water. Thus, a novel heterogeneous transition-metal catalyst, a polymer-supported terpyridine–palladium(II complex, was prepared and found to promote azidocarbonylation of aryl iodides with NaN3 and to reduce the generated benzoyl azides in water under CO gas to yield primary aryl amides with high to excellent yield in a one-pot reaction. The catalyst was recovered and reused several times with no loss of catalytic activity.

New pathway for the biodegradation of indole in Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Kamath, A.; Vaidyanathan, C.S. (Indiana Institute of Science, Bangalore (India))

1990-01-01

Indole and its derivatives form a class of toxic recalcitrant environmental pollutants. The growth of Aspergillus niger was inhibited by very low concentrations (0.005 to 0.02%) of indole, even when 125- to 500-fold excess glucose was present in the medium. When 0.02% indole was added, the fungus showed a lag phase for about 30 h and the uptake of glucose was inhibited. Indole was metabolized by a new pathway via indoxyl (3-hydroxyindole), N-formylanthranilic acid, anthranilic acid, 2,3-dihydroxybenzoic acid, and catechol, which was further degraded by an ortho cleavage. The enzymes N-formylanthranilate deformylase, anthranilate hydroxylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were induced by indole as early as after 5 h of growth, and their activities were demonstrated in a cell-free system.

Nano magnetite (Fe3O4, an efficient and robust catalyst for the one-pot synthesis of 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol and 1-(α-amido alkyl-2-naphthol under ultrasound irradiation

Directory of Open Access Journals (Sweden)

Masoud Mokhtary

2017-01-01

Full Text Available The direct three component reaction via condensation of aldehydes, 2-naphthol and piperidine or acetamide to generate 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol and N-((2-hydroxy naphthalene-1-yl(arylmethylacetamide derivatives has been carried out over Fe3O4 magnetic nanoparticle with high efficiency under ultrasound irradiation. These reactions were studied under different conditions. In terms of reaction time and yield, it was found that optimum results were obtained for the synthesis of 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol under solvent free condition and for preparation of N-((2-hydroxynaphthalene-1-yl(arylmethylacetamide in acetic acid under ultrasound irradiation at 80 °C. Clean methodologies, easy workup procedure, and high yields are some advantages of this work.

21 CFR 74.1339 - D&C Red No. 39.

Science.gov (United States)

2010-04-01

.... Anthranilic acid, not more than 0.2 percent. N,N-(β,β′-Dihydroxy-diethyl) aniline, not more than 0.2 percent... germicidal solutions intended for external application only, and subject to the further restriction that the...

Mechanism-based inactivation of benzo[a]pyrene hydroxylase by aryl acetylenes and aryl olefins

International Nuclear Information System (INIS)

Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

1986-01-01

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo[a]pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo[a]pyrene hydroxylase. The mechanism-based loss of benzo[a]pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, 3 H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo[a]pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne

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

International Nuclear Information System (INIS)

Spitsyn, V.I.; Mozgin, S.V.; Felin, M.G.; Subbotina, N.A.; Ajzenberg, M.I.

1984-01-01

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

Mild one-pot Horner-Wadsworth-Emmons olefination and intramolecular N-arylation for the syntheses of indoles, all regio-isomeric azaindoles, and thienopyrroles.

Science.gov (United States)

Choi, Ji Hye; Lim, Hwan Jung

2015-05-14

The syntheses of various N-protected aromatic-ring fused pyrrole-2-carboxylate derivatives have been accomplished using mild one-pot Horner-Wadsworth-Emmons olefination and Cu-catalyzed intramolecular N-arylation reactions. The optimized mild one-pot reaction conditions of various 2-bromo arylcarboxaldehydes with commercially available N-protected phosphonoglycine trimethylesters gave the desired aromatic-ring fused pyrrole-2-carboxylates, such as substituted indole-, all regio-isomeric azaindole-, and thienopyrrole-2-carboxylates, in good to excellent yields. These conditions showed broad substrate compatibility, without the loss of the protecting group.

Carboxyl functionalization of carbon fibers via aryl diazonium reaction in molten urea to enhance interfacial shear strength

Science.gov (United States)

Wang, Yuwei; Meng, Linghui; Fan, Liquan; Wu, Guangshun; Ma, Lichun; Zhao, Min; Huang, Yudong

2016-01-01

Using molten urea as the solvent, carbon fibers were functionalized with carboxylic acid groups via aryl diazonium reaction in 15 min to improve their interfacial bonding with epoxy resin. The surface functionalization was quantified by X-ray photoelectron spectroscopy, which showed that the relative surface coverage of carboxylic acid groups increased from an initial percentage of 3.17-10.41%. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 66%. Meanwhile, the technique did not adopt any pre-oxidation step to produce functional groups prior to grafting and was shown to maintain the tensile strength of the fibers. This methodology provided a rapid, facile and economically viable route to produce covalently functionalized carbon fibers in large quantities with an eco-friendly method.

Purification and H-1 NMR spectroscopic characterization of phase II metabolites of tolfenamic acid

DEFF Research Database (Denmark)

Sidelmann, U. G.; Christiansen, E.; Krogh, L.

1997-01-01

samples obtained on days 7 to 10 from a human volunteer after oral administration of 200 mg of the drug three times per day (steady-state plasma concentration). The metabolites of tolfenamic acid were initially concentrated by preparative solid phase extraction (PSPE) chromatography, thereby removing...... the endogenous polar compounds that are present in the urine. The individual metabolites were purified by preparative high performance liquid chromatography (HPLC) and then identified using H-1 NMR, Both one- and two-dimensional NMR experiments were performed to identify the phase II metabolites of tolfenamic......), and N-(2-methyl-4-hydroxyphenyl)-anthranilic acid (11) were identified. The phase II metabolites (5-11) had not previously been identified in urine from humans administered tolfenamic acid. The phase I metabolites of the glucuronides 7, 8, 10, and 11 were identified here for the first time. An HPLC...

Synthesis of positron labeled photoactive compounds: 18F labeled aryl azides for positron labeling of biochemical molecules

International Nuclear Information System (INIS)

Hashizume, Kazunari; Hashimoto, Naota; Miyake, Yoshihiro

1995-01-01

The authors have prepared various [ 18 F] fluorine labeled aryl azides as a novel photoactive compounds suitable for positron labeling of biochemical molecules. The introduction of fluorine substituents to aryl azides can be expected to have dramatic effects on their nature and reactivity toward photolysis. Positron labeled reagents for labeling proteins or peptides have recently attracted considerable attention due to their wide applicability in biochemistry and positron emission tomography (PET). Various labeled azide compounds are often used in biochemistry for radiolabeling biological molecules by photolysis, but there have been no reports on the preparation or use of fluorine-18 labeled azides. The authors now report a novel synthesis of 18 F-labeled aryl azides which will have wide application in the biochemistry and nuclear medicine as a means for 18 F-fluorine labeling for proteins, peptides, and nucleic acids. 2 tabs

Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

Directory of Open Access Journals (Sweden)

Mohamed Abboud

2012-02-01

Full Text Available Unusual 2,7-diazacarbazoles were prepared in one step from readily available tetra-halogenated 4,4’-bipyridines by using a double N-arylation reaction in the presence of the Pd–XPhos catalyst system. Moderate to good yields were obtained in this site-selective Buchwald–Hartwig double amination. The functionalization of these tricyclic derivatives was performed by using Pd-catalyzed cross-coupling reactions such as the Stille and Suzuki couplings. Two compounds were analyzed by X-ray diffraction and show π–π stacking involving the diazacarbazole moieties and the phenyl rings of functionalized groups.

Synthesis of a 1-Aryl-2,2-chlorosilyl(phosphasilene Coordinated by an N-Heterocyclic Carbene

Directory of Open Access Journals (Sweden)

Andreas Wolfgang Kyri

2016-09-01

Full Text Available Phosphasilenes, P=Si doubly bonded compounds, have received considerable attention due to their unique physical and chemical properties. We report on the synthesis and structure of a chlorophosphasilene coordinated by an N-heterocyclic carbene (NHC, which has the potential of functionalization at the Si–Cl moiety. Treatment of a silylphosphine, ArPH–SiCl2RSi (Ar = bulky aryl group, RSi = Si(SiMe33 with two equivalents of Im-Me4 (1,3,4,5-tetramethylimidazol-2-ylidene afforded the corresponding NHC-coordinated phosphasilene, ArP=SiClRSi(Im-Me4 as a stable compound. Bonding properties of the P=Si bond coordinated to an NHC will be discussed on the basis of theoretical calculations.

Development of Quantitative Structure-Property Relationship Models for Self-Emulsifying Drug Delivery System of 2-Aryl Propionic Acid NSAIDs

Directory of Open Access Journals (Sweden)

Chen-Wen Li

2011-01-01

Full Text Available We developed the quantative structure-property relationships (QSPRs models to correlate the molecular structures of surfactant, cosurfactant, oil, and drug with the solubility of poorly water-soluble 2-aryl propionic acid nonsteroidal anti-inflammatory drugs (2-APA-NSAIDs in self-emulsifying drug delivery systems (SEDDSs. The compositions were encoded with electronic, geometrical, topological, and quantum chemical descriptors. To obtain reliable predictions, we used multiple linear regression (MLR and artificial neural network (ANN methods for model development. The obtained equations were validated using a test set of 42 formulations and showed a great predictive power, and linear models were found to be better than nonlinear ones. The obtained QSPR models would greatly facilitate fast screening for the optimal formulations of SEDDS at the early stage of drug development and minimize experimental effort.

Intramolecular anionic diels-alder reactions of 1-aryl-4-oxahepta-1,6-diyne systems in DMSO.

Science.gov (United States)

Kudoh, Takayuki; Mori, Tomoko; Shirahama, Mitsuhito; Yamada, Masashi; Ishikawa, Teruhiko; Saito, Seiki; Kobayashi, Hisayoshi

2007-04-25

Base-promoted cycloaddition reactions of 1-aryl- or 1-aryl-7-substituted-4-oxahepta-1,6-diyne systems in DMSO have proven to involve an anionic intramolecular Diels-Alder process taking place even at room temperature in spite of the reaction suffering from temporary disruption of aromaticity. Although initially formed alpha-arylallenide anion can be protonated by DMSO, it can be back to the allenide anion probably because of a small acidity difference between alpha-arylallene and DMSO. The alpha-arylallenide anion in combination with the alpha-aryl substituent can constitute an anionic diene structure that undergoes the intramolecular Diels-Alder reaction involving the C(6)-yne part, a very fast process probably because of the increased HOMO-1 level of the anionic diene, as shown by DFT calculations. Diversified substituted naphthalenes, benzofurans, phenanthrenes, and quinolines, including biaryl architectures, are available from 4-oxahepta-1,6-diynes in a highly expeditious way.

Bio-based phenolic-branched-chain fatty acid isomers synthesized from vegetable oils and natural monophenols using modified h+-ferrierite zeolite

Science.gov (United States)

A new group of phenolic branched-chain fatty acids (n-PBC-FA), hybrid molecules of natural monophenols (i.e., thymol, carvacrol and creosote) and mixed fatty acid (i.e., derived from soybean and safflower oils), were efficiently produced through a process known as arylation. The reaction involves a...

Synthesis of avenanthramides using engineered Escherichia coli.

Science.gov (United States)

Lee, Su Jin; Sim, Geun Young; Kang, Hyunook; Yeo, Won Seok; Kim, Bong-Gyu; Ahn, Joong-Hoon

2018-03-22

Hydroxycinnamoyl anthranilates, also known as avenanthramides (avns), are a group of phenolic alkaloids with anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Some avenanthramides (avn A-H and avn K) are conjugates of hydroxycinnamic acids (HC), including p-coumaric acid, caffeic acid, and ferulic acid, and anthranilate derivatives, including anthranilate, 4-hydroxyanthranilate, and 5-hydroxyanthranilate. Avns are primarily found in oat grain, in which they were originally designated as phytoalexins. Knowledge of the avns biosynthesis pathway has now made it possible to synthesize avns through a genetic engineering strategy, which would help to further elucidate their properties and exploit their beneficial biological activities. The aim of the present study was to synthesize natural avns in Escherichia coli to serve as a valuable resource. We synthesized nine avns in E. coli. We first synthesized avn D from glucose in E. coli harboring tyrosine ammonia lyase (TAL), 4-coumarate:coenzyme A ligase (4CL), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and anthranilate synthase (trpEG). A trpD deletion mutant was used to increase the amount of anthranilate in E. coli. After optimizing the incubation temperature and cell density, approximately 317.2 mg/L of avn D was synthesized. Avn E and avn F were then synthesized from avn D, using either E. coli harboring HpaBC and SOMT9 or E. coli harboring HapBC alone, respectively. Avn A and avn G were synthesized by feeding 5-hydroxyanthranilate or 4-hydroxyanthranilate to E. coli harboring TAL, 4CL, and HCBT. Avn B, avn C, avn H, and avn K were synthesized from avn A or avn G, using the same approach employed for the synthesis of avn E and avn F from avn D. Using different HCs, nine avns were synthesized, three of which (avn D, avn E, and avn F) were synthesized from glucose in E. coli. These diverse avns provide a strategy to synthesize both natural and unnatural avns

Antimitotic antitumor agents: synthesis, structure-activity relationships, and biological characterization of N-aryl-N'-(2-chloroethyl)ureas as new selective alkylating agents.

Science.gov (United States)

Mounetou, E; Legault, J; Lacroix, J; C-Gaudreault, R

2001-03-01

A series of N-aryl-N'-(2-chloroethyl)ureas (CEUs) and derivatives were synthesized and evaluated for antiproliferative activity against a wide panel of tumor cell lines. Systematic structure--activity relationship (SAR) studies indicated that: (i) a branched alkyl chain or a halogen at the 4-position of the phenyl ring or a fluorenyl/indanyl group, (ii) an exocyclic urea function, and (iii) a N'-2-chloroethyl moiety were required to ensure significant cytotoxicity. Biological experiments, such as immunofluorescence microscopy, confirmed that these promising compounds alter the cytoskeleton by inducing microtubule depolymerization via selective alkylation of beta-tubulin. Subsequent evaluations demonstrated that potent CEUs were weak alkylators, were non-DNA-damaging agents, and did not interact with the thiol function of either glutathione or glutathione reductase. Therefore, CEUs are part of a new class of antimitotic agents. Finally, among the series of CEUs evaluated, compounds 12, 15, 16, and 27 were selected for further in vivo trials.

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.

C- versus O-Arylation of an Enol-Lactone Using Potassium tert-butoxide

Directory of Open Access Journals (Sweden)

El Moktar Essassi

2003-05-01

Full Text Available Abstract: The use of potassium tert-butoxide as the base in arylation reactions of an enollactone with a series of benzyl halides was explored. Our work demonstrates that the ratio of C-arylation to O-arylation varies with the substitution pattern of the aryl halide.

Asymmetric Transfer Hydrogenation of 1-Aryl-3,4-Dihydroisoquinolines Using a Cp*Ir(TsDPEN) Complex

Czech Academy of Sciences Publication Activity Database

Václavíková Vilhanová, B.; Budinská, Alena; Václavík, Jiří; Matoušek, V.; Kuzma, M.; Červený, L.

2017-01-01

Roč. 2017, č. 34 (2017), s. 5131-5134 ISSN 1434-193X Institutional support: RVO:61388963 Keywords : 1-aryl-3,4-dihydroisoquinolines * asymmetric synthesis * hydrogenation * iridium * phosphoric acid Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 2.834, year: 2016

Amphoteric surfactants containing ?-hydroxy ester group and an amino acid residue

Directory of Open Access Journals (Sweden)

Eissa, A. M. F.

2006-09-01

Full Text Available A series of amphoteric surfactants containing α-hydroxy ester group and an amino acid residue were prepared with the addition of epoxy derivatives (which were prepared from epoxidation of alkyl methacrylate to different types of amino acids (glycine, alanine, valine, isoleucine, phenylalanine, tyrosine, serine, threonine, aspartic and anthranilic acid.The structures of the prepared compounds were confirmed by infrared spectra, proton magnetic resonance spectra, Mass spectra and elementary analysis. Surface tension, Kraft point, foaming power, critical micelle concentration emulsion and Ca++ stabilities were determined. Antimicrobial activity and biodegradability were also screened.Se prepararon una serie de tensioactivos anfóteros conteniendo un grupo alfa hidroxi éster y un residuo de aminoácido por adición de derivados epoxy (obtenidos mediante epoxidación de metacrilato de alquilo a diferentes tipos de aminoácidos (glicina, alanina, valina, isoleucina, fenilalanina, tirosina, serina, treonina y ácidos aspártico y antranílico. Las estructuras de los compuestos preparados se confirmaron por los espectros de infrarrojo, de masa, resonancia magnética nuclear de protones y análisis elemental. Se determinaron la tensión superficial, el punto de Kraft, el poder espumante, la concentración micelar crítica en emulsión y las estabilidades de Ca++. También se estudiaron la actividad antimicrobiana y la biodegradabilidad.

Conversion of Aryl Iodides into Aryliodine(III Dichlorides by an Oxidative Halogenation Strategy Using 30% Aqueous Hydrogen Peroxide in Fluorinated Alcohol

Directory of Open Access Journals (Sweden)

Ajda Podgoršek

2010-04-01

Full Text Available Oxidative chlorination with HCl/H2O2 in 1,1,1-trifluoroethanol was used to transform aryl iodides into aryliodine(III dihalides. In this instance 1,1,1-trifluoroethanol is not only the reaction medium, but is also an activator of hydrogen peroxide for the oxidation of hydrochloric acid to molecular chlorine. Aryliodine(III dichlorides were formed in 72–91% isolated yields in the reaction of aryl iodides with 30% aqueous hydrogen peroxide and hydrochloric acid at ambient temperature. A study of the effect that substituents on the aromatic ring have on the formation and stability of aryliodine(III dichlorides shows that the transformation is easier to achieve in the presence of the electron-donating groups (i.e. methoxy, but in this case the products rapidly decompose under the reported reaction conditions to form chlorinated arenes. The results suggest that oxidation of hydrogen chloride with hydrogen peroxide is the initial reaction step, while direct oxidation of aryl iodide with hydrogen peroxide is less likely to occur.

Methanofullerene-Based Palladium Bis(amino)aryl Complexes and Applications in Lewis Acid Catalysis

NARCIS (Netherlands)

Koten, G. van; Meijer, M.D.; Ronde, N.; Vogt, D.; Klink, G.P.M. van

2001-01-01

Synthetic routes have been developed for the attachment of palladium(II) bis(amino)aryl (NCN or C6H2{CH2NMe2}2-2,6)- complexes to C60. Using diazo and Bingel addition reactions, various methanofullerene NCN-SiMe3 compounds (C60-L-NCN-SiMe3, L = C(Me), C(CO2Et)CO2CH2, and C(Me)C6H4CC) have been

Photoinduced intramolecular substitution reaction of aryl halide with carbonyl oxygen of amide group

CERN Document Server

Park, Y T; Kim, M S; Kwon, J H

2002-01-01

Photoreaction of N-(o-halophenyl)acetamide in basic acetonitrile produces an intramolecular substituted product, 2-methylbenzoxazole in addition to reduced product, acetanilide, whereas photoreaction of N-(o-halobenzyl)acetamide affords a reduced product, N-benzylacetamide only. On the basis of preparative reaction, kinetics, and UV/vis absorption behavior, an electrophilic aromatic substitution of aryl halide with oxygen of its amide bond are proposed.

Photoinduced intramolecular substitution reaction of aryl halide with carbonyl oxygen of amide group

Energy Technology Data Exchange (ETDEWEB)

Park, Yong Tae; Song, Myong Geun; Kim, Moon Sub; Kwon, Jeong Hee [Kyungpook National Univ., Daegu (Korea, Republic of)

2002-09-01

Photoreaction of N-(o-halophenyl)acetamide in basic acetonitrile produces an intramolecular substituted product, 2-methylbenzoxazole in addition to reduced product, acetanilide, whereas photoreaction of N-(o-halobenzyl)acetamide affords a reduced product, N-benzylacetamide only. On the basis of preparative reaction, kinetics, and UV/vis absorption behavior, an electrophilic aromatic substitution of aryl halide with oxygen of its amide bond are proposed.

Photoinduced intramolecular substitution reaction of aryl halide with carbonyl oxygen of amide group

International Nuclear Information System (INIS)

Park, Yong Tae; Song, Myong Geun; Kim, Moon Sub; Kwon, Jeong Hee

2002-01-01

Photoreaction of N-(o-halophenyl)acetamide in basic acetonitrile produces an intramolecular substituted product, 2-methylbenzoxazole in addition to reduced product, acetanilide, whereas photoreaction of N-(o-halobenzyl)acetamide affords a reduced product, N-benzylacetamide only. On the basis of preparative reaction, kinetics, and UV/vis absorption behavior, an electrophilic aromatic substitution of aryl halide with oxygen of its amide bond are proposed

Synthesis and preliminary evaluation of antinociceptive activity of novel isoxazolyl-aryl-hydrazones; Sintese e avaliacao preliminar de atividade antinociceptiva de novas isoxazolil-aril-hidrazonas

Energy Technology Data Exchange (ETDEWEB)

Reis, Silvio Leandro Goncalves Bomfim; Almeida, Valderes Moraes de; Almeida, Gleybson Correia de; Boaviagem, Karinna Moura; Mendes, Charles Christophe du Barriere; Faria, Antonio Rodolfo de, E-mail: rodolfo@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Ciencias Farmaceuticas; Goes, Alexandre Jose da Silva; Magalhaes, Laudelina Rodrigues; Silva, Teresinha Goncalves da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Antibioticos

2011-07-01

New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several phenyl-hydrazines produced new isoxazolyl-aryl-hydrazones, which showed low toxicity and excellent antinociceptive activity, when compared to dipyrone. The antinociceptive activity of isoxazolyl-aryl-hydrazones was performed using the acetic acid-induced mice abdominal constrictions test. (author)

Rhodium Catalyzed Intramolecular C-H Insertion of α-Aryl-α-diazo Ketones

Science.gov (United States)

Taber, Douglass F.; Tian, Weiwei

2011-01-01

Direct diazo transfer proceeds smoothly with α-aryl ketones. The derived α-aryl-α-diazo ketones cyclize efficiently with Rh catalysis to give the corresponding α-aryl cyclopentanones. PMID:17385917

Preparation of catalytically active, covalent α-polylysine-enzyme conjugates via UV/vis-quantifiable bis-aryl hydrazone bond formation.

Science.gov (United States)

Grotzky, Andrea; Manaka, Yuichi; Kojima, Taisuke; Walde, Peter

2011-01-10

Covalent UV/vis-quantifiable bis-aryl hydrazone bond formation was investigated for the preparation of conjugates between α-poly-d-lysine (PDL) and either α-chymotrypsin (α-CT) or horseradish peroxidase (HRP). PDL and the enzymes were first modified via free amino groups with the linking reagents succinimidyl 6-hydrazinonicotinate acetone hydrazone (S-HyNic, at pH 7.6) and succinimidyl 4-formylbenzoate (S-4FB, at pH 7.2), respectively. The modified PDL and enzymes were then conjugated at pH 4.7, whereby polymer chains carrying several enzymes were obtained. Kinetics of the bis-aryl hydrazone bond formation was investigated spectrophotometrically at 354 nm. Retention of the enzymatic activity after conjugate formation was confirmed by using the substrates N-succinimidyl-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide (for α-CT) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, for HRP). Thus, not only a mild and efficient preparation and convenient quantification of a conjugate between the polycationic α-polylysine and enzymes could be shown, but also the complete preservation of the enzymatic activity.

Cu(I)/Diamine-catalyzed Aryl-alkyne Coupling Reactions

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

CuI/ethylene diamine/K2CO3/dioxane is shown to be a useful system for the cross coupling reactions of various aryl iodides and bromides with aryl and alkyl alkynes. Compared to the conventional Sonogashira reactions, the new procedure is free of palladium and phosphines.

C-H Bond Functionalization via Hydride Transfer: Formation of α-Arylated Piperidines and 1,2,3,4-Tetrahydroisoquinolines via Stereoselective Intramolecular Amination of Benzylic C-H Bonds

OpenAIRE

Vadola, Paul A.; Carrera, Ignacio; Sames, Dalibor

2012-01-01

We here report a study of the intramolecular amination of sp3 C-H bonds via the hydride transfer cyclization of N-tosylimines (HT-amination). In this transformation, 5-aryl-aldehydes are subjected to N-toluenesulfonamide in the presence of BF3•OEt2 to effect imine formation and HT-cyclization, leading to 2-aryl-piperidines and 3-aryl-1,2,3,4-tetrahydroisoquinolines in a one-pot procedure. We examined the reactivity of a range of aldehyde substrates as a function of their conformational flexib...

Rhodium(iii)-catalyzed ortho-olefination of aryl phosphonates.

Science.gov (United States)

Chary, Bathoju Chandra; Kim, Sunggak

2013-09-25

Rhodium(iii)-catalyzed C-H olefination of aryl phosphonic esters is reported for the first time. In this mild and efficient process, the phosphonic ester group is utilized successfully as a new directing group. In addition, mono-olefination for aryl phosphonates is observed using a phosphonic diamide directing group.

Insect Ryanodine Receptor: Distinct But Coupled Insecticide Binding Sites for [N-C3H3]Chlorantraniliprole, Flubendiamide, and [3H]Ryanodine

OpenAIRE

Isaacs, André K.; Qi, Suzhen; Sarpong, Richmond; Casida, John E.

2012-01-01

Radiolabeled anthranilic diamide insecticide [N-C3H3]chlorantraniliprole was synthesized at high specific activity and compared with phthalic diamide insecticide flubendiamide and [3H]ryanodine in radioligand binding studies with house fly muscle membranes to provide the first direct evidence with a native insect ryanodine receptor that the major anthranilic and phthalic diamide insecticides bind at different allosterically coupled sites, i.e. there are three distinct Ca2+-release channel tar...

2-([1,2,4]triazolo[1,5-c]quinazolin-2-yl-)alkyl-(alkaryl-, aryl-)-amines and their derivatives. (3Н-quinazolin-4-yliden)hydrazides (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)alkyl-(alkaryl-, aryl-)carboxylic acids: features of synthesis, modification and ant

OpenAIRE

Yu. V. Martynenko; M. S. Kazunin; E. А. Selivanova; S. I. Kovalenko

2016-01-01

The combination of different «pharmacophore» components in one structure connected via «linker» functional groups is one of the major and justified approaches for the synthesis of new biologically active substances. In this area (3Н-quinazoline-4-yliden)hydrazides (1,3-dioxo-1,3-dihydro-2H-іsoindol-2-yl-)alkyl-(aralkyl-, aryl-)carboxylic acids are the most interesting compounds. They contain quinazoline and іsoindole fragments united through аlkyl, аlkaryl and аryl groups and furthermore can ...

Synthesis and Cyclopolymerzation of N-Aryl Di ‎AllylAmins As Antioxidants for Lubricant's Oil

Directory of Open Access Journals (Sweden)

Firyal M. Ali ‎

2017-12-01

Full Text Available In this research many new N-aryl substituted di allylAmins were  synthesized [ A1-A2 ] which were Polymerized by free radically mechanism by using Ammonium per sulfate  as an initiator at 700C .The new hindered   amines   as  cyclo  polymers  were  characterized  by FTIR  and  H-NMR Spectroscopies ,Physical   and   chemical properties were measured  using TGA and DSC to   study   the thermal stability  of   prepared  cyclopolymers  . These   prepared  N-aromatic  substituted di allylamins cyclopolymers [ A3 - A4 ]  were  used  as  antioxidants  for  lubricant  oil  .   which   give    high stability   when  comparing  with standard  antioxidant . The oxidation stability of base  oil with (1% additive  were  examined according to Institute of Petroleum testing method IP280 

Synthesis and Cyclopolymerzation of N-Aryl Di ‎AllylAmins As Antioxidants for Lubricant's Oil

Directory of Open Access Journals (Sweden)

Firyal M. Ali ‎

2017-12-01

Full Text Available In this research many new N-aryl substituted di allylAmins were  synthesized [ A1-A2 ] which were Polymerized by free radically mechanism by using Ammonium per sulfate  as an initiator at 700C .The new hindered   amines   as  cyclo  polymers  were  characterized  by FTIR  and  H-NMR Spectroscopies ,Physical   and   chemical properties were measured  using TGA and DSC to   study   the thermal stability  of   prepared  cyclopolymers  . These   prepared  N-aromatic  substituted di allylamins cyclopolymers [ A3 - A4 ]  were  used  as  antioxidants  for  lubricant  oil  .   which   give    high stability   when  comparing  with standard  antioxidant . The oxidation stability of base  oil with (1% additive  were  examined according to Institute of Petroleum testing method IP280

Discovery of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as potent RORγt inverse agonists.

Science.gov (United States)

Wang, Yonghui; Yang, Ting; Liu, Qian; Ma, Yingli; Yang, Liuqing; Zhou, Ling; Xiang, Zhijun; Cheng, Ziqiang; Lu, Sijie; Orband-Miller, Lisa A; Zhang, Wei; Wu, Qianqian; Zhang, Kathleen; Li, Yi; Xiang, Jia-Ning; Elliott, John D; Leung, Stewart; Ren, Feng; Lin, Xichen

2015-09-01

A novel series of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as RORγt inverse agonists was discovered. Binding mode analysis of a RORγt partial agonist (2c) revealed by co-crystal structure in RORγt LBD suggests that the inverse agonists do not directly interfere with the interaction between H12 and the RORγt LBD. Detailed SAR exploration led to identification of potent RORγt inverse agonists such as 3m with a pIC50 of 8.0. Selected compounds in the series showed reasonable activity in Th17 cell differentiation assay as well as low intrinsic clearance in mouse liver microsomes. Copyright © 2015 Elsevier Ltd. All rights reserved.

DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids

Science.gov (United States)

Essawy, Amr A.; Afifi, Manal A.; Moustafa, H.; El-Medani, S. M.

2014-10-01

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.

ynthesis and Characterization of 1-Aryl-5-hepta-O-acetyl-β-D-maltosyl-2-S-benzyl-2,4-isodithiobiurets

Directory of Open Access Journals (Sweden)

R. D. Ghuge

2012-01-01

Full Text Available The facile synthesis of 1-aryl-5-hepta-o-acetyl-β-D-maltosyl-2-S-benzyl-2,4-isodithiobiurets (IIIa-g has been achieved by the interaction of 1-hepta-O-acetyl-β–D-maltosyl isothiocyanate (I with various1-aryl-S-benzyl isothiocarbamides (IIa-g. All the newly synthesized N-maltosylated compounds characterized by elemental analysis, IR, NMR and Mass spectral studies.

Surface modified MXene Ti_3C_2 multilayers by aryl diazonium salts leading to large-scale delamination

International Nuclear Information System (INIS)

Wang, Hongbing; Zhang, Jianfeng; Wu, Yuping; Huang, Huajie; Li, Gaiye; Zhang, Xin; Wang, Zhuyin

2016-01-01

Highlights: • A novel and simple method to delaminate MXene Ti_3C_2 multilayers. • Surface modification using aryl diazonium salts induced swelling that conversely weakened the bonds between MXene layers. • The grafting of phenylsulfonic acid groups on MXene surfaces resulted in excellent water dispersibility. - Abstract: Herein we report a simple and facile method to delaminate MXene Ti_3C_2 multilayers by the assistance of surface modification using aryl diazonium salts. The basic strategy involved the preparation of layered MAX Ti_3AlC_2 and the exfoliation of Ti_3AlC_2 into Ti_3C_2 multilayers, followed by Na"+ intercalation and surface modification using sulfanilic acid diazonium salts. The resulting chemically grafted Ti_3C_2 flakes were characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the presence of the surface organic species. Ultraviolet-visible spectroscopy revealed that surface-modified MXene Ti_3C_2 sheets disperse well in water and the solutions obey Lambert–Beer’s law. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to demonstrate the morphology and structure of delaminating MXene Ti_3C_2 flakes. The results indicated that chemical modification for MXene multilayers by aryl diazonium salts induced swelling that conversely weakened the bonds between MX layers, hence leading to large-scale delamination of multilayered MXene Ti_3C_2via mild sonication. Advantages of the present approach rely not only on the simplicity and efficiency of the delamination procedure but also on the grafting of aryl groups to MXene surfaces, highly suitable for further applications of the newly discovered two-dimensional materials.

Comparison of Inhibitory Activities of meta and para Substituted N-aryl 3-Hydroxypyridin-4-one Mannosides Towards Type 1 Fimbriated E. coli

Directory of Open Access Journals (Sweden)

Vesna Petrović Peroković

2016-06-01

Full Text Available In uropathogenic Escherichia coli, mannose-specific adhesion is mediated by the FimH adhesin located at the tip of type 1 fimbriae. Novel mannosylated N-aryl substituted 3-hydroxypyridin-4ones with meta substituents on the aryl part of the molecule were prepared, and their inhibitory properties towards the adhesion of E. coli to guinea pig erythrocytes explored using the hemagglutination assay. These results were compared with inhibitory potencies of analogous para derivatives. The assays revealed greater preference of FimH towards para substituted compounds in general, with p-nitro and p-methoxy substituted substrates being much more effective then the hydrophobic p-methyl compound. When substituents are in meta position the positive affect on the binding of compounds in the FimH binding site was observed with all compounds tested but the structure with an alkyl group was shown to be the most effective one. This study provides guidelines for the rational design of novel, more effective series of FimH antagonists. This work is licensed under a Creative Commons Attribution 4.0 International License.

Visible light catalyzed methylsulfoxidation of (het)aryl diazonium salts using DMSO.

Science.gov (United States)

Pramanik, Mukund M D; Rastogi, Namrata

2016-06-30

The visible light catalyzed methylsulfoxidation of (het)aryl diazonium salts using DMSO is illustrated. This is the first example of DMSO being used as the source of the methylsulfinyl group. The procedure tolerates a wide range of functional groups on (het)aryl diazonium salts and provides aryl methyl sulfoxides in excellent yields under mild reaction conditions.

Application of a Heterogeneous Chiral Titanium Catalyst Derived from Silica-Supported 3-Aryl H8-BINOL to Enantioselective Alkylation and Arylation of Aldehydes.

Science.gov (United States)

Akai, Junichiro; Watanabe, Satoshi; Michikawa, Kumiko; Harada, Toshiro

2017-07-07

A 3-aryl H 8 -BINOL was grafted on the surface of silica gel using a hydrosilane derivative as a precursor, and the resulting silica-supported ligand (6 mol %) was employed in the enantioselective alkylation and arylation of aldehydes in the presence of Ti(O i Pr) 4 . The reactions using Et 2 Zn, Et 3 B, and aryl Grignard reagents all afforded the corresponding adducts in high enantioselectivities and yields. The silica-immobilized titanium catalyst could be reused up to 14 times without appreciable deterioration of the activity.

Nano-TiCl4.SiO2: A Versatile and Efficient Catalyst for Synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes

OpenAIRE

B. F. Mirjalili; A. Bamoniri; L. Zamani

2013-01-01

Nano-silica supported titanium tetrachloride (TiCl4.SiO2) was prepared and used as an acid catalyst for the 14-aryl or alkyl-14H-dibenzo[a,,j]xanthenesreaction under solvent-free conditions. Compared to the classical 14-aryl or alkyl-14H-dibenzo[a,j]xanthenesreaction conditions, this method consistently has the advantage of excellent yields, mild reaction conditions, ease of workup, survival of different functional groups and short reaction times.

Photocatalytic Arylation of Alkenes, Alkynes and Enones with Diazonium Salts

OpenAIRE

Schroll, Peter; Hari, Durga Prasad; König, Burkhard

2012-01-01

Teaching old dogs new tricks: Visible light photoredox catalysis improves the classic Meerwein arylation protocol significantly and allows the light-controlled arylation of alkenes, alkynes and enones by diazonium salts.

Characterization of substituted aryl meroterpenoids from red seaweed Hypnea musciformis as potential antioxidants.

Science.gov (United States)

Chakraborty, Kajal; Joseph, Deepu; Joy, Minju; Raola, Vamshi Krishna

2016-12-01

The ethyl acetate fraction of red seaweed Hypnea musciformis was purified to yield three substituted aryl meroterpenoids, namely, 2-(tetrahydro-5-(4-hydroxyphenyl)-4-pentylfuran-3-yl)-ethyl-4-hydroxybenzoate (1), 2-2-[(4-hydroxybenzoyl)-oxy]-ethyl-4-methoxy-4-2-[(4-methylpentyl)oxy]-3,4-dihydro-2H-6-pyranylbutanoic acid (2) and 3-((5-butyl-3-methyl-5,6-dihydro-2H-pyran-2-yl)-methyl)-4-methoxy-4-oxobutyl benzoate (3). The structures of these compounds, as well as their relative stereochemistries, were confirmed by exhaustive NMR spectroscopic data analyses. Compound 1 exhibited similar 2,2'-diphenylpicrylhydrazyl radical inhibiting and Fe(2+) ion chelating activities (IC50 25.05 and 350.7μM, respectively) as that of commercial antioxidant gallic acid (IC50 32.3 and 646.6μM, respectively), followed by 3 (IC50 231.2 and 667.9μM, respectively), and 2 (IC50 322.4 and 5115.3μM, respectively), in descending order of activities. Structure-activity relationship analysis revealed that the antioxidant activities of these compounds were directly proportional to the steric and hydrophobic parameters. The seaweed derived aryl meroterpenoids might serve as potential lead antioxidative molecules for use in pharmaceutical and food industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enantioselective Rhodium Enolate Protonations. A New Methodology for the Synthesis of β2-Amino Acids

Science.gov (United States)

Sibi, Mukund P.; Tatamidani, Hiroto; Patil, Kalyani

2008-01-01

Rhodium catalyzed conjugate addition of an aryl boronic acid to α-methylamino acrylates followed by enantioselective protonation of the oxa-π-allylrhodium intermediate provides access to aryl substituted β2-amino acids. The impact of the different variables of the reaction on the levels of enantioselectivity has been assessed. PMID:15957893

Nickel-catalyzed synthesis of aryl trifluoromethyl sulfides at room temperature.

Science.gov (United States)

Zhang, Cheng-Pan; Vicic, David A

2012-01-11

Inexpensive nickel-bipyridine complexes were found to be active for the trifluoromethylthiolation of aryl iodides and aryl bromides at room temperature using the convenient [NMe(4)][SCF(3)] reagent. © 2011 American Chemical Society

Divergent unprotected peptide macrocyclisation by palladium-mediated cysteine arylation.

Science.gov (United States)

Rojas, Anthony J; Zhang, Chi; Vinogradova, Ekaterina V; Buchwald, Nathan H; Reilly, John; Pentelute, Bradley L; Buchwald, Stephen L

2017-06-01

Macrocyclic peptides are important therapeutic candidates due to their improved physicochemical properties in comparison to their linear counterparts. Here we detail a method for a divergent macrocyclisation of unprotected peptides by crosslinking two cysteine residues with bis-palladium organometallic reagents. These synthetic intermediates are prepared in a single step from commercially available aryl bis-halides. Two bioactive linear peptides with cysteine residues at i , i + 4 and i , i + 7 positions, respectively, were cyclised to introduce a diverse array of aryl and bi-aryl linkers. These two series of macrocyclic peptides displayed similar linker-dependent lipophilicity, phospholipid affinity, and unique volume of distributions. Additionally, one of the bioactive peptides showed target binding affinity that was predominantly affected by the length of the linker. Collectively, this divergent strategy allowed rapid and convenient access to various aryl linkers, enabling the systematic evaluation of the effect of appending unit on the medicinal properties of macrocyclic peptides.

Nano-TiCl4.SiO2: A Versatile and Efficient Catalyst for Synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes

Directory of Open Access Journals (Sweden)

B. F. Mirjalili

2013-12-01

Full Text Available Nano-silica supported titanium tetrachloride (TiCl4.SiO2 was prepared and used as an acid catalyst for the 14-aryl or alkyl-14H-dibenzo[a,,j]xanthenesreaction under solvent-free conditions. Compared to the classical 14-aryl or alkyl-14H-dibenzo[a,j]xanthenesreaction conditions, this method consistently has the advantage of excellent yields, mild reaction conditions, ease of workup, survival of different functional groups and short reaction times.

Enantioselective rhodium enolate protonations. A new methodology for the synthesis of beta2-amino acids.

Science.gov (United States)

Sibi, Mukund P; Tatamidani, Hiroto; Patil, Kalyani

2005-06-23

[reaction: see text] Rhodium-catalyzed conjugate addition of an aryl boronic acid to alpha-methylamino acrylates followed by enantioselective protonation of the oxa-pi-allylrhodium intermediate provides access to aryl-substituted beta(2)-amino acids. The impact of the different variables of the reaction on the levels of enantioselectivity has been assessed.

N-heterocycle carbene (NHC)-ligated cyclopalladated N,N-dimethylbenzylamine: a highly active, practical and versatile catalyst for the Heck-Mizoroki reaction.

Science.gov (United States)

Peh, Guang-Rong; Kantchev, Eric Assen B; Zhang, Chi; Ying, Jackie Y

2009-05-21

The wide dissemination of catalytic protocols in academic and industrial laboratories is facilitated by the development of catalysts that are not only highly active but also user-friendly, stable to moisture, air and long term storage and easy to prepare on a large scale. Herein we describe a protocol for the Heck-Mizoroki reaction mediated by cyclopalladated N,N-dimethylbenzylamine (dmba) ligated with a N-heterocyclic carbene, 1,3-bis(mesityl)imidazol-2-ylidene (IMes), that fulfils these criteria. The precatalyst can be synthesized on approximately 100 g scale by a tri-component, sequential, one-pot reaction of N,N-dimethylbenzylamine, PdCl2 and IMes.HCl in refluxing acetonitrile in air in the presence of K2CO3. This single component catalyst is stable to air, moisture and long term storage and can be conveniently dispensed as a stock solution in NMP. It mediates the Heck-Mizoroki reaction of a range of aryl- and heteroaryl bromides in reagent grade NMP at the 0.1-2 mol% range without the need for rigorous anhydrous techniques or a glovebox, and is active even in air. The catalyst is capable of achieving very high levels of catalytic activity (TON of up to 5.22 x 10(5)) for the coupling of a deactivated arylbromide, p-bromoanisole, with tBu acrylate as a benchmark substrate pair. A wide range of aryl bromides, iodides and, for the first time with a NHC-Pd catalyst, a triflate was coupled with diverse acrylate derivatives (nitrile, tert-butyl ester and amides) and styrene derivatives. The use of excess (>2 equiv.) of the aryl bromide and tert-butyl acrylate leads to mixture of tert-butyl beta,beta-diarylacrylate and tert-butyl cinnamate derivatives depending on the substitution pattern of the aryl bromide. Electron rich m- and p-substituted arylbromides give the diarylated products exclusively, whereas electron-poor aryl bromides give predominantly mono-arylated products. For o-substituted aryl bromides, no doubly arylated products could be obtained under any

Mechanistic evidence for a ring-opening pathway in the Pd-catalyzed direct arylation of benzoxazoles

DEFF Research Database (Denmark)

Sanchez, R.S.; Zhuravlev, Fedor

2007-01-01

The direct Pd-catalyzed arylation of 5-substituted benzoxazoles, used as a mechanistic model for 1,3-azoles, was investigated experimentally and computationally. The results of the primary deuterium kinetic isotope effect, Hammett studies, and H/D exchange were shown to be inconsistent with the r......The direct Pd-catalyzed arylation of 5-substituted benzoxazoles, used as a mechanistic model for 1,3-azoles, was investigated experimentally and computationally. The results of the primary deuterium kinetic isotope effect, Hammett studies, and H/D exchange were shown to be inconsistent...... with the rate-limiting electrophilic or concerted palladation. A mechanism, proposed on the basis of kinetic and computational studies, includes generation of isocyanophenolate as the key step. The DFT calculations suggest that the overall catalytic cycle is facile and is largely controlled by the C-H acidity...

General synthesis of 2,1-benzisoxazoles (anthranils) from nitroarenes and benzylic C-H acids in aprotic media promoted by combination of strong bases and silylating agents.

Science.gov (United States)

Wiȩcław, Michał; Bobin, Mariusz; Kwast, Andrzej; Bujok, Robert; Wróbel, Zbigniew; Wojciechowski, Krzysztof

2015-11-01

Carbanions of phenylacetonitriles, benzyl sulfones, and dialkyl benzylphosphonates add nitroarenes at the ortho-position to the nitro group to form [Formula: see text]-adducts that, upon treatment with trialkylchlorosilane and additional base (t-BuOK or DBU), transform into 3-aryl-2,1-benzisoxazoles in moderate-to-good yields.

Gold-Catalyzed Formal C-C Bond Insertion Reaction of 2-Aryl-2-diazoesters with 1,3-Diketones.

Science.gov (United States)

Ren, Yuan-Yuan; Chen, Mo; Li, Ke; Zhu, Shou-Fei

2018-06-29

The transition-metal-catalyzed formal C-C bond insertion reaction of diazo compounds with monocarbonyl compounds is well established, but the related reaction of 1,3-diketones instead gives C-H bond insertion products. Herein, we report a protocol for a gold-catalyzed formal C-C bond insertion reaction of 2-aryl-2-diazoesters with 1,3-diketones, which provides efficient access to polycarbonyl compounds with an all-carbon quaternary center. The aryl ester moiety plays a crucial role in the unusual chemoselectivity, and the addition of a Brønsted acid to the reaction mixture improves the yield of the C-C bond insertion product. A reaction mechanism involving cyclopropanation of a gold carbenoid with an enolate and ring-opening of the resulting donor-acceptor-type cyclopropane intermediate is proposed. This mechanism differs from that of the traditional Lewis-acid-catalyzed C-C bond insertion reaction of diazo compounds with monocarbonyl compounds, which involves a rearrangement of a zwitterion intermediate as a key step. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

N-BUTYL SUBSTITUTED N-HETEROCYCLIC CARBENE-PD(II-PYRIDINE (PEPPSI COMPLEXES: SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY IN THE SUZUKI-MIYAURA REACTION

Directory of Open Access Journals (Sweden)

Rukiye Fırıncı

2016-08-01

Full Text Available A series of N-butyl substituted imidazolium salts, (1a-c and their pyridine enhanced precatalyst preparation stabilization and initiation (PEPPSI themed palladium N-heterocyclic carbene complexes (2a-c were synthesized and characterized. Pd-NHC complexes were fully determined by elemental analysis and spectroscopic. The synthesized complexes were tested in Suzuki-Miyaura cross-coupling reaction. These complexes were found to be efficient catalysts for the Suzuki-Miyaura reaction of phenylboronic acid with aryl bromides.

Surface modified MXene Ti{sub 3}C{sub 2} multilayers by aryl diazonium salts leading to large-scale delamination

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongbing [College of Mechanics and Materials, Hohai University, Nanjing, Jiangsu Province 210098 (China); Department of Mathematics and Physics, Nanjing Institute of Technology, Nanjing, Jiangsu Province 211167 (China); Zhang, Jianfeng, E-mail: jfzhang_sic@163.com [College of Mechanics and Materials, Hohai University, Nanjing, Jiangsu Province 210098 (China); Wu, Yuping; Huang, Huajie; Li, Gaiye; Zhang, Xin; Wang, Zhuyin [College of Mechanics and Materials, Hohai University, Nanjing, Jiangsu Province 210098 (China)

2016-10-30

Highlights: • A novel and simple method to delaminate MXene Ti{sub 3}C{sub 2} multilayers. • Surface modification using aryl diazonium salts induced swelling that conversely weakened the bonds between MXene layers. • The grafting of phenylsulfonic acid groups on MXene surfaces resulted in excellent water dispersibility. - Abstract: Herein we report a simple and facile method to delaminate MXene Ti{sub 3}C{sub 2} multilayers by the assistance of surface modification using aryl diazonium salts. The basic strategy involved the preparation of layered MAX Ti{sub 3}AlC{sub 2} and the exfoliation of Ti{sub 3}AlC{sub 2} into Ti{sub 3}C{sub 2} multilayers, followed by Na{sup +} intercalation and surface modification using sulfanilic acid diazonium salts. The resulting chemically grafted Ti{sub 3}C{sub 2} flakes were characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the presence of the surface organic species. Ultraviolet-visible spectroscopy revealed that surface-modified MXene Ti{sub 3}C{sub 2} sheets disperse well in water and the solutions obey Lambert–Beer’s law. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to demonstrate the morphology and structure of delaminating MXene Ti{sub 3}C{sub 2} flakes. The results indicated that chemical modification for MXene multilayers by aryl diazonium salts induced swelling that conversely weakened the bonds between MX layers, hence leading to large-scale delamination of multilayered MXene Ti{sub 3}C{sub 2}via mild sonication. Advantages of the present approach rely not only on the simplicity and efficiency of the delamination procedure but also on the grafting of aryl groups to MXene surfaces, highly suitable for further applications of the newly discovered two-dimensional materials.

Ultrasonic promoted catalyst-free N-formylation of amines in neutral ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate

Directory of Open Access Journals (Sweden)

Vinod T. Kamble

2017-05-01

Full Text Available A catalyst-free, simple and efficient protocol for N-formylation of alkyl, aryl, and heteroaryl amines with formic acid under ultrasonic irradiation at room temperature using 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim]BF4 as a neutral medium is described.

The synthesis of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides by the microwave-assisted Pudovik reaction

Directory of Open Access Journals (Sweden)

Erika Bálint

2017-01-01

Full Text Available A family of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides was synthesized by the microwave-assisted solvent-free addition of dialkyl phosphites and diphenylphosphine oxide, respectively, to imines formed from benzaldehyde derivatives and primary amines. After optimization, the reactivity was mapped, and the fine mechanism was evaluated by DFT calculations. Two α-aminophosphonates were subjected to an X-ray study revealing a racemic dimer formation made through a N–H···O=P intermolecular hydrogen bridges pair.

Influence of Functionality on Direct Arylation of Model Systems as a Route Toward Fluorinated Copolymers via Direct Arylation Polymerization (DArP)

DEFF Research Database (Denmark)

Livi, Francesco; Gobalasingham, Nemal S.; Bundgaard, Eva

2015-01-01

A screening of direct arylation conditions on amodel small molecule system is carried out to develop suitableconditions for the direct arylation polymerization (DArP) of fluorinatedcopolymers, which are incompatible with conditionspreviously utilized successfully for nonfluorinated systems. Themo......,4-phenylene)dithiophene. Polymers arefree of β-defects and significant homocoupling. This work furtherunderscores the attractive simplicity, relevance, and easeof DArP while reconfirming its broad compatibility withincreasingly popular fluorinated copolymers....

Synthesis of aryl b-N-acetylglucosamine desmodified at C-6 as potential antimicrobial agents; Sintese de b-N-acetilglicosaminideos de arila modificados em C-6 como potenciais agentes antimicrobianos

Energy Technology Data Exchange (ETDEWEB)

Manfrini, Rozangela Magalhaes; Souza Filho, Jose Dias de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas; Figueireido, Rute Cunha; D' Angelis, Allison Fabiano; Prado, Maria Auxiliadora Fontes; Nunan, Elziria de Aguiar; Martins, Gabriela Aires; Alves, Ricardo Jose [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Farmacia. Dept. de Produtos Farmaceuticos]. E-mail: ricardodylan@farmacia.ufmg.br

2008-07-01

We report herein the synthesis of aryl beta-N-acetylglucosaminides containing azido, amino and acetamido groups at C-6 as potential antimicrobial agents. It was expected that these compounds could interfere with the biosynthesis and/or biotransformation of Nacetylglucosamine in fungi and bacteria. None of the compounds showed antimicrobial activity against bacteria (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), filamentous fungus (Aspergillus niger) and yeasts (Saccharomyces cerevisae, Candida albicans and Candida tropicallis), at the concentration of 1 mg/mL in agar diffusion assay. (author)

Electronic structure and tautomerism of aryl ketones

International Nuclear Information System (INIS)

Novak, Igor; Klasinc, Leo; Šket, Boris; McGlynn, S.P.

2015-01-01

Graphical abstract: Photoelectron spectroscopy, tautomerism. - Highlights: • UV photoelectron spectroscopy of aryl ketones. • The relative stability of tautomers and their electronic structures. • The factors influencing tautomerism. - Abstract: The electronic structures of several aryl ketones (AK) and their α-halo derivatives have been studied by UV photoelectron spectroscopy (UPS). The relative stabilities of keto–enol tautomers have been determined using high-level ab initio calculations and the results were used in the analysis of UPS spectra. The main features of electronic structure and tautomerism of the AK derivatives are discussed

Electronic structure and tautomerism of aryl ketones

Energy Technology Data Exchange (ETDEWEB)

Novak, Igor, E-mail: inovak@csu.edu.au [Charles Sturt University, POB 883, Orange, NSW 2800 (Australia); Klasinc, Leo, E-mail: klasinc@irb.hr [Physical Chemistry Department, Ruđer Bošković Institute, HR-10002 Zagreb (Croatia); Šket, Boris, E-mail: Boris.Sket@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 (Slovenia); McGlynn, S.P., E-mail: sean.mcglynn@chemgate.chem.lsu.edu [Louisiana State University, Baton Rouge, LA 70803 (United States)

2015-07-15

Graphical abstract: Photoelectron spectroscopy, tautomerism. - Highlights: • UV photoelectron spectroscopy of aryl ketones. • The relative stability of tautomers and their electronic structures. • The factors influencing tautomerism. - Abstract: The electronic structures of several aryl ketones (AK) and their α-halo derivatives have been studied by UV photoelectron spectroscopy (UPS). The relative stabilities of keto–enol tautomers have been determined using high-level ab initio calculations and the results were used in the analysis of UPS spectra. The main features of electronic structure and tautomerism of the AK derivatives are discussed.

Purposeful search of hypoglycemic agents among N-arylcarbamides and N-arylsulfamides of [2-(3-R-1Н-[1,2,4]triazole-5-ylphenyl]amines

Directory of Open Access Journals (Sweden)

S. V. Kholodnyak

2015-08-01

Full Text Available Aim. Formation of N-arylcarbamides and N-arylsulfamides as result of interaction of 2-(3-R-1Н-[1,2,4]triazole-5-ylphenyl]amines with electrophilic reagents (arylisocyanates and arylsulfonylchlorides is described in presented article. The optimal conditions for mentioned reactions have been proposed. Methods and results. It has been evaluated that N-arylcarbamides of 2-(3-aryl-1H-1,2,4-triazole-5-ylphenyl]amines while heating over 90°C in glacial acetic acid undergo cyclisation followed by formation of corresponding 2-aryl-[1,2,4]triazolo[1,5-c]quinazoline-5(6Н-ones. Purity and structure of synthesized compounds has been proved by elemental analysis, 1H NMR-, chromato-mass and mass-spectra. Conclusion. It has been established, that compound 2.1 during evaluation of specific pharmacologic activities on oral glucose tolerance test (OGTT, rapid insulin and adrenaline test models exhibited action which is comparable to activities of reference-drugs «Metformin» and «Gliclazide».

Facile synthetic approach for 5-aryl-9-hydroxypyrano [3,2-f] indole-2(8H-one

Directory of Open Access Journals (Sweden)

Cheng Wang

2016-11-01

Full Text Available An appropriate method for the synthesis of 5-aryl-9-hydroxypyrano[3,2-f]indole-2(8H-one was described. The targeted compounds were obtained starting from vanillin via nine steps. Interestingly, in the final cyclization step, the intermediate 4-(2-halogeno phenyl-7-methoxy-1H-indole-6-yl propiolate could convert directly into the final product in one step reaction using PtCl4 or Pd(PPh34/trifluoroacetic acid as catalysts. The possible catalytic mechanism for PtCl4 and Pd(PPh34/trifluoroacetic acid was discussed.

Characterization of carbohydrates using highly fluorescent 2-aminobenzoic acid tag following gel electrophoresis of glycoproteins.

Science.gov (United States)

Anumula, K R; Du, P

1999-11-15

Application of the most sensitive fluorescent label 2-aminobenzoic acid (anthranilic acid, AA) for characterization of carbohydrates from the glycoproteins ( approximately 15 pmol) separated by polyacrylamide gel electrophoresis is described. AA label is used for the determination of both monosaccharide composition and oligosaccharide map. For the monosaccharide determination, bands containing the glycoprotein of interest are excised from the polyvinylidene fluoride (PVDF) membrane blots, hydrolyzed in 20% trifluoroacetic acid, derivatized, and analyzed by C-18 reversed-phase high-performance liquid chromatography. For the oligosaccharide mapping, bands were digested with peptide N-glycosidase F (PNGase F) in order to release the N-linked oligosaccharides, derivatized, and analyzed by normal-phase anion-exchange chromatography. For convenience, the PNGase F digestion was performed in 1:100 diluted ammonium hydroxide overnight. The oligosaccharide yield from ammonium hydroxide-PNGase F digestion was better or equal to all the other reported procedures, and the presumed "oligosaccharide-amine" product formed in the reaction mixture did not interfere with labeling of the oligosaccharides under the conditions used for derivatization. Sequencing of oligosaccharides can be performed using the same mapping method following treatment with an array of glycosidases. In addition, the mapping method is useful for determining the relative and simultaneous distribution of sialic acid and fucose. Copyright 1999 Academic Press.

CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO_2 at room temperature

International Nuclear Information System (INIS)

Yu, B.; Yang, Z.Z.; Zhao, Y.F.; Zhang, H.Y.; Yang, P.; Gao, X.; Liu, Z.M.

2017-01-01

A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO_2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynyl-silane intermediate was first in situ generated, which was then trapped by CO_2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure. (authors)

Study of the Air-Tolerant 1,3-Diphosphacyclobutane-2,4-diyl through the Direct Arylation.

Science.gov (United States)

Ito, Shigekazu

2018-04-01

Installing π-functional substituents on the skeletal phosphorus atoms of the air-tolerant 1,3-diphosphacyclobutane-2,4-diyl unit are promising for tuning the open-shell singlet P-heterocyclic chromophore. The sterically encumbered 1,3-diphosphaCycloButen-4-yl Anion (CBA), generated from the phosphorus-carbon triple bond, was available for the regioselective arylation via nucleophilic aromatic substitution (S N Ar) reaction, addition to arynes, and single-electron transfer (SET) process affording the corresponding P-arylated 1,3-diphosphacyclobutane-2,4-diyls. The photo-absorption and redox properties correlated with the effects of the aryl substituents on the 1,3-diphosphacyclobutane-2,4-diyl unit. The X-ray analyses enabled not only to discuss the metric parameters but also to visualize the radicalic electrons via the electron-density distribution analysis. The electron-donating character of the P-heterocyclic chromophores induced the p-type semiconductor behavior. Detection of hydrogen fluoride via formation of the 1λ 5 ,3λ 5 -diphosphete derivative was also developed. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stereoselective synthesis of diazaspiro[5.5]undecane derivatives via base promoted [5+1] double Michael addition of N,N-dimethylbarbituric acid to diaryliedene acetones

Directory of Open Access Journals (Sweden)

Mohammad Shahidul Islam

2017-01-01

Full Text Available The nitrogen containing spiro-heterocycle is one of the privileged synthetic motif that constitutes various naturally occurring molecules and displays a broad range of pharmaceutical and biological activities. A new methodology was developed for the synthesis of 2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones spiro-heterocyclic derivatives via cascade cyclization of [5+1] double Michael addition reaction of N,N-dimethylbarbituric acid with the derivatives of diaryldivinylketones in the presence of diethylamine at ambient temperature. The developed protocol is highly capable of furnishing diazaspiro[5.5]undecane derivatives 3a–m in excellent yields (up to 98%, from easily accessible symmetric and non-symmetric divinylketones 2a–m, containing aryl and heteroaryl substituents. The diazaspiro-heterocyclic structure was mainly elucidated by NMR and X-ray crystallographic techniques. The single-crystal X-ray studies revealed that, the cyclohexanone unit of spirocycles often prefers a chair conformation rather than twisted conformation. The intermolecular hydrogen bonding and CArH⋯π, π–π stacking interactions driving forces are mainly responsible for the crystal packing.

The sonochemical arylation of malonic esters mediated by manganese triacetate.

Science.gov (United States)

Meciarova, M; Toma, S; Luche, J L

2001-04-01

The intermolecular arylation of malonate esters in acetic acid solution in the presence of manganese(III) triacetate is known to proceed via an Electron Transfer mechanism. Under sonication, this reaction undergoes only minor changes. In contrast, the intramolecular reaction of dimethyl alpha-(3-phenylpropyl)malonate provides a new case of sonochemical switching, with the formation of compounds 7-9, while conventional thermal conditions generate only the bicyclic compound 6. Reactions using the more powerful oxidant, cerium ammonium nitrate are governed by the formation of the nitrate ester 11. Compounds 7-9 are isolated in yields lower than with MnTA, and in proportions depending on the conditions, thermal or sonochemical.

Identification of 1-Aryl-1H-1,2,3-triazoles as Potential New Antiretroviral Agents.

Science.gov (United States)

Gonzaga, Daniel T G; Souza, Thiago M L; Andrade, Viviane M M; Ferreira, Vitor F; de C da Silva, Fernando

2018-01-01

Low molecular weight 1-Aryl-1H-1,2,3-triazoles are endowed with various types of biological activities, such as against cancer, HIV and bacteria. Despite the existence of six different classes of antiretroviral drugs in clinical use, HIV/AIDS continue to be an on growing public health problem. In the present study, we synthesized and evaluated thirty 1-Aryl-1H-1,2,3-triazoles against HIV replication. The compounds were prepared by Huisgen 1,3-dipolar cycloaddition protocol catalyzed by Cu(I) between aryl azides and propargylic alcohol followed by further esterification and etherification from a nucleophilic substitution with acid chlorides or alkyl bromides in good yields. The compounds were submitted to the inhibition of HIV replication and evaluation of their cytotoxicity. Initially, the compounds were screened at 10 µM and the most active were further evaluated in order to obtain some pharmacological parameters. Thirty molecules were evaluated, six were selected - because they inhibited more than 80% HIV replication. We further showed that two of these compounds are 8-times more potent, and less cytotoxic, than nevirapine, an antiretroviral drug in clinical use. We identified very simple triazoles with promissing antiretroviral activities that led to the development of new drugs against AIDS. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Anthranilate phosphoribosyltransferase: Binding determinants for 5'-phospho-alpha-d-ribosyl-1'-pyrophosphate (PRPP) and the implications for inhibitor design.

Science.gov (United States)

Evans, Genevieve L; Furkert, Daniel P; Abermil, Nacim; Kundu, Preeti; de Lange, Katrina M; Parker, Emily J; Brimble, Margaret A; Baker, Edward N; Lott, J Shaun

2018-02-01

Phosphoribosyltransferases (PRTs) bind 5'-phospho-α-d-ribosyl-1'-pyrophosphate (PRPP) and transfer its phosphoribosyl group (PRib) to specific nucleophiles. Anthranilate PRT (AnPRT) is a promiscuous PRT that can phosphoribosylate both anthranilate and alternative substrates, and is the only example of a type III PRT. Comparison of the PRPP binding mode in type I, II and III PRTs indicates that AnPRT does not bind PRPP, or nearby metals, in the same conformation as other PRTs. A structure with a stereoisomer of PRPP bound to AnPRT from Mycobacterium tuberculosis (Mtb) suggests a catalytic or post-catalytic state that links PRib movement to metal movement. Crystal structures of Mtb-AnPRT in complex with PRPP and with varying occupancies of the two metal binding sites, complemented by activity assay data, indicate that this type III PRT binds a single metal-coordinated species of PRPP, while an adjacent second metal site can be occupied due to a separate binding event. A series of compounds were synthesized that included a phosphonate group to probe PRPP binding site. Compounds containing a "bianthranilate"-like moiety are inhibitors with IC 50 values of 10-60μM, and K i values of 1.3-15μM. Structures of Mtb-AnPRT in complex with these compounds indicate that their phosphonate moieties are unable to mimic the binding modes of the PRib or pyrophosphate moieties of PRPP. The AnPRT structures presented herein indicated that PRPP binds a surface cleft and becomes enclosed due to re-positioning of two mobile loops. Copyright © 2017 Elsevier B.V. All rights reserved.

Aryl Insertion vs Aryl-Aryl Coupling in C,C-Chelated Organoborates: The "Missing Link" of Tetraarylborate Photochemistry.

Science.gov (United States)

Radtke, Julian; Mellerup, Soren K; Bolte, Michael; Lerner, Hans-Wolfram; Wang, Suning; Wagner, Matthias

2018-06-14

The photoreactivity of 9-borafluorene-based, C,C-chelated organoborates was investigated. Unlike the related tetraarylborates, the charge-transfer transitions imparted by the biphenyl chelate lead to selective insertion of one aryl substituent into the endocyclic B-C bond of the 9-borafluorene moiety, resulting in the formation of boratanorcaradienes. This photoreaction likely proceeds according to a Zimmerman rearrangement, which is analogous to one of the initially proposed mechanisms for tetraarylborates and provides additional insight into these long-debated photochemical reactions.

Phosphorylation inhibits DNA-binding of alternatively spliced aryl hydrocarbon receptor nuclear translocator

International Nuclear Information System (INIS)

Kewley, Robyn J.; Whitelaw, Murray L.

2005-01-01

The basic helix-loop-helix/PER-ARNT-SIM homology (bHLH/PAS) transcription factor ARNT (aryl hydrocarbon receptor nuclear translocator) is a key component of various pathways which induce the transcription of cytochrome P450 and hypoxia response genes. ARNT can be alternatively spliced to express Alt ARNT, containing an additional 15 amino acids immediately N-terminal to the DNA-binding basic region. Here, we show that ARNT and Alt ARNT proteins are differentially phosphorylated by protein kinase CKII in vitro. Phosphorylation had an inhibitory effect on DNA-binding to an E-box probe by Alt ARNT, but not ARNT, homodimers. This inhibitory phosphorylation occurs through Ser77. Moreover, a point mutant, Alt ARNT S77A, shows increased activity on an E-box reporter gene, consistent with Ser77 being a regulatory site in vivo. In contrast, DNA binding by an Alt ARNT/dioxin receptor heterodimer to the xenobiotic response element is not inhibited by phosphorylation with CKII, nor does Alt ARNT S77A behave differently from wild type Alt ARNT in the context of a dioxin receptor heterodimer

Rapid determination of the aromatic compounds methyl-anthranilate, 2'-aminoacetophenone and furaneol by GC-MS: Method validation and characterization of grape derivatives.

Science.gov (United States)

Prudêncio Dutra, Maria da Conceição; de Souza, Joyce Fagundes; Viana, Arão Cardoso; de Oliveira, Débora; Pereira, Giuliano Elias; Dos Santos Lima, Marcos

2018-05-01

A methodology for the rapid determination of the aromatic compounds methyl anthranilate (MA), 2'-aminoacetophenone (2-AAP) and furaneol by GC-MS was validated and used to characterize grape juice and wine elaborated with the new Brazilian grape varieties cultivated in northeastern Brazil, and Brazilian grape nectars. The method presented linearity (R 2  ˃ 0.9952), good accuracy (CV furaneol in the aroma of grape juice and wines elaborated with the new Brazilian grape varieties. Copyright © 2018 Elsevier Ltd. All rights reserved.

The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor (nAChR) ligands. Part 1: the influence of different hydrogen bond acceptor systems on alkyl and (hetero)aryl substituents.

Science.gov (United States)

Eibl, Christoph; Tomassoli, Isabelle; Munoz, Lenka; Stokes, Clare; Papke, Roger L; Gündisch, Daniela

2013-12-01

3,7-Diazabicyclo[3.3.1]nonane is a naturally occurring scaffold interacting with nicotinic acetylcholine receptors (nAChRs). When one nitrogen of the 3,7-diazabicyclo[3.3.1]nonane scaffold was implemented in a carboxamide motif displaying a hydrogen bond acceptor (HBA) functionality, compounds with higher affinities and subtype selectivity for α4β2(∗) were obtained. The nature of the HBA system (carboxamide, sulfonamide, urea) had a strong impact on nAChR interaction. High affinity ligands for α4β2(∗) possessed small alkyl chains, small un-substituted hetero-aryl groups or para-substituted phenyl ring systems along with a carboxamide group. Electrophysiological responses of selected 3,7-diazabicyclo[3.3.1]nonane derivatives to Xenopus oocytes expressing various nAChR subtypes showed diverse activation profiles. Compounds with strongest agonistic profiles were obtained with small alkyl groups whereas a shift to partial agonism/antagonism was observed for aryl substituents. Copyright © 2013 Elsevier Ltd. All rights reserved.

Suzuki coupling reactions catalyzed by poly(N-ethyl-4-vinylpyridinium bromide stabilized palladium nanoparticles in aqueous solution

Directory of Open Access Journals (Sweden)

2008-04-01

Full Text Available InIn this work, it was investigated to use of poly(N-ethyl-4-vinylpyridinium bromide stabilized palladium nanoparticles in the Suzuki reaction between phenylboronic acid and aryl halides in aqueous solution. The nanoparticles were isolated and re-used several times with low loss of activity.

Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism

DEFF Research Database (Denmark)

Antonacci, Giuseppe; Ahlburg, Andreas; Fristrup, Peter

2017-01-01

The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group....... Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped. The cross-coupling reaction is therefore believed to proceed by an SRN1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor...

Functionalized carbon nanofibers as solid acid catalysts for transesterification

NARCIS (Netherlands)

Stellwagen, D.R.; van der Klis, Frits; van Es, D.S.; de Jong, K.P.; Bitter, J.H.

2013-01-01

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

Functionalized carbon nanofibers as solid-acid catalysts for transesterification

NARCIS (Netherlands)

Stellwagen, D.R.; Klis, van der F.; Es, van D.S.; Jong, de K.P.; Bitter, J.H.

2013-01-01

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

Discovery of Azetidinone Acids as Conformationally-Constrained Dual PPARalpha/gamma Agonists

Energy Technology Data Exchange (ETDEWEB)

Wang, W.; Devasthale, P; Farrelly, D; Gu, L; Harrity, T; Cap, M; Chu, C; Kunselman, L; Morgan, N; et. al.

2008-01-01

A novel class of azetidinone acid-derived dual PPAR{alpha}/{gamma} agonists has been synthesized for the treatment of diabetes and dyslipidemia. The preferred stereochemistry in this series for binding and functional agonist activity against both PPARa and PPAR? receptors was shown to be 3S,4S. Synthesis, in vitro and in vivo activities of compounds in this series are described. A high-yielding method for N-arylation of azetidinone esters is also described.

Decarboxylative Aminomethylation of Aryl- and Vinylsulfonates through Combined Nickel- and Photoredox-Catalyzed Cross-Coupling

KAUST Repository

Fan, Lulu

2016-09-23

A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C−O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields.

Decarboxylative Aminomethylation of Aryl- and Vinylsulfonates through Combined Nickel- and Photoredox-Catalyzed Cross-Coupling

KAUST Repository

Fan, Lulu; Jia, Jiaqi; Hou, Hong; Lefebvre, Quentin; Rueping, Magnus

2016-01-01

A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C−O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields.

Aryl hydrocarbon receptor–ligand axis mediates pulmonary fibroblast migration and differentiation through increased arachidonic acid metabolism

International Nuclear Information System (INIS)

Su, Hsiang-Han; Lin, Hsin-Ting; Suen, Jau-Ling; Sheu, Chau Chyun; Yokoyama, Kazunari K.; Huang, Shau-Ku; Cheng, Chih Mei

2016-01-01

Pulmonary fibroblast migration and differentiation are critical events in fibrogenesis; meanwhile, fibrosis characterizes the pathology of many respiratory diseases. The role of aryl hydrocarbon receptor (AhR), a unique cellular chemical sensor, has been suggested in tissue fibrosis, but the mechanisms through which the AhR-ligand axis influences the fibrotic process remain undefined. In this study, the potential impact of the AhR-ligand axis on pulmonary fibroblast migration and differentiation was analyzed using human primary lung fibroblasts HFL-1 and CCL-202 cells. Boyden chamber-based cell migration assay showed that activated AhR in HFL-1cells significantly enhanced cell migration in response to 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), and a known AhR antagonist, CH223191, inhibited its migratory activity. Furthermore, the calcium mobilization and subsequent upregulated expression of arachidonic acid metabolizing enzymes, including cyclooxygenase2 (COX-2) and 5-lipoxygenase (5-LOX), were observed in TCDD-treated HFL-1 cells, concomitant with elevated levels of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) secretion. Also, significantly increased expression of α-smooth muscle actin α-SMA), a fibroblast differentiation marker, was also noted in TCDD-treated HFL-1 cells (p < 0.05), resulting in a dynamic change in cytoskeleton protein levels and an increase in the nuclear translocation of the myocardin-related transcription factor. Moreover, the enhanced levels of α-SMA expression and fibroblast migration induced by TCDD, PGE2 and LTB4 were abrogated by selective inhibitors for COX-2 and 5-LOX. Knockdown of AhR by siRNA Completely diminished intracellular calcium uptake and reduced α-SMA protein verified by promoter-reporter assays and chromatin immunoprecipitation. Taken together, our results suggested the importance of the AhR-ligand axis in fibroblast migration and differentiation through its capacity in enhancing arachidonic acid metabolism.

Alkylation and arylation of alkenes by transition metal complexes

International Nuclear Information System (INIS)

Volkova, L.G.; Levitin, I.Ya.; Vol'pin, M.E.

1975-01-01

In this paper are reviewed methods of alkylation and irylation of unsaturated compounds with complexes of transition metals (Rh, Pd). Analysis of alkylation and arylation of olefines with organic derivatives of transition metals, obtained as a result of exchange reactions between organic compounds of transition metals and salts of metals of the 8th group of the periodic system, allows a conclusion as to the wide possibilities of these reactions in the synthesis of various derivatives of unsaturated compounds. In all the reactions under consideration, intermediate formation of sigma-complexes is assumed. Also considered are alkylation and arylation of olefines with organic derivatives of halogens in the presence of compounds of metals of the 8th group of the periodic system, as well as arylation of olefines with aromatic compounds in the presence of salts of transition metals

Identification of cinnabarinic acid as a novel endogenous aryl hydrocarbon receptor ligand that drives IL-22 production.

Science.gov (United States)

Lowe, Margaret M; Mold, Jeff E; Kanwar, Bittoo; Huang, Yong; Louie, Alexander; Pollastri, Michael P; Wang, Cuihua; Patel, Gautam; Franks, Diana G; Schlezinger, Jennifer; Sherr, David H; Silverstone, Allen E; Hahn, Mark E; McCune, Joseph M

2014-01-01

The aryl hydrocarbon receptor (AHR) binds to environmental toxicants including synthetic halogenated aromatic hydrocarbons and is involved in a diverse array of biological processes. Recently, the AHR was shown to control host immunity by affecting the balance between inflammatory T cells that produce IL-17 (Th17) and IL-22 versus regulatory T cells (Treg) involved in tolerance. While environmental AHR ligands can mediate this effect, endogenous ligands are likely to be more relevant in host immune responses. We investigated downstream metabolites of tryptophan as potential AHR ligands because (1) tryptophan metabolites have been implicated in regulating the balance between Th17 and Treg cells and (2) many of the AHR ligands identified thus far are derivatives of tryptophan. We characterized the ability of tryptophan metabolites to bind and activate the AHR and to increase IL-22 production in human T cells. We report that the tryptophan metabolite, cinnabarinic acid (CA), is an AHR ligand that stimulates the differentiation of human and mouse T cells producing IL-22. We compare the IL-22-stimulating activity of CA to that of other tryptophan metabolites and define stimulation conditions that lead to CA production from immune cells. Our findings link tryptophan metabolism to AHR activation and define a novel endogenous AHR agonist with potentially broad biological functions.

Visible-light-mediated selective arylation of cysteine in batch and flow

NARCIS (Netherlands)

Bottecchia, C.; Rubens, M.; Gunnoo, S.B.; Hessel, V.; Madder, A.

2017-01-01

A mild visible-light-mediated strategy for cysteine arylation is presented. The method relies on the use of eosin Y as a metal-free photocatalyst and aryldiazonium salts as arylating agents. The reaction can be significantly accelerated in a microflow reactor, whilst allowing the in situ formation

Simultaneous regioselective synthesis of trifluoromethyl-containing 1,7-phenanthrolines and quinolines from cyclocondensation reaction of N,N'-bis(oxotrifluoroalkenyl)-1,3-phenylenediamines

Energy Technology Data Exchange (ETDEWEB)

Bonacorso, Helio G.; Andrighetto, Rosalia; Krueger, Nicolas; Martins, Marcos A.P.; Zanatta, Nilo [Universidade Federal de Santa Maria (NUQUIMHE/UFSM), RS (Brazil). Dept. de Quimica. Nucleo de Quimica de Heterociclos

2011-08-15

This paper reports interesting results of the conventional synthesis of a new series of 2,10-dialkyl(aryl)-4,8-bis(trifluoromethyl)-1,7-phenanthrolines, in 22-40% yields, from cyclization reactions of N,N'-bis(oxotrifluoroalkenyl)-1,3-phenylenediamines [1,3-C{sub 6}H{sub 4}-(NHCR=CHC(O)CF{sub 3}){sub 2}] in a strongly acidic medium and absence of solvent. The synthetic route also allowed the isolation of a new series of 2-alkyl(aryl/heteroaryl)-4-trifluoromethyl-7-aminoquinolines, in 20-73% yields, simultaneously. The enaminone precursors were obtained from the reaction of 4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones [CF{sub 3}C(O)CH=C(R)OR1, where R = H, Me, Ph, 4-MePh, 4-OMePh, 4-ClPh, 4-FPh, 4-BrPh, 4-NO{sub 2}Ph, 2-furyl and R1 = Me, Et] with 1,3-phenylenediamine under mild conditions, in 47-91% yields. (author)

Preparation, Spectroscopic Investigation and Biological Activity of New Mixed Ligand Chelates

International Nuclear Information System (INIS)

Alassbaly, F.S.; Ajaily, M.M.E.

2014-01-01

Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) were studied. The obtained Schiff base and mixed ligand chelates were subjected to several physiochemical techniques, in terms of CHN elemental analyses, molar conductivity, magnetic moment measurements, infrared, proton nuclear magnetic resonance, electronic and mass spectra. The analytical data showed the formation of the Schiff base compound and the ratio of metal to ligands of the chelates are 1:1:1(M:L1:L2). The infrared spectral data exhibited that the used ligands behaving as bidentate ligands towards the metal ions. The proton nuclear magnetic resonance spectral data showed the signals of the active groups in the ligands which entered in chelation with Zn(II) metal ion. The electronic spectral results showed the existence of pie (phenyl ring) and n = pie (C=N) of the ligands and suggested the geometrical structures of the chelates. Meanwhile, the mass spectral data revealed the fragmentations of the Schiff base, anthranilic acid and their Ni(II) mixed ligand chelate has been preformed the only chelate conducted for justification. All the prepared mixed chelates were non-electrolyte in nature. The antibacterial activity of the Schiff base, anthranilic acid, metal salts and mixed ligand chelates were studied and found to be that mixed ligand chelates have the most biological activity in comparison to the free ligands and salts. (author)

Cascade synthesis of dihydrobenzofuran via Claisen rearrangement of allyl aryl ethers using FeCl3/MCM-41 catalyst

Directory of Open Access Journals (Sweden)

Sachin S. Sakate

2018-05-01

Full Text Available Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Brønsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71–86%. Keywords: Claisen rearrangement, Dihydrobenzofuran, Aryl allyl ether, MCM-41, Ferric chloride

Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with tetrahydroxydiboron in water

KAUST Repository

Zernickel, Anna; Du, Weiyuan; Ghorpade, Seema; Sawant, Dinesh Nanaji; Makki, Arwa; Sekar, Nagaiyan; Eppinger, Jö rg

2018-01-01

A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 hours in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.

Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with tetrahydroxydiboron in water

KAUST Repository

Zernickel, Anna

2018-01-09

A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 hours in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.

The use of the 2-aminobenzoic acid tag for oligosaccharide gel electrophoresis.

Science.gov (United States)

Huang, Z; Prickett, T; Potts, M; Helm, R F

2000-08-18

Gel electrophoresis of fluorophore labeled saccharides provides a rapid and reliable method to screen enzymatic and/or chemical treatments of polysaccharides and glycoconjugates, as well as a sensitive and efficient microscale method to separate and purify oligosaccharides for further analysis. A simple and inexpensive method of derivatization and analysis using 2-aminobenzoic acid (anthranilic acid, AA) is described and applied to the extracellular polysaccharide released by the desiccation tolerant cyanobacterium Nostoc commune DRH-1. The results of these analyses suggest a possible protective functionality of two pendent groups, as well as a potential relationship between these groups and the desiccation tolerance of the organism.

Spectroscopic Identification of the Au-C Bond Formation upon Electroreduction of an Aryl Diazonium Salt on Gold.

Science.gov (United States)

Guo, Limin; Ma, Lipo; Zhang, Yelong; Cheng, Xun; Xu, Ye; Wang, Jin; Wang, Erkang; Peng, Zhangquan

2016-11-08

Electroreduction of aryl diazonium salts on gold can produce organic films that are more robust than their analogous self-assembled monolayers formed from chemical adsorption of organic thiols on gold. However, whether the enhanced stability is due to the Au-C bond formation remains debated. In this work, we report the electroreduction of an aryl diazonium salt of 4,4'-disulfanediyldibenzenediazonium on gold forming a multilayer of Au-(Ar-S-S-Ar) n , which can be further degraded to a monolayer of Au-Ar-S - by electrochemical cleavage of the S-S moieties within the multilayer. By conducting an in situ surface-enhanced Raman spectroscopic study of both the multilayer formation/degradation and the monolayer reduction/oxidation processes, coupled to density functional theory calculations, we provide compelling evidence that an Au-C bond does form upon electroreduction of aryl diazonium salts on gold and that the enhanced stability of the electrografted organic films is due to the Au-C bond being intrinsically stronger than the Au-S bond for a given phenylthiolate compound by ca. 0.4 eV.

Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl Hydrazide and Amino Acid-(N'-Nicotinoyl Hydrazide Derivatives

Directory of Open Access Journals (Sweden)

Sherine N. Khattab

2005-09-01

Full Text Available The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl- and N- Boc-amino acid-(N`-nicotinoyl hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl hydrazide hydrochloride salts (7a-7e and amino acid-(N`- nicotinoyl hydrazide hydrochloride salts (8a-8e. These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli.

Structure and luminescent property of complexes of aryl carboxylic acid-functionalized polystyrene with Eu(III) and Tb(III) ions.

Science.gov (United States)

Gao, Baojiao; Shi, Nan; Qiao, Zongwen

2015-11-05

Via polymer reactions, naphthoic acid (NA) and benzoic acid (BA) were bonded onto the side chains of polystyrene (PS), respectively, and two aryl carboxylic acid-functionalized polystyrenes, PSNA and PSBA, were obtained. Using PSNA and PSBA as macromolecule ligands and Eu(3+) and Tb(3+) ions as central ions, various luminescent binary polymer-rare earth complexes were prepared. At the same time, with 1,10-phenanthroline (Phen) and 4,4'-bipyridine (Bipy) as small-molecule co-ligands, various ternary polymer-rare earth complexes were also prepared. On the basis of characterizing PSNA, PSBA and complexes, the relationship between structure and luminescent property for these prepared complexes were mainly investigated. The study results show that the macromolecule ligands PSNA and PSBA, or the bonded NA and BA ligands, can strongly sensitize the fluorescence emissions of Eu(3+) ion or Tb(3+) ion, but the sensitization effect is strongly dependent on the structure of the ligands and the property of the central ions, namely it is strongly dependent on the matching degree of energy levels. The fluorescence emission of the binary complex PS-(NA)3-Eu(III) is stronger than that PS-(BA)3-Eu(III), indicating ligand NA has stronger sensitization action for Eu(3+) ion than ligand BA; the binary complex PS-(BA)3-Tb(III) emit strong characteristic fluorescence of Tb(3+) ion, displaying that ligand BA can strongly sensitize Tb(3+) ion, whereas the binary complex PS-(NA)3-Tb(III) nearly does not emit the characteristic fluorescence of Tb(3+) ion, showing that ligand NA does not sensitize Tb(3+) ion. The fluorescence intensity of the ternary complexes is much stronger than that of the binary complexes in the same series. Copyright © 2015 Elsevier B.V. All rights reserved.

Palladium-catalyzed aryl amination-heck cyclization cascade: A one-flask approach to 3-substituted Indoles

DEFF Research Database (Denmark)

Jensen, Thomas; Pedersen, Henrik; Bang-Andersen, B.

2008-01-01

Two for the price of one: A Pd/dppf-based catalyst provides access to the title compounds from 1,2-dihalogenated aromatic compounds and allylic amines in a single reaction flask. The initial aryl amination step occurs with excellent selectivity for the aryl iodide to ensure the formation of a sin......Two for the price of one: A Pd/dppf-based catalyst provides access to the title compounds from 1,2-dihalogenated aromatic compounds and allylic amines in a single reaction flask. The initial aryl amination step occurs with excellent selectivity for the aryl iodide to ensure the formation...

Synthesis and conformational analysis of new arylated-diphenylurea derivatives related to sorafenib drug via Suzuki-Miyaura cross-coupling reaction

Science.gov (United States)

Al-Masoudi, Najim A.; Essa, Ali Hashem; Alwaaly, Ahmed A. S.; Saeed, Bahjat A.; Langer, Peter

2017-10-01

Sorafenib, is a relatively new cytostatic drug approved for the treatment of renal cell and hepatocellular carcinoma. The development of new sorafenib analogues offers the possibility of generating structures of increased potency. To this end, a series of arylated-diphenylurea analogues 17-31 were synthesized via Suzuki-Miyaura coupling reaction, related to sorafenib by treatment of three diarylureas 2-4 having 3-bromo, 4-chloro and 2-iodo groups with various arylboronic acids. Conformational analysis of the new arylated urea analogues has been investigated using MOPAC 2016 of semi empirical PM7 Hamiltonian computational method. Our results showed that all compounds preferred the trans-trans conformations. Compound 17 has been selected to calculate the torsional energy profiles for rotation around the urea bonds and found to be existed predominantly in the trans-trans conformation with only very minimal fluctuation in conformation.

Identification of cinnabarinic acid as a novel endogenous aryl hydrocarbon receptor ligand that drives IL-22 production.

Directory of Open Access Journals (Sweden)

Margaret M Lowe

Full Text Available The aryl hydrocarbon receptor (AHR binds to environmental toxicants including synthetic halogenated aromatic hydrocarbons and is involved in a diverse array of biological processes. Recently, the AHR was shown to control host immunity by affecting the balance between inflammatory T cells that produce IL-17 (Th17 and IL-22 versus regulatory T cells (Treg involved in tolerance. While environmental AHR ligands can mediate this effect, endogenous ligands are likely to be more relevant in host immune responses. We investigated downstream metabolites of tryptophan as potential AHR ligands because (1 tryptophan metabolites have been implicated in regulating the balance between Th17 and Treg cells and (2 many of the AHR ligands identified thus far are derivatives of tryptophan. We characterized the ability of tryptophan metabolites to bind and activate the AHR and to increase IL-22 production in human T cells. We report that the tryptophan metabolite, cinnabarinic acid (CA, is an AHR ligand that stimulates the differentiation of human and mouse T cells producing IL-22. We compare the IL-22-stimulating activity of CA to that of other tryptophan metabolites and define stimulation conditions that lead to CA production from immune cells. Our findings link tryptophan metabolism to AHR activation and define a novel endogenous AHR agonist with potentially broad biological functions.

Expedient synthesis of C-aryl carbohydrates by consecutive biocatalytic benzoin and aldol reactions.

Science.gov (United States)

Hernández, Karel; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Pohl, Martina; Clapés, Pere

2015-02-16

The introduction of aromatic residues connected by a C-C bond into the non-reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C-aril-sLex). In this work, an expedient asymmetric "de novo" synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the α-hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary D-fructose-6-phosphate aldolase and L-rhamnulose-1-phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphate-dependent aldolases require. In this way, 6-C-aryl-L-sorbose, 6-C-aryl-L-fructose, 6-C-aryl-L-tagatose, and 5-C-aryl-L-xylose derivatives are prepared by using this methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel Reaction of N,N'-Bisarylmethanediamines with Formaldehyde. Synthesis of Some New 1,3,5-Triaryl-1,3,5-hexahydrotriazines

Directory of Open Access Journals (Sweden)

Abolfazl Olyaei

2006-07-01

Full Text Available The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2- pyrazinyl and 4-nitrophenyl methanediamines 5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa- hydrotriazines 6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino- pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded 6a and 6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyldimethylenetriamine (7a as a sole product, which upon subsequent reaction with formaldehyde also afforded 6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.

Synthesis and biological evaluation of novel dioxa-bicycle C-aryl glucosides as SGLT2 inhibitors.

Science.gov (United States)

Yan, Qi; Ding, Ning; Li, Yingxia

2016-02-08

A series of novel C-aryl glucosides containing dioxa-bicycle were synthesized and evaluated for inhibition activity against hSGLT2. Among the compounds tested, compound 6a showed moderate SGLT2 inhibition activities at 700 nM. The results could benefit the discovery of new SGLT2 inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

DEFF Research Database (Denmark)

Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben

2010-01-01

Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...... acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA). The fluorescence of PheSA was efficiently quenched by the HA matrix. HA also acted as a singlet oxygen scavenger. Fluorescence lifetime(s) of PheSA in solution and when attached to the HA matrix has been monitored...

Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

International Nuclear Information System (INIS)

Wang, Yuwei; Meng, Linghui; Fan, Liquan; Ma, Lichun; Qi, Meiwei; Yu, Jiali; Huang, Yudong

2014-01-01

Highlights: • Carbon fibers are grafted with phenyl amine group via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 73%. • Tensile strength of the carbon fibers does not decrease distinctly. • Using water as the reaction medium can avoid pollution from organic solvents. • Grafting via aryl diazonium reaction in one step can improve modification efficiency. - Abstract: Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction “on water” to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction “on water” could be a facile green platform to functionalize carbon fibers for many interesting applications

Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuwei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Liquan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Ma, Lichun; Qi, Meiwei; Yu, Jiali [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

2014-10-15

Highlights: • Carbon fibers are grafted with phenyl amine group via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 73%. • Tensile strength of the carbon fibers does not decrease distinctly. • Using water as the reaction medium can avoid pollution from organic solvents. • Grafting via aryl diazonium reaction in one step can improve modification efficiency. - Abstract: Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction “on water” to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction “on water” could be a facile green platform to functionalize carbon fibers for many interesting applications.

Oxidative addition of aryl chlorides to monoligated palladium(0): A DFT-SCRF study

DEFF Research Database (Denmark)

Ahlquist, Mårten Sten Gösta; Norrby, Per-Ola

2007-01-01

Oxidative addition of aryl chlorides to palladium has been investigated by hybrid density functional theory methods (B3LYP), including a continuum model describing the solvent implicitly. A series of para-substituted aryl chlorides were studied to see the influence of electronic effects...

Rh(I)-Catalyzed Arylation of Heterocycles via C-H Bond Activation: Expanded Scope Through Mechanistic Insight

Energy Technology Data Exchange (ETDEWEB)

Lewis, Jared; Berman, Ashley; Bergman, Robert; Ellman, Jonathan

2007-07-18

A practical, functional group tolerant method for the Rh-catalyzed direct arylation of a variety of pharmaceutically important azoles with aryl bromides is described. Many of the successful azole and aryl bromide coupling partners are not compatible with methods for the direct arylation of heterocycles using Pd(0) or Cu(I) catalysts. The readily prepared, low molecular weight ligand, Z-1-tert-butyl-2,3,6,7-tetrahydrophosphepine, which coordinates to Rh in a bidentate P-olefin fashion to provide a highly active yet thermally stable arylation catalyst, is essential to the success of this method. By using the tetrafluoroborate salt of the corresponding phosphonium, the reactions can be assembled outside of a glove box without purification of reagents or solvent. The reactions are also conducted in THF or dioxane, which greatly simplifies product isolation relative to most other methods for direct arylation of azoles employing high-boiling amide solvents. The reactions are performed with heating in a microwave reactor to obtain excellent product yields in two hours.

A Modular Flow Design for the meta‐Selective C−H Arylation of Anilines

Science.gov (United States)

Gemoets, Hannes P. L.; Laudadio, Gabriele; Verstraete, Kirsten; Hessel, Volker

2017-01-01

Abstract Described herein is an effective and practical modular flow design for the meta‐selective C−H arylation of anilines. The design consists of four continuous‐flow modules (i.e., diaryliodonium salt synthesis, meta‐selective C−H arylation, inline copper extraction, and aniline deprotection) which can be operated either individually or consecutively to provide direct access to meta‐arylated anilines. With a total residence time of 1 hour, the desired product could be obtained in high yield and excellent purity without the need for column chromatography, and the residual copper content meets the standards for parenterally administered pharmaceutical substances. PMID:28543979

Cu-Click Compatible Triazabutadienes To Expand the Scope of Aryl Diazonium Ion Chemistry.

Science.gov (United States)

Cornali, Brandon M; Kimani, Flora W; Jewett, John C

2016-10-07

Triazabutadienes can be used to readily generate reactive aryl diazonium ions under mild, physiologically relevant conditions. These conditions are compatible with a range of functionalities that do not tolerate traditional aryl diazonium ion generation. To increase the utility of this aryl diazonium ion releasing chemistry an alkyne-containing triazabutadiene was synthesized. The copper-catalyzed azide-alkyne cycloaddition ("Cu-click") reaction was utilized to modify the alkyne-containing triazabutadiene and shown to be compatible with the nitrogen-rich triazabutadiene. One of the triazole products was tethered to a fluorophore, thus enabling the direct fluorescent labeling of a model protein.

Evaluating Metabolite-Related DNA Oxidation and Adduct Damage from Aryl Amines Using a Microfluidic ECL Array.

Science.gov (United States)

Bist, Itti; Bhakta, Snehasis; Jiang, Di; Keyes, Tia E; Martin, Aaron; Forster, Robert J; Rusling, James F

2017-11-21

Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and NADPH to oxidize DNA or participate in S N 2 reactions to form covalently linked adducts with DNA bases. Guanines are the main DNA oxidation sites, and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is the initial product. Here we describe a novel electrochemiluminescent (ECL) microwell array that produces metabolites from test compounds and measures relative rates of DNA oxidation and DNA adduct damage. In this new array, films of DNA, metabolic enzymes, and an ECL metallopolymer or complex assembled in microwells on a pyrolytic graphite wafer are housed in dual microfluidic chambers. As reactant solution passes over the wells, metabolites form and can react with DNA in the films to form DNA adducts. These adducts are detected by ECL from a RuPVP polymer that uses DNA as a coreactant. Aryl amines also combine with Cu 2+ and NADPH to form reactive oxygen species (ROS) that oxidize DNA. The resulting 8-oxodG was detected selectively by ECL-generating bis(2,2'-bipyridine)-(4-(1,10-phenanthrolin-6-yl)-benzoic acid)Os(II). DNA/enzyme films on magnetic beads were oxidized similarly, and 8-oxodG determined by LC/MS/MS enabled array standardization. The array limit of detection for oxidation was 720 8-oxodG per 10 6 nucleobases. For a series of aryl amines, metabolite-generated DNA oxidation and adduct formation turnover rates from the array correlated very well with rodent 1/TD 50 and Comet assay results.

Surface modified MXene Ti3C2 multilayers by aryl diazonium salts leading to large-scale delamination

Science.gov (United States)

Wang, Hongbing; Zhang, Jianfeng; Wu, Yuping; Huang, Huajie; Li, Gaiye; Zhang, Xin; Wang, Zhuyin

2016-10-01

Herein we report a simple and facile method to delaminate MXene Ti3C2 multilayers by the assistance of surface modification using aryl diazonium salts. The basic strategy involved the preparation of layered MAX Ti3AlC2 and the exfoliation of Ti3AlC2 into Ti3C2 multilayers, followed by Na+ intercalation and surface modification using sulfanilic acid diazonium salts. The resulting chemically grafted Ti3C2 flakes were characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the presence of the surface organic species. Ultraviolet-visible spectroscopy revealed that surface-modified MXene Ti3C2 sheets disperse well in water and the solutions obey Lambert-Beer's law. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to demonstrate the morphology and structure of delaminating MXene Ti3C2 flakes. The results indicated that chemical modification for MXene multilayers by aryl diazonium salts induced swelling that conversely weakened the bonds between MX layers, hence leading to large-scale delamination of multilayered MXene Ti3C2via mild sonication. Advantages of the present approach rely not only on the simplicity and efficiency of the delamination procedure but also on the grafting of aryl groups to MXene surfaces, highly suitable for further applications of the newly discovered two-dimensional materials.

An Efficient Synthesis of 1-Alkyl-2-phenyl-4-quinolones from 2-Halobenzoic Acids

International Nuclear Information System (INIS)

Song, Yoon Ju; Choi, Jin Sun; Lee, Jae In

2013-01-01

The present method offers an efficient synthesis of 1-alkyl-2-phenyl-4-quinolones from 2-haloben-zoic acids. It has the advantages with respect to (i) synthesis of 2 equiv of alkynones 5 from 1 equiv of 4,6-pyrimidyl di(2-halobenzoates) 3, (ii) synthesis of versatile 1-alkyl-2-phenyl-4-quinolones in high overall yields, and (iii) use of readily available and cheap starting materials. Therefore, this method could be utilized as a practical synthesis of 1-alkyl-2-phenyl-4-quinolones. Several methods have been developed to synthesize 1-alkyl-2-phenyl-4-quinolones from 2'-substituted acetophenones, anilines, and 2-halobenzoyl chlorides as starting materials. The reaction of N-methylisatoic anhydride with the lithium enolate of an 4'-methoxyacetophenone afforded the 1-methyl-2-phenyl-4-quinolone in a short sequence, but the yield was low. N-(2-Acetylphenyl)benzamides, prepared by Friedel-Crafts acylation of N-phenyl benzamides with acetyl chloride or benzoylation of 2'-aminoacetophenones with benzoyl chlorides,8 were cyclized with potassium t-butoxide to yield 2-aryl-4-quinolones, which were further alkylated with alkyl iodides to give 1-alkyl-2-aryl-4-quinolones

An Efficient Synthesis of 1-Alkyl-2-phenyl-4-quinolones from 2-Halobenzoic Acids

Energy Technology Data Exchange (ETDEWEB)

Song, Yoon Ju; Choi, Jin Sun; Lee, Jae In [Duksung Women' s Univ., Seoul (Korea, Republic of)

2013-10-15

The present method offers an efficient synthesis of 1-alkyl-2-phenyl-4-quinolones from 2-haloben-zoic acids. It has the advantages with respect to (i) synthesis of 2 equiv of alkynones 5 from 1 equiv of 4,6-pyrimidyl di(2-halobenzoates) 3, (ii) synthesis of versatile 1-alkyl-2-phenyl-4-quinolones in high overall yields, and (iii) use of readily available and cheap starting materials. Therefore, this method could be utilized as a practical synthesis of 1-alkyl-2-phenyl-4-quinolones. Several methods have been developed to synthesize 1-alkyl-2-phenyl-4-quinolones from 2'-substituted acetophenones, anilines, and 2-halobenzoyl chlorides as starting materials. The reaction of N-methylisatoic anhydride with the lithium enolate of an 4'-methoxyacetophenone afforded the 1-methyl-2-phenyl-4-quinolone in a short sequence, but the yield was low. N-(2-Acetylphenyl)benzamides, prepared by Friedel-Crafts acylation of N-phenyl benzamides with acetyl chloride or benzoylation of 2'-aminoacetophenones with benzoyl chlorides,8 were cyclized with potassium t-butoxide to yield 2-aryl-4-quinolones, which were further alkylated with alkyl iodides to give 1-alkyl-2-aryl-4-quinolones.

Aminoarenethiolato-copper(I) as (pre-)catalyst for the synthesis of diaryl ethers from aryl bromides and sequential C-O/C-S and C-N/C-S cross coupling reactions

NARCIS (Netherlands)

Sperotto, Elena; Klink, Gerard P.M. van; Vries, Johannes G. de; Koten, Gerard van

2010-01-01

A small library of 2-aminoarenethiolato-copper(I) (CuSAr) complexes was tested as (pre-)catalysts in the arylation reaction of phenols with aryl bromides. These copper(I) (pre-)catalysts are thermally stable, soluble in common organic solvents, and allow reactions of 6 h at 160 °C with low catalyst

Catalytic Asymmetric Alkylation of Aryl Heteroaryl Ketones

NARCIS (Netherlands)

Ortiz, Pablo; Harutyunyan, Syuzanna; del Hoyo, Ana

Tertiary diarylmethanols are highly bioactive structural motifs. A new strategy to access chiral tertiary diarylmethanols through copper-catalyzed direct alkylation of (di)(hetero)aryl ketones by using Grignard reagents was developed. The low reactivity and the similarity of the enantiotopic faces

Synthesis of nanodispersible 6-aryl-2,4-diamino-1,3,5-triazine and its derivatives

International Nuclear Information System (INIS)

Padalkar, Vikas S.; Patil, Vikas S.; Phatangare, Kiran R.; Gupta, Vinod D.; Umape, Prashant G.; Sekar, N.

2010-01-01

A series of novel branched derivatives of 6-aryl-2,4-diamino-1,3,5-triazine from corresponding aryl nitriles and dicyanodiamide was synthesized. These compounds show a nanodispersibility and good thermal stability.

A transition-metal-free synthesis of arylcarboxyamides from aryl diazonium salts and isocyanides.

Science.gov (United States)

Xia, Zhonghua; Zhu, Qiang

2013-08-16

A transition-metal-free carboxyamidation process, using aryl diazonium tetrafluoroborates and isocyanides under mild conditions, has been developed. This novel conversion was initiated by a base and solvent induced aryl radical, followed by radical addition to isocyanide and single electron transfer (SET) oxidation, affording the corresponding arylcarboxyamide upon hydration of the nitrilium intermediate.

Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C−O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination

KAUST Repository

Liu, Xiangqian; Hsiao, Chien-Chi; Kalvet, Indrek; Leiendecker, Matthias; Guo, Lin; Schoenebeck, Franziska; Rueping, Magnus

2016-01-01

In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting β-hydride elimination. This new nickel

Cross-Coupling of Sodium Sulfinates with Aryl, Heteroaryl and Vinyl Halides by Nickel/photoredox dual catalysis

KAUST Repository

Yue, Huifeng

2017-12-06

An efficient photoredox/nickel dual catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl and vinyl bromides but also less reactive aryl chlorides are suitable substrates for this transformation.

Cross-Coupling of Sodium Sulfinates with Aryl, Heteroaryl and Vinyl Halides by Nickel/photoredox dual catalysis

KAUST Repository

Yue, Huifeng; Zhu, Chen; Rueping, Magnus

2017-01-01

An efficient photoredox/nickel dual catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl and vinyl bromides but also less reactive aryl chlorides are suitable substrates for this transformation.

Catalytic activity of some oxime-based Pd(II-complexes in Suzuki coupling of aryl and heteroaryl bromides in water

Directory of Open Access Journals (Sweden)

Kamal M. Dawood

2017-05-01

Full Text Available The catalytic activity of four Pd(II-complexes of benzoazole-oximes was extensively studied in Suzuki–Miyaura C–C cross coupling reactions in water, as an eco-friendly green solvent, under both thermal heating as well as microwave irradiation conditions. The cross-coupling reactions included different activated and deactivated aryl- or heteroaryl-bromides with several arylboronic acids. The protected oxime-complexes were found to be more efficient than the free ones.

Aryl hydrocarbon receptor overexpression in miniaturized follicles in female pattern hair loss.

Science.gov (United States)

Ramos, Paulo Müller; Brianezi, Gabrielli; Martins, Ana Carolina Pereira; Silva, Márcia Guimarães da; Marques, Mariângela Esther Alencar; Miot, Hélio Amante

2017-01-01

The etiopathogenesis of female pattern hair loss is still poorly understood. In addition to genetic and hormonal elements, environmental factors could be involved. The aryl hydrocarbon receptor is expressed in keratinocytes and can be activated by environmental pollutants leading to alterations in the cell cycle, inflammation, and apoptosis. Here we demonstrate the overexpression of nuclear aryl hydrocarbon receptors in miniaturized hair follicles in female pattern hair loss.

Effects of varying levels of n-6:n-3 fatty acid ratio on plasma fatty acid ...

African Journals Online (AJOL)

This study investigated the effects of varying dietary levels of n-6:n-3 fatty acid ratio on plasma fatty acid composition and prostanoid synthesis in pregnant rats. Four groups consisting of seven rats per group of non pregnant rats were fed diets with either a very low n-6:n-3 ratio of 50% soybean oil (SBO): 50% cod liver oil ...

Aryl sulfonate based anticancer alkylating agents.

Science.gov (United States)

Sheikh, Hamdullah Khadim; Arshad, Tanzila; Kanwal, Ghazala

2018-05-01

This research work revolves around synthesis of antineoplastic alkylating sulfonate esters with dual alkylating sites for crosslinking of the DNA strands. These molecules were evaluated as potential antineoplastic cross linking alkylating agents by reaction with the nucleoside of Guanine DNA nucleobase at both ends of the synthesized molecule. Synthesis of the alkylating molecules and the crosslinking with the guanosine nucleoside was monitored by MALDITOF mass spectroscopy. The synthesized molecule's crosslinking or adduct forming rate with the nucleoside was compared with that of 1,4 butane disulfonate (busulfan), in form of time taken for the appearance of [M+H] + . It was found that aryl sulfonate leaving group was causing higher rate of nucleophilic attack by the Lewis basic site of the nucleobase. Furthermore, the rate was also found to be a function of electron withdrawing or donating nature of the substituent on the aryl ring. Compound with strong electron withdrawing substituent on the para position of the ring reacted fastest. Hence, new alkylating agents were synthesized with optimized or desired reactivity.

Radioiodination via isotope exchange in pivalic acid

International Nuclear Information System (INIS)

Weichert, J.P.; Van Dort, M.E.; Groziak, M.P.; Counsell, R.E.

1986-01-01

A variety of benzoic and aryl aliphatic mono and polyiodinated acids and esters (sterol, triglyceride) were radioiodinated in 55-99% radiochemical yield by isotope exchange with Na 125 i in a melt of pivalic acid. In general, the reaction was complete in 1 h at 155 0 C with little or no substrate decomposition. High specific activity studies afforded 125 I-labeled iopanoic acid with a specific activity of over 700 Ci/mmol. (author)

A Modular Flow Design for the meta-Selective C-H Arylation of Anilines.

Science.gov (United States)

Gemoets, Hannes P L; Laudadio, Gabriele; Verstraete, Kirsten; Hessel, Volker; Noël, Timothy

2017-06-12

Described herein is an effective and practical modular flow design for the meta-selective C-H arylation of anilines. The design consists of four continuous-flow modules (i.e., diaryliodonium salt synthesis, meta-selective C-H arylation, inline copper extraction, and aniline deprotection) which can be operated either individually or consecutively to provide direct access to meta-arylated anilines. With a total residence time of 1 hour, the desired product could be obtained in high yield and excellent purity without the need for column chromatography, and the residual copper content meets the standards for parenterally administered pharmaceutical substances. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Indolyl aryl sulfones (IASs): development of highly potent NNRTIs active against wt-HIV-1 and clinically relevant drug resistant mutants.

Science.gov (United States)

Silvestri, Romano; Artico, Marino

2005-01-01

Indolyl aryl sulfones (IASs) are a potent class of NNRTIs developed from L-737,126, a lead agent discovered by Merck AG. IAS derivatives are endowed with inhibitory activities against wt HIV-1 in the low nanomolar concentration range. Introduction of two methyl groups at positions 3 and 5 of the phenyl ring of the aryl sulfonyl moiety furnished IAS derivatives such as 5-chloro- or 5-bromo-3-[(3,5-dimethylphenyl)sulfonyl]indole-2-carboxyamide, which showed very potent and selective anti-HIV-1 activity against some mutants carrying NNRTI resistant mutations at positions 103 and 181 of the reverse transcriptase. IAS derivatives bearing 2-hydroxyethylcarboxyamide or 2-hydroxyethylcarboxyhydrazide groups at position 2 of the indole nucleus were more active than L-737,126 against the K103N-Y181C double mutant. A great improvement of antiviral activity against wt HIV-1 and resistant mutants was obtained by coupling 1-3 simple amino acids, such as glycine and alanine, in sequence, with the 3-[(3,5-dimethylphenyl)sulfonyl]-1H-indole-2-carbonyl moiety. The transformation of the chain terminus into amide or hydrazide, produced short peptides with high selectivity and potent activity against wt HIV-1, and the viral mutants Y181C, K103N-Y181C and EFV(R). IAS having two halogen atoms at the indole showed potent inhibitory activity against the Y181C and the EFV(R) resistant mutant strains. In particular, the introduction of a fluorine atom at position 4 of the indole ring notably contributed to improve the antiviral activities against both wt and the related resistant mutants. 5-Nitro-IASs were highly active against wt HIV-1 and exhibited low cytotoxicity. Experimental data highlighted the class IAS derivatives as promising candidates for clinical trials.

Toxicity of copper chelates of azomethines and amino acids for Chlorella pyrenoidosa

Energy Technology Data Exchange (ETDEWEB)

Barashkov, G.K.; Rukhadze, E.G.; Talyzenkova, G.P.

1979-01-01

The authors have attempted to assess the toxicity of copper-containing compounds from the point of view of their interrelationship with the structural characteristics of the chelate compound and the structure of the ligand. The copper chelates of the azomethines tested may be provisionally divided into three types: A - complexes with N-alkly-azomethines; B - complexes with N-aryl-azomethines; C - binuclear complexes. Consideration was also given to chelates with aromatic and heterocyclic amino acids and to heteroligand chelates in which the copper atom coordinates azomethine and an amino acid simultaneously. Toxicity was determined by the method previously described and expressed as a critical concentration (C/sub cr/, mg Cu/liter) and in relative toxicity units (T/sub c/). The compounds investigated were obtained from the interaction between a bidentant ligand of an azomethine or anamino acid and copper acetate in a water-alcohol medium at pH 6-8. Since they are not very soluble in water, true solutions were obtained by using dimethyl sulfoxide.

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: a Review

Science.gov (United States)

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-04-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article.

An Electron-Transporting Thiazole-Based Polymer Synthesized Through Direct (Hetero)Arylation Polymerization.

Science.gov (United States)

Chávez, Patricia; Bulut, Ibrahim; Fall, Sadiara; Ibraikulov, Olzhas A; Chochos, Christos L; Bartringer, Jérémy; Heiser, Thomas; Lévêque, Patrick; Leclerc, Nicolas

2018-05-25

In this work, a new n -type polymer based on a thiazole-diketopyrrolopyrrole unit has been synthesized through direct (hetero)arylation polycondensation. The molar mass has been optimized by systematic variation of the the monomer concentration. Optical and electrochemical properties have been studied. They clearly suggested that this polymer possess a high electron affinity together with a very interesting absorption band, making it a good non-fullerene acceptor candidate. As a consequence, its charge transport and photovoltaic properties in a blend with the usual P3HT electron-donating polymer have been investigated.

Reactivity of Aryl Halides for Reductive Dehalogenation in (Seawater Using Polymer-Supported Terpyridine Palladium Catalyst

Directory of Open Access Journals (Sweden)

Toshimasa Suzuka

2015-05-01

Full Text Available A polymer-supported terpyridine palladium complex was prepared. The complex was found to promote hydrodechlorination of aryl chlorides with potassium formate in seawater. Generally, reductive cleavage of aryl chlorides using transition metal catalysts is more difficult than that of aryl bromides and iodides (reactivity: I > Br > Cl; however, the results obtained did not follow the general trend. Therefore, we investigated the reaction inhibition agents and found a method to remove these inhibitors. The polymeric catalysts showed high catalytic activity and high reusability for transfer reduction in seawater.

Lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan as a new strategy for oral delivery of insulin: in vitro, ex vivo and in vivo characterizations.

Science.gov (United States)

Mahjub, Reza; Radmehr, Moojan; Dorkoosh, Farid Abedin; Ostad, Seyed Naser; Rafiee-Tehrani, Morteza

2014-12-01

The purpose of this research was the development, in vitro, ex vivo and in vivo characterization of lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan. Insulin nanoparticles were prepared from methylated N-(4-N,N-dimethylaminobenzyl), methylated N-(4 pyridinyl) and methylated N-(benzyl). Insulin nanoparticles containing non-modified chitosan and also trimethyl chiotsan (TMC) were also prepared as control. The effects of the freeze-drying process on physico-chemical properties of nanoparticles were investigated. The release of insulin from the nanoparticles was studied in vitro. The mechanism of the release of insulin from different types of nanoparticles was determined using curve fitting. The secondary structure of the insulin released from the nanoparticles was analyzed using circular dichroism and the cell cytotoxicity of nanoparticles on a Caco-2 cell line was determined. Ex vivo studies were performed on excised rat jejunum using Frantz diffusion cells. In vivo studies were performed on diabetic male Wistar rats and blood glucose level and insulin serum concentration were determined. Optimized nanoparticles with proper physico-chemical properties were obtained. The lyophilization process was found to cause a decrease in zeta potential and an increase in PdI as well as and a decrease in entrapment efficiency (EE%) and loading efficiency (LE%) but conservation in size of nanoparticles. Atomic force microscopy (AFM) images showed non-aggregated, stable and spherical to sub-spherical nanoparticles. The in vitro release study revealed higher release rates for lyophilized compared to non-lyophilized nanoparticles. Cytotoxicity studies on Caco-2 cells revealed no significant cytotoxicity for prepared nanoparticles after 3-h post-incubation but did show the concentration-dependent cytotoxicity after 24 h. The percentage of cumulative insulin determined from ex vivo studies was significantly higher in nanoparticles prepared

Formation of an adduct by clenbuterol, a beta-adrenoceptor agonist drug, and serum albumin in human saliva at the acidic pH of the stomach: evidence for an aryl radical-based process.

Science.gov (United States)

Pietraforte, D; Brambilla, G; Camerini, S; Scorza, G; Peri, L; Loizzo, A; Crescenzi, M; Minetti, M

2008-07-15

Clenbuterol (CLB) is an antiasthmatic drug used also illegally as a lean muscle mass enhancer in both humans and animals. CLB and amine-related drugs in general are nitrosatable, thus raising concerns regarding possible genotoxic/carcinogenic activity. Oral administration of CLB raises the issue of its possible transformation by salivary nitrite at the acidic pH of gastric juice. In acidic human saliva CLB was rapidly transformed to the CLB arenediazonium ion. This suggests a reaction of CLB with salivary nitrite, as confirmed in aerobic HNO(2) solution by a drastic decrease in nitric oxide, nitrite, and nitrate. In human saliva, both glutathione and ascorbic acid were able to inhibit CLB arenediazonium formation and to react with preformed CLB arenediazonium. The effect of ascorbic acid is particularly pertinent because this vitamin is actively concentrated within the gastric juice. EPR spin trapping experiments showed that preformed CLB arenediazonium ion was reduced to the aryl radical by ascorbic acid, glutathione, and serum albumin, the major protein of saliva. As demonstrated by anti-CLB antibodies and MS, the CLB-albumin interaction leads to the formation of a covalent drug-protein adduct, with a preference for Tyr-rich regions. This study highlights the possible hazards associated with the use/abuse of this drug.

Eco-friendly synthesis, in vitro anti-proliferative evaluation, and 3D-QSAR analysis of a novel series of monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates.

Science.gov (United States)

Racané, Livio; Ptiček, Lucija; Sedić, Mirela; Grbčić, Petra; Kraljević Pavelić, Sandra; Bertoša, Branimir; Sović, Irena; Karminski-Zamola, Grace

2018-04-17

Herein, we describe the synthesis of twenty-one novel water-soluble monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates 3a-3u and present the results of their anti-proliferative assays. Efficient syntheses were achieved by three complementary simple two-step synthetic protocols based on the condensation reaction of aryl/heteroaryl carbaldehydes or carboxylic acid. We developed an eco-friendly synthetic protocol using glycerol as green solvent, particularly appropriate for the condensation of thermally and acid-sensitive heterocycles such as furan, benzofuran, pyrrole, and indole. Screening of anti-proliferative activity was performed on four human tumour cell lines in vitro including pancreatic cancer (CFPAC-1), metastatic colon cancer (SW620), hepatocellular carcinoma (HepG2), and cervical cancer (HeLa), as well as in normal human fibroblast cell lines. All tested compounds showed strong to moderate anti-proliferative activity on tested cell lines depending on the structure containing aryl/heteroaryl moiety coupled to 6-(2-imidazolinyl)benzothiazole moiety. The most potent cytostatic effects on all tested cell lines with [Formula: see text] values ranging from 0.1 to 3.70 [Formula: see text] were observed for benzothiazoles substituted with naphthalene-2-yl 3c, benzofuran-2-yl 3e, indole-3-yl 3j, indole-2-yl 3k, quinoline-2-yl 3s, and quinoline-3-yl 3t and derivatives substituted with phenyl 3a, naphthalene-1-yl 3b, benzothiazole-2-yl 3g, benzothiazole-6-yl 3h, N-methylindole-3-yl 3l, benzimidazole-2-yl 3n, benzimidazole-5(6)-yl 3o, and quinolone-4-yl 3u with [Formula: see text] values ranging from 1.1 to 29.1 [Formula: see text]. Based on obtained anti-proliferative activities, 3D-QSAR models for five cell lines were derived. Molecular volume, molecular surface, the sum of hydrophobic surface areas, molecular mass, and possibility of making dispersion forces were identified by QSAR analyses as molecular properties that are

Electronic absorption spectral studies of Pr(III) chelates with some amino acids

Science.gov (United States)

Kachhawa, Chanchal; Solanki, Kanika; Bhandari, H. S.

2018-05-01

Investigations on Pr(III) systems with 1:1 metal-ligand stoichiometric ratio have been carried out in different solvents. β - Alanine, Taurine and anthranilic acid have been opted as ligands for the investigations. The Study is based on doped crystal phenomenon. The Slater-Condon, spin-orbit, nephelauxetic, bonding, Racah and Judd-Ofelt parameters have been explored during the study. Four bands for Pr(III) have been observed and recorded in the region 350 nm to 900nm. Partial regression method has been used for calculations. Use of computational chemistry has been explored in order to develop better and easier methods of calculations.

Conformationally constrained dipeptide surrogates with aromatic side-chains: synthesis of 4-aryl indolizidin-9-one amino acids by conjugate addition to a common alpha,omega-diaminoazelate enone intermediate.

Science.gov (United States)

Cluzeau, Jérôme; Lubell, William D

2004-03-05

Four methyl 9-oxo-8-(N-(Boc)-amino)-4-phenyl-1-azabicyclo[4.3.0]nonane carboxylates (11, 4-Ph-I(9)aa-OMe) were synthesized from (2S,8S,5E)-di-tert-butyl-4-oxo-5-ene-2,8-bis[N-(PhF)amino]azelate [(5E)-7, PhF = 9-(9-phenylfluorenyl)] via a seven-step process featuring a conjugate addition/reductive amination/lactam cyclization sequence. Various nucleophiles were used in the conjugate addition reactions on enone (5E)-7 as a general route for making alpha,omega-diaminoazelates possessing different substituents in good yield albeit low diastereoselectivity except in the case of aryl Grignard reagents (9/1 to 15/1 drs). 6-Phenylazelates (6S)-8d and (6R)-8d were separated by chromatography and diastereoselective precipitation and independently transformed into 4-Ph-I(9)aa-OMe. From (6S)-8d, (2S,4R,6R,8S)-4-Ph-I(9)aa-OMe 11 was prepared selectively in 51% yield. Reductive amination of (6R)-8d provided the desired pipecolates 9 along with desamino compound 10, which was minimized by performing the hydrogenation in the presence of ammonium acetate. Subsequent ester exchange, lactam cyclization, and amine protection provided three products (2R,4S,6S,8R)-, (2R,4S,6S,8S)-, and (2S,4S,6R,8S)-4-Ph-I(9)aa-OMe 11 in 10, 6, and 6% yields, respectively, from (6R)-8d. Ester hydrolysis of (2S,4R,6R,8S)-11 furnished 4-phenyl indolizidin-9-one N-(Boc)amino acid 3 as a novel constrained Ala-Phe dipeptide surrogate for studying conformation-activity relationships of biologically active peptides.

Analysis of diverse direct arylation polymerization (DArP) conditions toward the efficient synthesis of polymers converging with stille polymers in organic solar cells

DEFF Research Database (Denmark)

Livi, Francesco; Gobalasingham, Nemal S.; Thompson, Barry C.

2016-01-01

Despite the emergence of direct arylation polymerization (DArP) as an alternative method to traditional cross-coupling routes like Stille polymerization, the exploration of DArP polymers in practical applications like polymer solar cells (PSCs) is limited. DArP polymers tend to have a reputation...... for being marginally inferior to Stille counterparts due to the increased presence of defects that result from unwanted side reactions in direct arylation, such as unselective C-H bond activation and homocoupling. We report ten DArP protocols across the three major classes of DArP to generate poly[(2,5-bis...... was synthesized in superheated THF with Cs2CO3, neodecanoic acid, and P(o-anisyl)3, it generated polymers of exceptional quality that performed comparably to Stille counterparts in both roll coated ITO-free and spin-coated ITO devices....

Cooperative Magnetism in Crystalline N-Aryl-Substituted Verdazyl Radicals: First-Principles Predictions and Experimental Results.

Science.gov (United States)

Eusterwiemann, Steffen; Dresselhaus, Thomas; Doerenkamp, Carsten; Janka, Oliver; Niehaus, Oliver; Massolle, Anja; Daniliuc, Constantin G; Eckert, Hellmut; Pöttgen, Rainer; Neugebauer, Johannes; Studer, Armido

2017-05-02

We report on a series of eight diaryl-6-oxo-verdazyl radicals containing a tert-butyl group at the C(3) position with regard to their crystal structure and magnetic properties by means of magnetic susceptibility measurements in combination with quantum chemical calculations using a first-principles bottom-up approach. The latter method allows for a qualitative prediction and detailed analysis of the correlation between the solid-state architecture and magnetic properties. Although the perturbation in the molecular structure by varying the substituent on the N-aryl ring may appear small, the effects upon the structural parameters controlling intermolecular magnetic coupling interactions are strong, resulting in a wide spectrum of cooperative magnetic behavior. The non-substituted 1,5-diphenyl-tert-butyl-6-oxo-verdazyl radical features a ferromagnetic one-dimensional spin ladder type magnetic network-an extremely rarely observed phenomenon for verdazyl radicals. By varying substituents at the phenyl group, different non-isostructural compounds were obtained with widely different magnetic motifs ranging from linear and zigzag one-dimensional chains to potentially two-dimensional networks, from which we predict magnetic susceptibility data that are in qualitative agreement with experiments and reveal a large sensitivity to packing effects of the molecules. The present study advances the fundamental understanding between solid-state structure and magnetism in organically based radical systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Nootropic and Neuroprotective Features of Aryl-Substituted Analogs of Gamma-Aminobutyric Acid.

Science.gov (United States)

Tyurenkov, I N; Borodkina, L E; Bagmetova, V V; Berestovitskaya, V M; Vasil'eva, O S

2016-02-01

GABA analogs containing phenyl (phenibut) or para-chlorophenyl (baclofen) substituents demonstrated nootropic activity in a dose of 20 mg/kg: they improved passive avoidance conditioning, decelerated its natural extinction, and exerted antiamnestic effect on the models of amnesia provoked by scopolamine or electroshock. Tolyl-containing GABA analog (tolibut, 20 mg/kg) exhibited antiamnestic activity only on the model of electroshock-induced amnesia. Baclofen and, to a lesser extent, tolibut alleviated seizures provoked by electroshock, i.e. both agents exerted anticonvulsant effect. All examined GABA aryl derivatives demonstrated neuroprotective properties on the maximum electroshock model: they shortened the duration of coma and shortened the period of spontaneous motor activity recovery. In addition, these agents decreased the severity of passive avoidance amnesia and behavioral deficit in the open field test in rats exposed to electroshock. The greatest neuroprotective properties were exhibited by phenyl-containing GABA analog phenibut.

Docosahexaenoic acid and n-6 docosapentaenoic acid supplementation alter rat skeletal muscle fatty acid composition

Directory of Open Access Journals (Sweden)

Lim Sun-Young

2007-04-01

Full Text Available Abstract Background Docosahexaenoic acid (22:6n-3, DHA and n-6 docosapentaenoic acid (22:5n-6, DPAn-6 are highly unsaturated fatty acids (HUFA, ≥ 20 carbons, ≥ 3 double bonds that differ by a single carbon-carbon double bond at the Δ19 position. Membrane 22:6n-3 may support skeletal muscle function through optimal ion pump activity of sarcoplasmic reticulum and electron transport in the mitochondria. Typically n-3 fatty acid deficient feeding trials utilize linoleic acid (18:2n-6, LA as a comparison group, possibly introducing a lower level of HUFA in addition to n-3 fatty acid deficiency. The use of 22:5n-6 as a dietary control is ideal for determining specific requirements for 22:6n-3 in various physiological processes. The incorporation of dietary 22:5n-6 into rat skeletal muscles has not been demonstrated previously. A one generation, artificial rearing model was utilized to supply 22:6n-3 and/or 22:5n-6 to rats from d2 after birth to adulthood. An n-3 fatty acid deficient, artificial milk with 18:2n-6 was supplemented with 22:6n-3 and/or 22:5n-6 resulting in four artificially reared (AR dietary groups; AR-LA, AR-DHA, AR-DPAn-6, AR-DHA+DPAn-6. A dam reared group (DAM was included as an additional control. Animals were sacrificed at 15 wks and soleus, white gastrocnemius and red gastrocnemius muscles were collected for fatty acid analyses. Results In all muscles of the DAM group, the concentration of 22:5n-6 was significantly lower than 22:6n-3 concentrations. While 22:5n-6 was elevated in the AR-LA group and the AR-DPAn-6 group, 20:4n-6 tended to be higher in the AR-LA muscles and not in the AR-DPAn-6 muscles. The AR-DHA+DPAn-6 had a slight, but non-significant increase in 22:5n-6 content. In the red gastrocnemius of the AR-DPAn-6 group, 22:5n-6 levels (8.1 ± 2.8 wt. % did not reciprocally replace the 22:6n-3 levels observed in AR-DHA reared rats (12.2 ± 2.3 wt. % suggesting a specific preference/requirement for 22:6n-3 in red

Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

Science.gov (United States)

Wang, Yuwei; Meng, Linghui; Fan, Liquan; Ma, Lichun; Qi, Meiwei; Yu, Jiali; Huang, Yudong

2014-10-01

Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction "on water" to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction "on water" could be a facile green platform to functionalize carbon fibers for many interesting applications.

Internal rotation of 1-Aryl-3,3-dialkyltriazenes. Comparison of semiempirical molecular orbital calculations with far-infrared, Raman, and NMR spectroscopic results

International Nuclear Information System (INIS)

Panitz, J.C.; Lippert, T.; Wokaun, A.

1994-01-01

PM3 and AM1 semiempirical molecular orbital techniques are used to establish a model for internal rotation about the N 2 -N 3 axis of 1-aryl-3,3-dialkyltriazines. The PM3 method is satisfactory for obtaining agreement between the experimental and calculated results, but the AM1 method has an artifact in the potential energy curve of internal rotation about the N 2 -N 3 axis. 24 refs., 6 figs., 5 tabs

Copper-Catalyzed Synthesis of Mixed Alkyl Aryl Phosphonates

NARCIS (Netherlands)

Fañanás-Mastral, Martín; Feringa, Ben L

2014-01-01

Copper-catalysis allows the direct oxygenarylation of dialkyl phosphonates with diaryliodonium salts. This novel methodology proceeds with a wide range of phosphonates and phosphoramidates under mild conditions and gives straightforward access to valuable mixed alkyl aryl phosphonates in very good

Substrate promiscuity of a rosmarinic acid synthase from lavender (Lavandula angustifolia L.).

Science.gov (United States)

Landmann, Christian; Hücherig, Stefanie; Fink, Barbara; Hoffmann, Thomas; Dittlein, Daniela; Coiner, Heather A; Schwab, Wilfried

2011-08-01

One of the most common types of modification of secondary metabolites is the acylation of oxygen- and nitrogen-containing substrates to produce esters and amides, respectively. Among the known acyltransferases, the members of the plant BAHD family are capable of acylating a wide variety of substrates. Two full-length acyltransferase cDNAs (LaAT1 and 2) were isolated from lavender flowers (Lavandula angustifolia L.) by reverse transcriptase-PCR using degenerate primers based on BAHD sequences. Recombinant LaAT1 exhibited a broad substrate tolerance accepting (hydroxy)cinnamoyl-CoAs as acyl donors and not only tyramine, tryptamine, phenylethylamine and anthranilic acid but also shikimic acid and 4-hydroxyphenyllactic acid as acceptors. Thus, LaLT1 forms esters and amides like its phylogenetic neighbors. In planta LaAT1 might be involved in the biosynthesis of rosmarinic acid, the ester of caffeic acid and 3,4-dihydroxyphenyllactic acid, a major constituent of lavender flowers. LaAT2 is one of three members of clade VI with unknown function.

Complexes of uranium (IV) and thorium (IV) with α-picolinic acid, nicotinic acid, anthranilic acid and N-phenylanthranilic acid

International Nuclear Information System (INIS)

Singh, M.; Singh, R.

1979-01-01

Stable U(IV) and Th(IV) complexes with the title ligands have been synthesised from U(OAc) 4 , and Th(OAc) 4 . Magnetic susceptibilities, IR and reflectance spectra of U(IV) and IR spectra of Th(IV) complexes have been studied which indicate eight coordination for U(IV) in these chelates. (auth.)

Microsomal aryl hydrocarbon hydroxylase comparison of the direct, indirect and radiometric assays

International Nuclear Information System (INIS)

Denison, M.S.; Murray, M.; Wilkinson, C.F.

1983-01-01

The direct fluorometric assay of aryl hydrocarbon hydroxlyase has been compared to the more commonly used indirect fluorometric and radiometric assays. Although rat hepatic microsomal activities measured by the direct assay were consistently higher than those obtained by the other assays, the relative changes in activity following enzyme induction and/or inhibition were similar. The direct assay provides an accurate and rapid measure of aryl hydrocarbon hydroxylase activity and avoids several problems inherent in the indirect and radiometric assays. 2 tables

Amino acid chirality breaking by N-phosphorylation

International Nuclear Information System (INIS)

Zhao Yufen; Yan Qingjin.

1995-01-01

The chirality breaking of amino acid is a focus issue in the origin of life. For chemists, there are some interesting chemical approaches to solve the symmetry breaking problem. Our previous experiments indicated that when amino acids were phosphorylated, there were many bio-mimic reactions happened. In this paper, it was found that there had significant difference between the N-phosphoryl L- and D- amino acids such as serine and threonine. The optical rotation tracing experiments of the racemic N-phosphoamino acids also showed the similar results. The chirality breaking of amino acids by N-phosphorylation was a novel phenomena. (author). 3 refs, 1 fig. Abstract only

Protein resistance of surfaces modified with oligo(ethylene glycol) aryl diazonium derivatives.

Science.gov (United States)

Fairman, Callie; Ginges, Joshua Z; Lowe, Stuart B; Gooding, J Justin

2013-07-22

Anti-fouling surfaces are of great importance for reducing background interference in biosensor signals. Oligo(ethylene glycol) (OEG) moieties are commonly used to confer protein resistance on gold, silicon and carbon surfaces. Herein, we report the modification of surfaces using electrochemical deposition of OEG aryl diazonium salts. Using electrochemical and contact angle measurements, the ligand packing density is found to be loose, which supports the findings of the fluorescent protein labelling that aryl diazonium OEGs confer resistance to nonspecific adsorption of proteins albeit lower than alkane thiol-terminated OEGs. In addition to protein resistance, aryl diazonium attachment chemistry results in stable modification. In common with OEG species on gold electrodes, OEGs with distal hydroxyl moieties do confer superior protein resistance to those with a distal methoxy group. This is especially the case for longer derivatives where superior coiling of the OEG chains is possible. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interaction of (n-3) and (n-6) fatty acids in desaturation and chain elongation of essential fatty acids in cultured glioma cells

International Nuclear Information System (INIS)

Cook, H.W.; Spence, M.W.

1987-01-01

Recent research in various biological systems has revived interest in interactions between the (n-6) and (n-3) essential fatty acids. We have utilized cultured glioma cells to show that linolenic acid, 18:3(n-3), is rapidly desaturated and chain elongated; 20:5(n-3) is the major product and accumulates almost exclusively in phospholipids. We examined effects of various (n-6), (n-3), (n-9) and (n-7) fatty acids at 40 microM concentration on desaturation and chain elongation processes using [1- 14 C]18:3(n-3) as substrate. In general, monoenoic fatty acids were without effect. The (n-6) fatty acids (18:2, 18:3, 20:3, 20:4 and 22:4) had little effect on total product formed. There was a shift of labeled product to triacylglycerol, and in phospholipids, slightly enhanced conversion of 20:5 to 22:5 was evident. In contrast, 22:6(n-3) was inhibitory, whereas 20:3(n-3) and 20:5(n-3) had much less effect. At concentrations less than 75 microM, all acids were inhibitory. Most products were esterified to phosphatidylcholine, but phosphatidylethanolamine also contained a major portion of 20:5 and 22:5. We provide a condensed overview of how the (n-6) and (n-3) fatty acids interact to modify relative rates of desaturation and chain elongation, depending on the essential fatty acid precursor. Thus, the balance between these dietary acids can markedly influence enzymes providing crucial membrane components and substrates for biologically active oxygenated derivatives

Dietary (n-6 : n-3 Fatty Acids Alter Plasma and Tissue Fatty Acid Composition in Pregnant Sprague Dawley Rats

Directory of Open Access Journals (Sweden)

Amira Abdulbari Kassem

2012-01-01

Full Text Available The objective of this paper is to study the effects of varying dietary levels of n-6 : n-3 fatty acid ratio on plasma and tissue fatty acid composition in rat. The treatment groups included control rats fed chow diet only, rats fed 50% soybean oil (SBO: 50% cod liver oil (CLO (1 : 1, 84% SBO: 16% CLO (6 : 1, 96% SBO: 4% CLO (30 : 1. Blood samples were taken at day 15 of pregnancy, and the plasma and tissue were analyzed for fatty acid profile. The n-3 PUFA in plasma of Diet 1 : 1 group was significantly higher than the other diet groups, while the total n-6 PUFA in plasma was significantly higher in Diet 30 : 1 group as compared to the control and Diet 1 : 1 groups. The Diet 1 : 1 group showed significantly greater percentages of total n-3 PUFA and docosahexaenoic acid in adipose and liver tissue, and this clearly reflected the contribution of n-3 fatty acids from CLO. The total n-6 PUFA, linoleic acid, and arachidonic acid were significantly difference in Diet 30 : 1 as compared to Diet 1 : 1 and control group. These results demonstrated that the dietary ratio of n-6 : n-3 fatty acid ratio significantly affected plasma and tissue fatty acids profile in pregnant rat.

Dietary (n-6 : n-3) fatty acids alter plasma and tissue fatty acid composition in pregnant Sprague Dawley rats.

Science.gov (United States)

Kassem, Amira Abdulbari; Abu Bakar, Md Zuki; Yong Meng, Goh; Mustapha, Noordin Mohamed

2012-01-01

The objective of this paper is to study the effects of varying dietary levels of n-6 : n-3 fatty acid ratio on plasma and tissue fatty acid composition in rat. The treatment groups included control rats fed chow diet only, rats fed 50% soybean oil (SBO): 50% cod liver oil (CLO) (1 : 1), 84% SBO: 16% CLO (6 : 1), 96% SBO: 4% CLO (30 : 1). Blood samples were taken at day 15 of pregnancy, and the plasma and tissue were analyzed for fatty acid profile. The n-3 PUFA in plasma of Diet 1 : 1 group was significantly higher than the other diet groups, while the total n-6 PUFA in plasma was significantly higher in Diet 30 : 1 group as compared to the control and Diet 1 : 1 groups. The Diet 1 : 1 group showed significantly greater percentages of total n-3 PUFA and docosahexaenoic acid in adipose and liver tissue, and this clearly reflected the contribution of n-3 fatty acids from CLO. The total n-6 PUFA, linoleic acid, and arachidonic acid were significantly difference in Diet 30 : 1 as compared to Diet 1 : 1 and control group. These results demonstrated that the dietary ratio of n-6 : n-3 fatty acid ratio significantly affected plasma and tissue fatty acids profile in pregnant rat.

Dietary (n-6 : n-3) Fatty Acids Alter Plasma and Tissue Fatty Acid Composition in Pregnant Sprague Dawley Rats

Science.gov (United States)

Kassem, Amira Abdulbari; Abu Bakar, Md Zuki; Yong Meng, Goh; Mustapha, Noordin Mohamed

2012-01-01

The objective of this paper is to study the effects of varying dietary levels of n-6 : n-3 fatty acid ratio on plasma and tissue fatty acid composition in rat. The treatment groups included control rats fed chow diet only, rats fed 50% soybean oil (SBO): 50% cod liver oil (CLO) (1 : 1), 84% SBO: 16% CLO (6 : 1), 96% SBO: 4% CLO (30 : 1). Blood samples were taken at day 15 of pregnancy, and the plasma and tissue were analyzed for fatty acid profile. The n-3 PUFA in plasma of Diet 1 : 1 group was significantly higher than the other diet groups, while the total n-6 PUFA in plasma was significantly higher in Diet 30 : 1 group as compared to the control and Diet 1 : 1 groups. The Diet 1 : 1 group showed significantly greater percentages of total n-3 PUFA and docosahexaenoic acid in adipose and liver tissue, and this clearly reflected the contribution of n-3 fatty acids from CLO. The total n-6 PUFA, linoleic acid, and arachidonic acid were significantly difference in Diet 30 : 1 as compared to Diet 1 : 1 and control group. These results demonstrated that the dietary ratio of n-6 : n-3 fatty acid ratio significantly affected plasma and tissue fatty acids profile in pregnant rat. PMID:22489205

Antioxidant Functions of the Aryl Hydrocarbon Receptor

Directory of Open Access Journals (Sweden)

Cornelia Dietrich

2016-01-01

Full Text Available The aryl hydrocarbon receptor (AhR is a transcription factor belonging to the basic helix-loop-helix/PER-ARNT-SIM family. It is activated by a variety of ligands, such as environmental contaminants like polycyclic aromatic hydrocarbons or dioxins, but also by naturally occurring compounds and endogenous ligands. Binding of the ligand leads to dimerization of the AhR with aryl hydrocarbon receptor nuclear translocator (ARNT and transcriptional activation of several xenobiotic phase I and phase II metabolizing enzymes. It is generally accepted that the toxic responses of polycyclic aromatic hydrocarbons, dioxins, and structurally related compounds are mediated by activation of the AhR. A multitude of studies indicate that the AhR operates beyond xenobiotic metabolism and exerts pleiotropic functions. Increasing evidence points to a protective role of the AhR against carcinogenesis and oxidative stress. Herein, I will highlight data demonstrating a causal role of the AhR in the antioxidant response and present novel findings on potential AhR-mediated antioxidative mechanisms.

Serum n-3 Tetracosapentaenoic Acid and Tetracosahexaenoic Acid Increase Following Higher Dietary α-Linolenic Acid but not Docosahexaenoic Acid.

Science.gov (United States)

Metherel, Adam H; Domenichiello, Anthony F; Kitson, Alex P; Lin, Yu-Hong; Bazinet, Richard P

2017-02-01

n-3 Tetracosapentaenoic acid (24:5n-3, TPAn-3) and tetracosahexaenoic acid (24:6n-3, THA) are believed to be important intermediates to docosahexaenoic acid (DHA, 22:6n-3) synthesis. The purpose of this study is to report for the first time serum concentrations of TPAn-3 and THA and their response to changing dietary α-linolenic acid (18:3n-3, ALA) and DHA. The responses will then be used in an attempt to predict the location of these fatty acids in relation to DHA in the biosynthetic pathway. Male Long Evans rats (n = 6 per group) were fed either a low (0.1% of total fatty acids), medium (3%) or high (10%) ALA diet with no added DHA, or a low (0%), medium (0.2%) or high (2%) DHA diet with a background of 2% ALA for 8 weeks post-weaning. Serum n-3 and n-6 polyunsaturated fatty acid (PUFA) concentrations (nmol/mL ± SEM) were determined by gas chromatography-mass spectrometry. Serum THA increases from low (0.3 ± 0.1) to medium (5.8 ± 0.7) but not from medium to high (4.6 ± 0.9) dietary ALA, while serum TPAn-3 increases with increasing dietary ALA from 0.09 ± 0.04 to 0.70 ± 0.09 to 1.23 ± 0.14 nmol/mL. Following DHA feeding, neither TPAn-3 or THA change across all dietary DHA intake levels. Serum TPAn-3 demonstrates a similar response to dietary DHA. In conclusion, this is the first study to demonstrate that increases in dietary ALA but not DHA increase serum TPAn-3 and THA in rats, suggesting that both fatty acids are precursors to DHA in the biosynthetic pathway.

Cobalt-promoted regioselective preparation of aryl tetrazole amines

Indian Academy of Sciences (India)

KONDRAGANTI LAKSHMI

2018-04-17

Apr 17, 2018 ... To the best of .... coupled product with aryl iodide under mild reaction ..... Having the optimal conditions studied, the scope of ... ity, environmental acceptability and cost-effectiveness ... lite as a new and reusable heterogeneous catalyst Chem. ... Aminotetrazoles from Thioureas: A Strategy for Diver-.

PEG1000-Based Dicationic Acidic Ionic Liquid Catalyzed One-Pot Synthesis of 4-Aryl-3-Methyl-1-Phenyl-1H-Benzo[h]pyrazolo [3,4-b]quinoline-5,10-Diones via Multicomponent Reactions

Directory of Open Access Journals (Sweden)

Yi-Ming Ren

2015-09-01

Full Text Available A novel and green approach for efficient and rapid synthesis of 4-aryl-3-methyl-1-phenyl-1H-benzo[h]pyrazolo[3,4-b]quinoline-5,10-diones has been accomplished by the one-pot condensation reaction of aromatic aldehydes, 3-methyl-1-phenyl-1H-pyrazol-5-amine and 2-hydroxynaphthalene-1,4-dione using PEG1000-based dicationic acidic ionic liquid (PEG1000-DAIL as a catalyst was reported. Recycling studies have shown that the PEG1000-DAIL can be readily recovered and reused several times without significant loss of activity. The key advantages are the short reaction time, high yields, simple workup, and recovered catalyst.

Structural transformations on N-acetylneuraminic acid

International Nuclear Information System (INIS)

Schmid, W.

1986-01-01

Structural transformations on N-Acetylneuraminic acid are of special interest because of the biological importance of this compound. Although many stereo- and regioselective variations (especially for pyranoid derivatives) have been reported, no detailed studies of the furanoid derivatives from N-Acetylneuramino-1, 4-lactone diethyl dithioacetal have been described hitherto. Therefore a series of derivatives of the Neu5Ac-lactone diethyl dithioacetal has been investigated by n.m.r. spectroscopic techniques. The complete assignment of the 1 H and 13 C resonances was achieved by relaxation time measurements, decoupling experiments and 2-D - shiftcorrelation spectroscopy. The influence of different substituents on the conformational behavior is also discussed. For the Tetra-O-Acetyl-N-acetylneuraminic acid-γ-lactone diethyl dithioacetal the conformation in solution could be determined. The observed data were explained by a zigzag conformation of the backbone as described for the acetylated mannose diethyl dithioacetal. The synthesis of the tetrazole-analogue of N-Acetylneuraminic acid is also described. This compound is of special biological interest because there is a similarity in acidity between the carboxyl-group and the tetrazole-function and the metabolic stability of the tetrazole function is enhanced in comparison with the carboxyl-group. Many of the biological functions of N-Acetylneuraminic acid are connected with the presence of the carboxyl-group. It was therefore interesting to transform this group to the bioisostere tetrazole-function to investigate the influence of the tetrazole-group of this compound on biological activity in the future. During the application of protective groups in the field of Neuraminic acid chemistry a new compound, an ortholactone-derivative of Neu5Ac, was discovered. It's structure is similar to an adamantanecage and the chemistry of such an orthoester function opens new possibilities for structural transformations on N

Using supramolecular binding motifs to provide precise control over the ratio and distribution of species in multiple component films grafted on surfaces: demonstration using electrochemical assembly from aryl diazonium salts.

Science.gov (United States)

Gui, Alicia L; Yau, Hon Man; Thomas, Donald S; Chockalingam, Muthukumar; Harper, Jason B; Gooding, J Justin

2013-04-16

Supramolecular interactions between two surface modification species are explored to control the ratio and distribution of these species on the resultant surface. A binary mixture of aryl diazonium salts bearing oppositely charged para-substituents (either -SO3(-) or -N(+)(Me)3), which also reduce at different potentials, has been examined on glassy carbon surfaces using cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). Striking features were observed: (1) the two aryl diazonium salts in the mixed solution undergo reductive adsorption at the same potential which is distinctively less negative than the potential required for the reduction of either of the two aryl diazonium salts alone; (2) the surface ratio of the two phenyl derivatives is consistently 1:1 regardless of the ratio of the two aryl diazonium salts in the modification solutions. Homogeneous distribution of the two oppositely charged phenyl species on the modified surface has also been suggested by XPS survey spectra. Diffusion coefficient measurements by DOSY NMR and DFT based computation have indicated the association of the two aryl diazonium species in the solution, which has led to changes in the molecular orbital energies of the two species. This study highlights the potential of using intermolecular interactions to control the assembly of multicomponent thin layers.

Novel quinazoline ring synthesis by cycloaddition of N-arylketenimines with N,N-disubstituted cyanamides.

Science.gov (United States)

Shimizu, Masao; Oishi, Akihiro; Taguchi, Yoichi; Gama, Yasuo; Shibuya, Isao

2002-03-01

The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C=N-CN under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C=N-substituted quinazoline derivatives, respectively. These products were formed by [4+2] cycloaddition between the aza-diene moieties of the N-arylsubstituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline derivative was synthesized by hydrolysis of the latter product.

Synthesis of Quinolines through Three-Component Cascade Annulation of Aryl Diazonium Salts, Nitriles, and Alkynes.

Science.gov (United States)

Wang, Hao; Xu, Qian; Shen, Sheng; Yu, Shouyun

2017-01-06

An efficient and rapid synthesis of multiply substituted quinolines is described. This method is enabled by a three-component cascade annulation of readily available aryl diazonium salts, nitriles, and alkynes. This reaction is catalyst- and additive-free. Various aryl diazonium salts, nitriles, and alkynes can participate in this transformation, and the yields are up to 83%.

Docking and 3-D QSAR studies on indolyl aryl sulfones. Binding mode exploration at the HIV-1 reverse transcriptase non-nucleoside binding site and design of highly active N-(2-hydroxyethyl)carboxamide and N-(2-hydroxyethyl)carbohydrazide derivatives.

Science.gov (United States)

Ragno, Rino; Artico, Marino; De Martino, Gabriella; La Regina, Giuseppe; Coluccia, Antonio; Di Pasquali, Alessandra; Silvestri, Romano

2005-01-13

Three-dimensional quantitative structure-activity relationship (3-D QSAR) studies and docking simulations were developed on indolyl aryl sulfones (IASs), a class of novel HIV-1 non-nucleoside reverse transcriptase (RT) inhibitors (Silvestri, et al. J. Med. Chem. 2003, 46, 2482-2493) highly active against wild type and some clinically relevant resistant strains (Y181C, the double mutant K103N-Y181C, and the K103R-V179D-P225H strain, highly resistant to efavirenz). Predictive 3-D QSAR models using the combination of GRID and GOLPE programs were obtained using a receptor-based alignment by means of docking IASs into the non-nucleoside binding site (NNBS) of RT. The derived 3-D QSAR models showed conventional correlation (r(2)) and cross-validated (q(2)) coefficients values ranging from 0.79 to 0.93 and from 0.59 to 0.84, respectively. All described models were validated by an external test set compiled from previously reported pyrryl aryl sulfones (Artico, et al. J. Med. Chem. 1996, 39, 522-530). The most predictive 3-D QSAR model was then used to predict the activity of novel untested IASs. The synthesis of six designed derivatives (prediction set) allowed disclosure of new IASs endowed with high anti-HIV-1 activities.

Dissociation and homoconjugation equilibria of some acids and bases in N,N-dimethylformamide.

Science.gov (United States)

Roletto, E; Vanni, A

1977-01-01

The following monoprotic acids have been studied in N,N-dimethylformamide (DMF): p-toluenesulphonic acid; 2,6-dichlorobenzoic acid; 2,5-dichlorophenol; the anilinium ion; the N-methyl-anilinium ion. The first dissociation step of malonic and succinic acids has also been studied. Dissociation and homoconjugation constants have been determined potentiometrically, at 25 degrees , in buffer solutions containing either the acid and its tetraethylammonium salt or the base and its picrate. Homoconjugation equilibria between unchanged acid and univalent conjugate base have been found not only for benzoic acid and phenol derivatives, but also between undissociated diprotic carboxylic acids and the corresponding monoanions, which are strongly intramolecularly hydrogen-bonded. Results are discussed with reference to previously published values.

C-Aryl glucoside SGLT2 inhibitors containing a biphenyl motif as potential anti-diabetic agents.

Science.gov (United States)

Ding, Yuyang; Mao, Liufeng; Xu, Dengfeng; Xie, Hui; Yang, Ling; Xu, Hongjiang; Geng, Wenjun; Gao, Yong; Xia, Chunguang; Zhang, Xiquan; Meng, Qingyi; Wu, Donghai; Zhao, Junling; Hu, Wenhui

2015-07-15

A series of highly active C-aryl glucoside SGLT2 inhibitors containing a biphenyl motif were designed and synthesized for biological evaluation. Among the compounds tested, compound 16l demonstrated high inhibitory activity against SGLT2 (IC50=1.9 nM) with an excellent pharmacokinetic profile. Further study indicated that the in vivo efficacy of compound 16l was comparable to that of dapagliflozin, suggesting that further development would be worthwhile. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oxidative electrochemical aryl C-C coupling of spiropyrans

NARCIS (Netherlands)

Ivashenko, Oleksii; van Herpt, Jochem T.; Rudolf, Petra; Feringa, Ben L.; Browne, Wesley R.

2013-01-01

The isolation and definitive assignment of the species formed upon electrochemical oxidation of nitro-spiropyran (SP) is reported. The oxidative aryl C-C coupling at the indoline moiety of the SP radical cation to form covalent dimers of the ring-closed SP form is demonstrated. The coupling is

Thermodynamic properties of donor-acceptor complexes of tertiary amine with aryl ketones in hexane medium

Energy Technology Data Exchange (ETDEWEB)

Kumar, R. [Department of Physics, The New College, Chennai 600 014 (India); Jayakumar, S. [Department of Physics, R.K.M. Vivekananda College, Chennai 600 004 (India); Kannappan, V., E-mail: vkannappan@hotmail.com [Department of Chemistry, Presidency College, Chennai 600 005 (India)

2012-05-20

Highlights: Black-Right-Pointing-Pointer Ultrasonic scan is carried out on ternary systems of aromatic tertiary amine and three aryl ketones. Black-Right-Pointing-Pointer Formation of CT complexes is found between tertiary amine with aryl ketones. Black-Right-Pointing-Pointer Stability constant values are computed by ultrasonic and spectral methods are compared. Black-Right-Pointing-Pointer The trend in the 'K' suggests that substituents in ketones influence the stabilities of these complexes. Black-Right-Pointing-Pointer The thermodynamic parameters suggest CT interaction is exothermic and the complexes are thermodynamically stable. - The thermodynamic stability of complexes formed between N,N-dimethylaniline (DMANI) and three ketones, namely, acetophenone (ACP), 4-chloroactophenone (ClACP) and 4-methylacetophenone (MACP) in n-hexane is extensively investigated by spectral and ultrasonic methods. The ultrasound scan was carried out in the temperature range 208.15-313.15 K and at atmospheric pressure on solutions containing equimolar concentrations of components ranging from 0.025 to 0.2 M. The existence of solute-solute interactions has also been confirmed through electronic absorption spectra analyzed with Benesi-Hildebrand theory at 303.15 K. The stability constants of the donor-acceptor complexes determined both by spectroscopic and ultrasonic methods are comparable and follow similar trends. The trend in the formation constants is discussed with structures of the components. The thermodynamic behavior of the systems was explained through the computed values of the free energy ({Delta}G), enthalpy ({Delta}H) and entropy ({Delta}S) changes for complex formation are computed and discussed.

Selective Hydrogen Atom Abstraction through Induced Bond Polarization: Direct α-Arylation of Alcohols through Photoredox, HAT, and Nickel Catalysis.

Science.gov (United States)

Twilton, Jack; Christensen, Melodie; DiRocco, Daniel A; Ruck, Rebecca T; Davies, Ian W; MacMillan, David W C

2018-05-04

The combination of nickel metallaphotoredox catalysis, hydrogen atom transfer catalysis, and a Lewis acid activation mode, has led to the development of an arylation method for the selective functionalization of alcohol α-hydroxy C-H bonds. This approach employs zinc-mediated alcohol deprotonation to activate α-hydroxy C-H bonds while simultaneously suppressing C-O bond formation by inhibiting the formation of nickel alkoxide species. The use of Zn-based Lewis acids also deactivates other hydridic bonds such as α-amino and α-oxy C-H bonds. This approach facilitates rapid access to benzylic alcohols, an important motif in drug discovery. A 3-step synthesis of the drug Prozac exemplifies the utility of this new method. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxidation of ortho- and para-aminobenzoic acid. A pulse radiolysis- and gamma radiolysis study

International Nuclear Information System (INIS)

Solar, Sonja; Getoff, Nikola; Zona, Robert; Solar, Wolfgang

2011-01-01

The oxidation of anthranilic acid (ortho-aminobenzoic acid, ANA) and para-aminobenzoic acid (PABA) by · OH, N 3 · and O ·- in basic solution was studied by pulse radiolysis. The kinetic and spectroscopic characteristics of the intermediate transients were determined. For ANA the site attack of the OH radicals was established to be ∼50% on the -NH 2 moiety and ∼50% on the aromatic ring with an overall rate constant k( · OH+ANA)=(5.5x10 9 ) dm 3 mol -1 s -1 . The rate constant of PABA was k( · OH+PABA)=8x10 9 dm 3 mol -1 s -1 . The OH-adducts of both compounds showed a first order decay of 0.8x10 5 and 1.2x10 5 s -1 , respectively, whereby the corresponding anilino-radicals were formed. The rate constant of ANA with solvated electrons was k(e - aq +ANA)=2.9x10 9 dm 3 mol -1 s -1 . The radiation induced decomposition of both substrates was studied by gamma radiolysis as a function of the absorbed dose. They exhibited a distinct radiation resistance, the initial degradation yields were ∼0.16 μmol J -1 , i.e. only 28% of the · OH radicals contributed to their decomposition. The hydroxylation process was of minor importance, the yield of hydroxylated aminobenzoic acids was≤0.01 μmol J -1 .

Small scale affinity purification and high sensitivity reversed phase nanoLC-MS N-glycan characterization of mAbs and fusion proteins.

Science.gov (United States)

Higel, Fabian; Seidl, Andreas; Demelbauer, Uwe; Sörgel, Fritz; Frieß, Wolfgang

2014-01-01

N-glycosylation is a complex post-translational modification with potential effects on the efficacy and safety of therapeutic proteins and known influence on the effector function of biopharmaceutical monoclonal antibodies (mAbs). Comprehensive characterization of N-glycosylation is therefore important in biopharmaceutical development. In early development, e.g. during pool or clone selection, however, only minute protein amounts of multiple samples are available for analytics. High sensitivity and high throughput methods are thus needed. An approach based on 96-well plate sample preparation and nanoLC-MS of 2- anthranilic acid or 2-aminobenzoic acid (AA) labeled N-glycans for the characterization of biopharmaceuticals in early development is reported here. With this approach, 192 samples can be processed simultaneously from complex matrices (e.g., cell culture supernatant) to purified 2-AA glycans, which are then analyzed by reversed phase nanoLC-MS. Attomolar sensitivity has been achieved by use of nanoelectrospray ionization, resulting in detailed glycan maps of mAbs and fusion proteins that are exemplarily shown in this work. Reproducibility, robustness and linearity of the approach are demonstrated, making use in a routine manner during pool or clone selection possible. Other potential fields of application, such as glycan biomarker discovery from serum samples, are also presented.

Deciphering the Origin, Evolution, and Physiological Function of the Subtelomeric Aryl-Alcohol Dehydrogenase Gene Family in the Yeast Saccharomyces cerevisiae.

Science.gov (United States)

Yang, Dong-Dong; de Billerbeck, Gustavo M; Zhang, Jin-Jing; Rosenzweig, Frank; Francois, Jean-Marie

2018-01-01

Homology searches indicate that Saccharomyces cerevisiae strain BY4741 contains seven redundant genes that encode putative aryl-alcohol dehydrogenases (AAD). Yeast AAD genes are located in subtelomeric regions of different chromosomes, and their functional role(s) remain enigmatic. Here, we show that two of these genes, AAD4 and AAD14 , encode functional enzymes that reduce aliphatic and aryl-aldehydes concomitant with the oxidation of cofactor NADPH, and that Aad4p and Aad14p exhibit different substrate preference patterns. Other yeast AAD genes are undergoing pseudogenization. The 5' sequence of AAD15 has been deleted from the genome. Repair of an AAD3 missense mutation at the catalytically essential Tyr 73 residue did not result in a functional enzyme. However, ancestral-state reconstruction by fusing Aad6 with Aad16 and by N-terminal repair of Aad10 restores NADPH-dependent aryl-alcohol dehydrogenase activities. Phylogenetic analysis indicates that AAD genes are narrowly distributed in wood-saprophyte fungi and in yeast that occupy lignocellulosic niches. Because yeast AAD genes exhibit activity on veratraldehyde, cinnamaldehyde, and vanillin, they could serve to detoxify aryl-aldehydes released during lignin degradation. However, none of these compounds induce yeast AAD gene expression, and Aad activities do not relieve aryl-aldehyde growth inhibition. Our data suggest an ancestral role for AAD genes in lignin degradation that is degenerating as a result of yeast's domestication and use in brewing, baking, and other industrial applications. IMPORTANCE Functional characterization of hypothetical genes remains one of the chief tasks of the postgenomic era. Although the first Saccharomyces cerevisiae genome sequence was published over 20 years ago, 22% of its estimated 6,603 open reading frames (ORFs) remain unverified. One outstanding example of this category of genes is the enigmatic seven-member AAD family. Here, we demonstrate that proteins encoded by two

Cellulose sulphuric acid as a biodegradable catalyst for conversion ...

Indian Academy of Sciences (India)

This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been ...

Effect of Enriched Feed by n-3 fatty acids and 2% of n-6 fatty acid on Danio rerio Reproduction

Directory of Open Access Journals (Sweden)

N.B.P Utomo

2007-07-01

Full Text Available This experiment was conducted to determine the optimum n-3 fatty acid level in the diet containing 2 % of n-6 fatty acid on the reproductive performance of zebra fish (Danio rerio. There experimental diets containing 0.0; 1.0; 1.5 % n-3 fatty acid with 2.0 % n-6 fatty acid was fed to the fish, three times daily, at satiation, for two months. In order to evaluate the gonadal development of the broodstock, two gonads og fish was used for histologis preparation in every 7 days. At the end of the second month, reproductive performance was evaluated through parameters of gonad somato indeks, fecundity, fertilization rate, hatching rate, yolk egg absorbtion rate, survival rate of 3 days old larvae. Sample of fish also was taken for proximate composition as the end of this experiment. Results shows that at the fifth weeks of this experiment, gonad of fish fed on 1.0 % of n-3 fatty acid and 2.0 % n-6 fatty acid already produce eggs with the some size, while others. Still produce small size of eggs. It was found also that the whole body of fish fed an diet with 1.0% n-3 fatty acid contain the highest protein level compare to two other diets. Based on the evaluation of reproduction performance parameters, it was concluded that the optimum dietary level of n-3 fatty acid with 2.0 % n-6 fatty acid for Danio rerio was 0.81 - 0.90 %. Keywords: essential fatty, acids, reproduction, zebra fish, Danio rerio   ABSTRAK Penelitian ini bertujuan untuk menentukan kadar asam lemak n-3 optimum dalam pakan yang mempunyai kadar asam lemak n-6 tetap. Tiga macam pakan dengan kadar asam lemak n-3 berbeda yaitu 0.0; 1.0; dan 2.0 % diberikan pada ikan dengan bobot rata-rata 0.12 g. Pakan diberikan secara at satiation, 4 kali sehari selama 60 hari. Setiap 7 hari sekali diambil sampel ikan untuk pembentukan preparat histologi gonad dengan tujuan untuk mengevaluasi perkembangan gonad. Pada akhir penelitian, induk dipijahkan dan dievaluasi performan reproduksi berdasarkan

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.

One-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents

OpenAIRE

Sloan, Nikki L.; Luthra, Sajinder K.; McRobbie, Graeme; Pimlott, Sally L.; Sutherland, Andrew

2017-01-01

An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125I-labelled aryl compounds and SPECT radiotracers.

The isolation and mapping of a novel hydroxycinnamoyltransferase in the globe artichoke chlorogenic acid pathway

Directory of Open Access Journals (Sweden)

Bourgaud Frédéric

2009-03-01

Full Text Available Abstract Background The leaves of globe artichoke and cultivated cardoon (Cynara cardunculus L. have significant pharmaceutical properties, which mainly result from their high content of polyphenolic compounds such as monocaffeoylquinic and dicaffeoylquinic acid (DCQ, and a range of flavonoid compounds. Results Hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase (HQT encoding genes have been isolated from both globe artichoke and cultivated cardoon (GenBank accessions DQ915589 and DQ915590, respectively using CODEHOP and PCR-RACE. A phylogenetic analysis revealed that their sequences belong to one of the major acyltransferase groups (anthranilate N-hydroxycinnamoyl/benzoyltransferase. The heterologous expression of globe artichoke HQT in E. coli showed that this enzyme can catalyze the esterification of quinic acid with caffeoyl-CoA or p-coumaroyl-CoA to generate, respectively, chlorogenic acid (CGA and p-coumaroyl quinate. Real time PCR experiments demonstrated an increase in the expression level of HQT in UV-C treated leaves, and established a correlation between the synthesis of phenolic acids and protection against damage due to abiotic stress. The HQT gene, together with a gene encoding hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyltransferase (HCT previously isolated from globe artichoke, have been incorporated within the developing globe artichoke linkage maps. Conclusion A novel acyltransferase involved in the biosynthesis of CGA in globe artichoke has been isolated, characterized and mapped. This is a good basis for our effort to understand the genetic basis of phenylpropanoid (PP biosynthesis in C. cardunculus.

The isolation and mapping of a novel hydroxycinnamoyltransferase in the globe artichoke chlorogenic acid pathway

Science.gov (United States)

Comino, Cinzia; Hehn, Alain; Moglia, Andrea; Menin, Barbara; Bourgaud, Frédéric; Lanteri, Sergio; Portis, Ezio

2009-01-01

Background The leaves of globe artichoke and cultivated cardoon (Cynara cardunculus L.) have significant pharmaceutical properties, which mainly result from their high content of polyphenolic compounds such as monocaffeoylquinic and dicaffeoylquinic acid (DCQ), and a range of flavonoid compounds. Results Hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase (HQT) encoding genes have been isolated from both globe artichoke and cultivated cardoon (GenBank accessions DQ915589 and DQ915590, respectively) using CODEHOP and PCR-RACE. A phylogenetic analysis revealed that their sequences belong to one of the major acyltransferase groups (anthranilate N-hydroxycinnamoyl/benzoyltransferase). The heterologous expression of globe artichoke HQT in E. coli showed that this enzyme can catalyze the esterification of quinic acid with caffeoyl-CoA or p-coumaroyl-CoA to generate, respectively, chlorogenic acid (CGA) and p-coumaroyl quinate. Real time PCR experiments demonstrated an increase in the expression level of HQT in UV-C treated leaves, and established a correlation between the synthesis of phenolic acids and protection against damage due to abiotic stress. The HQT gene, together with a gene encoding hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyltransferase (HCT) previously isolated from globe artichoke, have been incorporated within the developing globe artichoke linkage maps. Conclusion A novel acyltransferase involved in the biosynthesis of CGA in globe artichoke has been isolated, characterized and mapped. This is a good basis for our effort to understand the genetic basis of phenylpropanoid (PP) biosynthesis in C. cardunculus. PMID:19292932

Quantitation of alpha-linolenic acid elongation to eicosapentaenoic and docosahexaenoic acid as affected by the ratio of n6/n3 fatty acids

Directory of Open Access Journals (Sweden)

Somoza Veronika

2009-02-01

Full Text Available Abstract Background Conversion of linoleic acid (LA and alpha-linolenic acid (ALA to their higher chain homologues in humans depends on the ratio of ingested n6 and n3 fatty acids. Design and methods In order to determine the most effective ratio with regard to the conversion of ALA to eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA, human hepatoma cells were incubated with varying ratios of [13C] labeled linoleic acid ([13C]LA- and alpha-linolenic acid ([13C]ALA-methylesters. Regulative cellular signal transduction pathways involved were studied by determinations of transcript levels of the genes encoding delta-5 desaturase (D5D and delta-6 desaturase (D6D, peroxisome proliferator-activated receptor alpha (PPARα and sterol regulatory element binding protein 1c (SREBP-1c. Mitogen-activated protein kinase kinase 1 (MEK1 and mitogen-activated protein kinase kinase kinase 1 (MEKK1 were also examined. Results Maximum conversion was observed in cells incubated with the mixture of [13C]LA/[13C]ALA at a ratio of 1:1, where 0.7% and 17% of the recovered [13C]ALA was converted to DHA and EPA, respectively. Furthermore, differential regulation of enzymes involved in the conversion at the transcript level, dependent on the ratio of administered n6 to n3 fatty acids in human hepatocytes was demonstrated. Conclusion Formation of EPA and DHA was highest at an administered LA/ALA ratio of 1:1, although gene expression of PPARα, SREBP-1c and D5D involved in ALA elongation were higher in the presence of ALA solely. Also, our findings suggest that a diet-induced enhancement of the cell membrane content of highly unsaturated fatty acids is only possible up to a certain level.

Chemical modification of carbon powders with aminophenyl and aryl-aliphatic amine groups by reduction of in situ generated diazonium cations: Applicability of the grafted powder towards CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Aurelie Grondein; Daniel Belanger [Universite du Quebec a Montreal, Montreal, PQ (Canada). Departement de Chimie

2011-08-15

Aminophenyl, p-aminobenzyl and p-aminoethylphenyl groups were grafted at the surface of carbon Vulcan XC72R by spontaneous reduction of the in situ generated diazonium cations from the corresponding amine. X-ray photoelectron spectroscopy and elemental analysis confirmed an amine loading of about 1 mmol/g. The grafting of amine functionalities leads to a decrease of specific surface area from 223 to about 110 m{sup 2}/g with a drastic loss of microporosity. Acid-base properties of the surface are also affected by the modification. Aminophenyl grafted groups make the surface more acidic while aryl-aliphatic amines groups tends to render it more basic. The grafted layer shows in each case a good thermal stability up to 250{sup o}C. The affinity of the modified powder towards CO{sub 2} and N{sub 2} has been evaluated by thermal swing adsorption. The maximum adsorption capacity of CO{sub 2} of modified carbons is lower than the unmodified carbon but the presence of the amine functionalities involves a better selectivity of the material towards CO{sub 2} adsorption in comparison of N{sub 2} adsorption. 53 refs., 9 figs., 3 tabs.

ESI(+-MS and GC-MS Study of the Hydrolysis of N-Azobenzyl Derivatives of Chitosan

Directory of Open Access Journals (Sweden)

Fernanda S. Pereira

2014-10-01

Full Text Available New N-p-chloro-, N-p-bromo-, and N-p-nitrophenylazobenzylchitosan derivatives, as well as the corresponding azophenyl and azophenyl-p-sulfonic acids, were synthesized by coupling N-benzylvchitosan with aryl diazonium salts. The synthesized molecules were analyzed by UV-Vis, FT-IR, 1H-NMR and 15N-NMR spectroscopy. The capacity of copper chelation by these materials was studied by AAS. Chitosan and the derivatives were subjected to hydrolysis and the products were analyzed by ESI(+-MS and GC-MS, confirming the formation of N-benzyl chitosan. Furthermore, the MS results indicate that a nucleophilic aromatic substitution (SnAr reaction occurs under hydrolysis conditions, yielding chloroaniline from N-p-bromo-, and N-p-nitrophenylazo-benzylchitosan as well as bromoaniline from N-p-chloro-, and N-p-nitrophenylazobenzyl-chitosan.

The effect of n-6/n-3 fatty acid ratios on broiler breeder performance, hatchability, fatty acid profile and reproduction.

Science.gov (United States)

Khatibjoo, A; Kermanshahi, H; Golian, A; Zaghari, M

2018-04-20

This experiment was conducted to study the effect of dietary omega6 (n-6) to omega3 (n-3) fatty acid (FA) ratios on performance and reproduction of broiler breeders. In experiment 1, 400 females and 40 males (30 week age) of Ross 308 broiler breeder (20 females and two males in each pen) were randomly assigned to one of the four diets with n-6/n-3 FA ratios of 4, 6, 8 and 16 (control). As a measure of hatchability, fertility of eggs and general incubation traits, 1,200 eggs (60 eggs from each pen) were collected and incubated for 21 days and embryo liver and brain fatty acid profile in 14 and 21 days were determined. In experiment 2, 48 males (three males in each pen) randomly assigned to one of the four diets with n-6/n-3 FA ratios of 4, 6, 8 and 16 (control). Semen was collected twice weekly, and semen volume, spermatozoa concentration and motility and alive and dead spermatozoa were estimated. Egg production and egg mass were decreased by n-6/n-3 FA ratios of 4:1 and 6:1 (p n-3 of egg yolk, semen, testis and liver and brain of embryo and day-old chicken were increased while concentration of linoleic acid, arachidonic acid and docosatetraenoic acid of mentioned tissues were decreased by increasing n-6/n-3 FA ratios (p > .05). In conclusion, absolute amount of n-3 and n-6 FAs in broiler breeder diet may be more important than n-6/n-3 FA ratios and to consider reproductive and performance traits of breeders, it is necessary to supply higher levels of n-3 and n-6 FA with respect to n-6/n-3 FA ratios. © 2018 Blackwell Verlag GmbH.

Synthesis of sulfadiazinyl acyl/aryl thiourea derivatives as calf intestinal alkaline phosphatase inhibitors, pharmacokinetic properties, lead optimization, Lineweaver-Burk plot evaluation and binding analysis.

Science.gov (United States)

Sajid-Ur-Rehman; Saeed, Aamer; Saddique, Gufran; Ali Channar, Pervaiz; Ali Larik, Fayaz; Abbas, Qamar; Hassan, Mubashir; Raza, Hussain; Fattah, Tanzeela Abdul; Seo, Sung-Yum

2018-06-02

To seek the new medicinal potential of sulfadiazine drug, the free amino group of sulfadiazine was exploited to obtain acyl/aryl thioureas using simple and straightforward protocol. Acyl/aryl thioureas are well recognized bioactive pharmacophore containing moieties. A new series (4a-4j) of sulfadiazine derived acyl/aryl thioureas was synthesized and characterized through spectroscopic and elemental analysis. The synthesized derivatives 4a-4j were subjected to calf intestinal alkaline phosphatase (CIAP) activity. The derivative 4a-4j showed better inhibition potential compared to standard monopotassium phosphate (MKP). The compound 4c exhibited higher potential in the series with IC 50 0.251 ± 0.012 µM (standard KH 2 PO 4 4.317 ± 0.201 µM). Lineweaver-Burk plots revealed that most potent derivative 4c inhibition CIAP via mixed type pathway. Pharmacological investigations showed that synthesized compounds 4a-4j obey Lipinsk's rule. ADMET parameters evaluation predicted that these molecule show significant lead like properties with minimum possible toxicity and can serve as templates in drug designing. The synthetic compounds show none mutagenic and irritant behavior. Molecular docking analysis showed that compound 4c interacts with Asp273, His317 and Arg166 amino acid residues. Copyright © 2018. Published by Elsevier Ltd.

The convenient preparation of stable aryl-coated zerovalent iron nanoparticles

Directory of Open Access Journals (Sweden)

Olga A. Guselnikova

2015-05-01

Full Text Available A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs were prepared by simple chemical reduction of iron(III chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material.

Experimental prophylaxis and therapy of radiation damage by newly synthesized S-heteryl mercaptoalkyl N-aryl hydrazidimides

Energy Technology Data Exchange (ETDEWEB)

Pantev, T P

1975-01-01

The synthesis is described of representatives of a new class of potential antiradiation agents, the S-heteryl mercaptoalkyl N-aryl hydrazidimices (MHA), obtained by molecular combination of three basic groups of radioprotectors. Toxicity characteristics (LD/sub 100/, LD/sub 50/, and maximum tolerable doses) indicated the compounds tested to be no more toxic for mide and rats than most of the established radioprotective agents. Under acute X-irradiation conditions with minimum absolutely lethal doses, 6 out of the 14 compounds tested showed clear-cut protective properties in mice. These 6 compounds also raised by 20 to 50% the survival of lethally irradiated rats. The most effective preparation was Y-64 (S-2-benzimidazolyl mercaptopropio N-p-tolyl hydrazidimide). This compound is observed to protect hematopoietic tissue in mice (Dose Reduction Factor of 1.29) and rats (Dose Reduction Factor of 1.52) given X-ray doses in the range of 400 to 900 R. With acute gamma irradiation, Y-64, as well as cysteamine, ensured survival of a larger amount of hematopoietic stem cells in bone marrow (using exogenous spleen colony techniques) and a more rapid recovery rate of the stem cell pool. With fractionated X-rays (5 x 100 R daily), Y-64 failed to increase survival, showing, nevertheless, a favorable effect on hematopoietic indices. When administered postradiation, Y-64 failed to influence the course of acute radiation disease in lethally irradiated mice; but, reducing hematopoietic damage, it raised by 40% the survival of lethally irradiated rats. No effect was observed with Y-64 post treatment following either fractionated irradiation (15 x 100 R daily) given to rats or prolonged gamma irradiation (0.28 R/min) to mice. The studies shed light on the mechanism of action of MHA.

Homocoupling of aryl halides in flow: Space integration of lithiation and FeCl3 promoted homocoupling

Directory of Open Access Journals (Sweden)

Aiichiro Nagaki

2011-08-01

Full Text Available The use of FeCl3 resulted in a fast homocoupling of aryllithiums, and this enabled its integration with the halogen–lithium exchange reaction of aryl halides in a flow microreactor. This system allows the homocoupling of two aryl halides bearing electrophilic functional groups, such as CN and NO2, in under a minute.

4-[18F]Fluorophenylpiperazines by Improved Hartwig-Buchwald N-Arylation of 4-[18F]fluoroiodobenzene, Formed via Hypervalent λ3-Iodane Precursors: Application to Build-Up of the Dopamine D4 Ligand [18F]FAUC 316

Directory of Open Access Journals (Sweden)

Fabian Kügler

2014-12-01

Full Text Available Substituted phenylpiperazines are often neuropharmacologically active compounds and in many cases are essential pharmacophores of neuroligands for different receptors such as D2-like dopaminergic, serotoninergic and other receptors. Nucleophilic, no-carrier-added (n.c.a. 18F-labelling of these ligands in an aromatic position is desirable for studying receptors with in vivo molecular imaging. 1-(4-[18F]Fluorophenylpiperazine was synthesized in two reaction steps starting by 18F-labelling of a iodobenzene-iodonium precursor, followed by Pd-catalyzed N-arylation of the intermediate 4-[18F]fluoro-iodobenzene. Different palladium catalysts and solvents were tested with particular attention to the polar solvents dimethylformamide (DMF and dimethylsulfoxide (DMSO. Weak inorganic bases like potassium phosphate or cesium carbonate seem to be essential for the arylation step and lead to conversation rates above 70% in DMF which is comparable to those in typically used toluene. In DMSO even quantitative conversation was observed. Overall radiochemical yields of up to 40% and 60% in DMF and DMSO, respectively, were reached depending on the labelling yield of the first step. The fluorophenylpiperazine obtained was coupled in a third reaction step with 2-formyl-1H-indole-5-carbonitrile to yield the highly selective dopamine D4 ligand [18F]FAUC 316.

Palladium-Catalyzed ortho C-H Arylation of Benzaldehydes Using ortho-Sulfinyl Aniline Transient Auxiliary.

Science.gov (United States)

Mu, Delong; He, Gang; Chen, Gong

2018-05-03

A PdII-catalyzed ortho-(Csp2)-H arylation reaction of benzaldehydes using catalytic amount of 2-methylsulfinyl-aniline as transient auxiliary was developed. This reaction is compatible with a broad range of benzaldehyde and aryl iodide substrates. Compared with other related reaction systems, an excellent regioselectivity for ortho-C(sp2)-H bonds over benzylic C(sp3)-H bonds was obtained for ortho-alkyl-benzaldehyde substrates. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photochemical Aryl Radical Cyclizations to Give (E-3-Ylideneoxindoles

Directory of Open Access Journals (Sweden)

Michael Gurry

2014-09-01

Full Text Available (E-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilylsilane and azo-initiators that gave reduced oxindole adducts.

Discovery of 4-aryl-N-arylcarbonyl-2-aminothiazoles as Hec1/Nek2 inhibitors. Part I: optimization of in vitro potencies and pharmacokinetic properties.

Science.gov (United States)

Lee, Ying-Shuan E; Chuang, Shih-Hsien; Huang, Lynn Y L; Lai, Chun-Liang; Lin, Yu-Hsiang; Yang, Ju-Ying; Liu, Chia-Wei; Yang, Sheng-chuan; Lin, Her-Sheng; Chang, Chia-chi; Lai, Jun-Yu; Jian, Pei-Shiou; Lam, King; Chang, Jia-Ming; Lau, Johnson Y N; Huang, Jiann-Jyh

2014-05-22

A series of 4-aryl-N-arylcarbonyl-2-aminothiazoles of scaffold 4 was designed and synthesized as Hec1/Nek2 inhibitors. Structural optimization of 4 led to compound 32 bearing C-4' 4-methoxyphenoxy and 4-(o-fluoropyridyl)carbonyl groups that showed low nanomolar in vitro antiproliferative activity (IC50: 16.3-42.7 nM), high intravenous AUC (64.9 μM·h, 2.0 mg/kg) in SD rats, and significant in vivo antitumor activity (T/C = 32%, 20 mg/kg, IV) in mice bearing human MDA-MB-231 xenografts. Cell responses resulting from Hec1/Nek2 inhibition were observed in cells treated with 32, including a reduced level of Hec1 coimmunoprecipitated with Nek2, degradation of Nek2, mitotic abnormalities, and apoptosis. Compound 32 showed selectivity toward cancer cells over normal phenotype cells and was inactive in a [(3)H]astemizole competitive binding assay for hERG liability screening. Therefore, 32 is as a good lead toward the discovery of a preclinical candidate targeting Hec1/Nek2 interaction.

Synthesis of aryl-1H-1,2,3-triazoles via 1,3-dipolar cycloaddition

Directory of Open Access Journals (Sweden)

Wagner O. Valença

2012-06-01

Full Text Available A series of Aryl-1H-1,2,3-triazoles were prepared from the reaction between aril-azide (1 with 1.5 equiv. of terminal alkynes (2a-o. The reactions carried out at room temperature and in the presence of CuI (10 mol% in acetonitrile. The compounds (3a-o were obtained in moderate-to-good yields (50-94%. In general, not was observed significant inductive effect on the reactivity of the alkynes (2a-f. The alcohol alkynes (2i-k showed moderate yields 50-72%. On the other hand, the reaction with alkyl alkynes (2m,n furnished the compounds (3m and (3n in excellent yields of 89% and 90%, respectively.

Effects of varying levels of n-6:n-3 fatty acid ratio on plasma fatty acid ...

African Journals Online (AJOL)

Jane

2010-12-20

Dec 20, 2010 ... omega 3 (n-3), omega 6 (n-6) and omega 9 (n-9) fatty acids and are essential in the ... the maintenance of different physiological functions. (Aaes-Jorgensen .... was easier to recognize each one of these cellular types. Mating.

Synthesis and evaluation of ?-hydroxy fatty acid-derived heterocyclic compounds with potential industrial interest

Directory of Open Access Journals (Sweden)

El-Sayed, R.

2006-12-01

Full Text Available T2-Hydroxyheptadecanoic acid chloride (2 reacted with anthranilic acid to produce 2-substituted-3,1-benzoxazin-4-one (3 which was used as starting material to synthesize some condensed and non-condensed heterocyclic compounds by reaction with nitrogen nucleophiles e.g., hydrazine hydrate, and formamide. The products were subjected to reaction with different moles of propylene oxide (n = 5, 10, 15 to produce a novel group of nonionic compounds having a double function as antibacterial and surface active agents which can be used in the manufacturing of drugs, cosmetics, pesticides or can be used as antibacterial and/or antifungal additives. The surface active properties as surface and interfacial tension, cloud point, foaming height, wetting time, and emulsification power were determined, the antimicrobial and biodegradability were also screened.El cloruro del ácido 2-hidroxiheptadecanoico (2 reaccionó con el ácido antranílico para producir 3,1-benzoxazin-4-onas 2-sustituidas que fueron usadas como material de partida en la síntesis de compuestos heterocíclicos condensados y no condensados por reacción con nucleófilos nitrogenados, como la hidracina o la formamida. Los productos fueron hechos reaccionar con diferentes moles de óxido de propileno (n = 5, 10, 15 para producir un grupo nuevo de compuestos no-iónicos teniendo una doble función como antibacterianos y tensoactivos que pueden ser usados en la manufactura de medicamentos, cosméticos, pesticidas, o pueden ser usados como aditivos antibacterianos y/o antifúngicos. Se determinaron diversas propiedades físicas de los compuestos preparados así como sus efectos antimicrobianos y sus biodegrabilidad.

Characterization of two trpE genes encoding anthranilate synthase α-subunit in Azospirillum brasilense

International Nuclear Information System (INIS)

Ge Shimei; Xie Baoen; Chen Sanfeng

2006-01-01

The previous report from our laboratory has recently identified a new trpE gene (termed trpE 2 ) which exists independently in Azospirillum brasilense Yu62. In this study, amplification of trpE(G) (termed trpE 1 (G) here) confirmed that there are two copies of trpE gene, one trpE being fused into trpG while the other trpE existed independently. This is First report to suggest that two copies of the trpE gene exist in this bacterium. Comparison of the nucleotide sequence demonstrated that putative leader peptide, terminator, and anti-terminator were found upstream of trpE 1 (G) while these sequence features did not exist in front of trpE 2 . The β-galactosidase activity of an A. brasilense strain carrying a trpE 2 -lacZ fusion remained constant at different tryptophan concentrations, but the β-galactosidase activity of the same strain carrying a trpE 1 (G)-lacZ fusion decreased as the tryptophan concentration increased. These data suggest that the expression of trpE 1 (G) is regulated at the transcriptional level by attenuation while trpE 2 is constantly expressed. The anthranilate synthase assays with trpE 1 (G) - and trpE 2 - mutants demonstrated that TrpE 1 (G) fusion protein is feedback inhibited by tryptophan while TrpE 2 protein is not. We also found that both trpE 1 (G) and trpE 2 gene products were involved in IAA synthesis

Ruthenium (3) coordination compounds with ethylenediamine-N,N,N',N'-tetramethylphosphonic acid

International Nuclear Information System (INIS)

Ezerskaya, N.A.; Buj Kuang Ki; Shubochkin, L.K.

1987-01-01

In the process of interaction of K 2 Ru(H 2 O)Cl 5 with ethylenediamine-N,N,N',N'-tetramethylphosphonic acid (H 8 EDTP) Ru 3 mono-, bi- and trinuclear complexonates are synthesized. On the basis of IR and X-ray electron spectroscopy and potentiometry suppositions are made on the way of ligand (EDTP, Cl - , H 2 O) coordination. Ru 3 complexonates are characterized using spectrophotometry, polarography, conductometry. Thermal decomposition of the complexonates is studied

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

Directory of Open Access Journals (Sweden)

Rita M. Borik

2007-08-01

Full Text Available The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

Continuous aryl alcohol oxidase production under growth-limited conditions using a trickle bed reactor.

Science.gov (United States)

Pardo-Planas, Oscar; Atiyeh, Hasan K; Prade, Rolf A; Müller, Michael; Wilkins, Mark R

2018-05-01

An A. nidulans strain with a pyridoxine marker was used for continuous production of aryl alcohol oxidase (AAO) in a trickle bed reactor (TBR). Modified medium with reduced zinc, no copper, and 5 g/L ascorbic acid that reduced melanin production and increased AAO productivity under growth limited conditions was used. Two air flow rates, 0.11 L/min (0.1 vvm) and 1.1 L/min (1.0 vvm) were tested. More melanin formation and reduced protein productivity were observed with air flow rate of 1.1 L/min. Three random packings were used as support for the fungus inside the TBR column, two of which were hydrophobic and one which was hydrophilic, and three different dilution rates were tested. The use of GEA BCN 030 hydrophobic packing resulted in greater AAO yield and productivity than the other packings. Increasing dilution rates favored melanin formation and citric, lactic and succinic acid accumulation, which decreased AAO yield and productivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

N-substituted iminodiacetic acids

International Nuclear Information System (INIS)

Nunn, A.; Loberg, M.

1982-01-01

The chemical preparation of several new N-substituted iminodiacetic acid derivatives are described. These compounds when complexed with sup(99m)Tc provide useful radiopharmaceuticals for the external imaging of the hepatobiliary system. (U.K.)

An Efficient and Versatile Synthesis of Isoflavones from 2-Methoxybenzoic Acids

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae In [Duksung Women' s University, Seoul (Korea, Republic of)

2016-07-15

Isoflavones (3-aryl-4H-1-benzopyran-4-ones) are found naturally in soybeans and many plants of the Leguminosae family. They have attracted much attention due to their biological activities, such as their anti-cancer, anti-inflammatory, and antifungal properties. Isoflavones intake through foods is important to human health, because they potentially regulate fatty acid metabolism and methoxy-substituted isoflavones in particular increase cell permeability. Isoflavones have also been synthesized by the coupling of 3-iodochromones with arylboronic acids. The condensation of 2'-hydroxyacetophenones with DMF dimethyl acetal formed 3-(dimethylamino)-2'-hydroxyphenylpropenones, which were cyclized using iodine to form 3-iodochromones. This process was followed by Suzuki coupling with arylboronic acids or aryl boronates to obtain isoflavones. The synthesis of isoflavones (6) from 5 was based on the formylation of the methylene group of 5 using DMF-POCl{sub 3}. Previously, the reaction of the DMF-POCl{sub 3} complex on benzyl 2-hydroxyphenyl ketones led to isoflavones, for which DMF was used as the reagent and solvent for 18 h at gentle reflux.

Browse Title Index

African Journals Online (AJOL)

... effects of four derivatives of salicylic acid and anthranilic acid in mice and rats, Abstract PDF ... Vol 10, No 44 (2011), Antisense-induced suppression of taxoid 14β- hydroxylase gene expression in transgenic ... OC Enechi, OFC Nwodo.

Conformationally locked aryl C-nucleosides: synthesis of phosphoramidite monomers and incorporation into single-stranded DNA and LNA (locked nucleic acid)

DEFF Research Database (Denmark)

Babu, B. Ravindra; Prasad, Ashok K.; Trikha, Smriti

2002-01-01

. The phosphoramidite approach was used for automated incorporation of the LNA-type beta-configured C-aryl monomers 17a-17e into short DNA and 2'-OMe-RNA/LNA strands. It is shown that universal hybridization can be obtained with a conformationally restricted monomer as demonstrated most convincingly for the pyrene LNA...... monomer 17d, both in a DNA context and in an RNA-like context. Increased binding affinity of oligonucleotide probes for universal hybridization can be induced by combining the pyrene LNA monomer 17d with affinity-enhancing 2'-OMe-RNA/LNA monomers....

In vitro cytotoxicity and apoptotic inducing activity of the synthesized 4-aryl-4H-chromenes derivatives against human cancer cell lines

Directory of Open Access Journals (Sweden)

Mohagheghi MA

2009-09-01

Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: 4-Aryl-4H-chromenes are novel anticancer agents which induce apoptosis in cancer cells. These compounds were found to induce apoptosis by targeting the tubulin/microtubule system in cell proliferation process. The aim of this study was to report cyototoxic and apoptosis inducing activities of a new series of synthesized 4-aryl-4H-chromenes compounds."n"n Methods: The in vitro cytotoxic activity of the synthesized 4-aryl-4H-chromenes was investigated against a paned of human cancer cell lines including MCF-7 (breast carcinoma, A549 (lung carcinoma, HEPG-2 (liver carcinoma, SW-480 (colon adenocarcinoma, U87-MG (glioblastoma, 1321N1 (astrocytoma, and DAOY (medulloblastoma. The percentage of growth inhibitory activity was evaluated using MTT colorimetric assay versus controls not treated with test derivatives. The data for etoposide, a well known anticancer drug, was included for comparison. For each compound, the 50% inhibitory concentration (IC50 were determined. Apoptosis inducing activity were assessed by DAPI staining."n"n Results: Preliminary screening showed that those chromenes analogs bearing phenyl-isoxazole-3-yl substitution or the derivatives containing methoxyphenyl in chromene ring exhibited

Synthesis of enyne and aryl vinyl sulfoxides: functionalization via Pummerer rearrangement.

Science.gov (United States)

Souza, Frederico B; Shamim, Anwar; Argomedo, Luiz M Z; Pimenta, Daniel C; Stefani, Hélio A

2015-11-01

An efficient methodology for the synthesis of aryl-substituted vinyl sulfoxides through direct substitution of aryl-substituted alkynyl grignard reagents on menthyl-p-toluenesulfinate followed by Suzuki-Miyaura cross-coupling reaction has been developed. It has also been described that the reaction of alkyl-substituted and cycloalkyl-substituted alkynyl grignard reagents with menthyl-p-toluenesulfinate led to two products, i.e., alkynyl sulfoxide derivatives, as a result of substitution, and enyne sulfoxide derivatives, which resulted from substitution followed by Michael type addition. It was possible to selectively synthesize the enyne sulfoxide derivatives by changing the concentration of the grignard reagent. These alkenyl sulfoxides were transformed into the corresponding [Formula: see text]-thio aldehydes in high yields via additive Pummerer rearrangement.

Lewis acid catalyzed [3 + 2] annulation of ketenimines with donor-acceptor cyclopropanes: an approach to 2-alkylidenepyrrolidine derivatives.

Science.gov (United States)

Alajarin, Mateo; Egea, Adrian; Orenes, Raul-Angel; Vidal, Angel

2016-11-02

The [3 + 2] annulation reaction of C,C,N-trisubstituted ketenimines with donor-acceptor cyclopropanes bearing aryl, styryl and vinyl substituents at the C2 position, triggered by the Lewis acid Sc(OTf) 3 , supplies highly substituted pyrrolidines. Activated cyclopropanes fused to naphthalene and [1]benzopyrane nuclei are also suitable substrates in similar transformations, yielding partially saturated benz[g]indoles and [1]benzopyran[4,3-b]pyrroles. An intramolecular version of this ketenimine/cyclopropane [3 + 2] annulation has also been developed leading to the pyrrolo[2,1-a]isoindole framework.

Microwave Assisted Synthesis of N-Arylheterocyclic Substituted-4-aminoquinazoline Derivatives

Directory of Open Access Journals (Sweden)

Ping Lu

2006-04-01

Full Text Available A simple, efficient, and general method has been developed for the synthesis of various N-aryl heterocylic substituted-4-aminoquinazoline compounds from 4-chloro- quinazoline and aryl heterocyclic amines under microwave irradiation using 2-propanol as solvent. The advantages of the use of microwave irradiation in relation to the classical method were demonstrated.

An endogenous aryl hydrocarbon receptor ligand inhibits proliferation and migration of human ovarian cancer cells.

Science.gov (United States)

Wang, Kai; Li, Yan; Jiang, Yi-Zhou; Dai, Cai-Feng; Patankar, Manish S; Song, Jia-Sheng; Zheng, Jing

2013-10-28

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor mediates many biological processes. Herein, we investigated if 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE, an endogenous AhR ligand) regulated proliferation and migration of human ovarian cancer cells via AhR. We found that AhR was widely present in many histotypes of ovarian cancer tissues. ITE suppressed OVCAR-3 cell proliferation and SKOV-3 cell migration in vitro, which were blocked by AhR knockdown. ITE also suppressed OVCAR-3 cell growth in mice. These data suggest that the ITE might potentially be used for therapeutic intervention for at least a subset of human ovarian cancer. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Aryl substitution of pentacenes

Directory of Open Access Journals (Sweden)

Andreas R. Waterloo

2014-07-01

Full Text Available A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films, thermoanalytical methods (DSC and TGA, cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives. X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices.

Aryl substitution of pentacenes

Science.gov (United States)

Waterloo, Andreas R; Sale, Anna-Chiara; Lehnherr, Dan; Hampel, Frank

2014-01-01

Summary A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films), thermoanalytical methods (DSC and TGA), cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives). X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices. PMID:25161729

Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

Energy Technology Data Exchange (ETDEWEB)

Pastre, Julio C.; Correia, Carlos R.D., E-mail: genisson@chimie.ups-tlse.f, E-mail: roque@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica; Genisson, Yves [Universite Paul Sabatier, Toulouse (France). Lab. de Synthese et Physicochimie des Molecules d' Interet Biologique; Saffon, Nathalie [Universite Paul Sabatier, Toulouse (France). Structure federative toulousaine en chimie moleculaire (SFTCM); Dandurand, Jany [Universite Paul Sabatier, Toulouse (France). Lab. de Physique des Polymeres

2010-07-01

New achiral and chiral RTILs were prepared using novel and/or optimized synthetic routes. These new series of imidazolinium, imidazolium, pyridinium and nicotine-derived ionic liquids were fully characterized including differential scanning calorimetry (DSC) analysis. The performance of these achiral and chiral room temperature ionic liquids (RTILs) was demonstrated by means of the Heck arylation of endocyclic acrylates employing arenediazonium salts and aryl iodides. The Heck arylations performed in the presence of these ionic entities, either as a solvent or as an additive, were effective leading to complete conversion of the substrate and good to excellent yield of the Heck adduct. In spite of the good performances, no asymmetric induction was observed in any of the cases studied. Two new diastereoisomeric NHC-palladium complexes were prepared in good yields from a chiral imidazolium salt and their structure characterized by X-ray diffraction. Overall, the Heck arylations employing arenediazonium tetrafluoroborates in RTILs were more effective than the traditional protocols employing aryl iodides in terms of reactivity and yields. (author)

A one-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents.

Science.gov (United States)

Sloan, Nikki L; Luthra, Sajinder K; McRobbie, Graeme; Pimlott, Sally L; Sutherland, Andrew

2017-10-05

An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125 I-labelled aryl compounds and SPECT radiotracers.

Assembly of phosphonic acids on GaN and AlGaN

Energy Technology Data Exchange (ETDEWEB)

Simpkins, B S; Stine, R; Theodore, N D; Pehrsson, P E [Chemistry Division, Naval Research Laboratory, Washington DC (United States); Hong, S [Thomas Jefferson High School, McClean, VA (United States); Maekinen, A J [Optical Sciences Division, Naval Research Laboratory, Washington, DC (United States); Mastro, M A; Eddy, C R Jr [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC (United States)

2010-01-13

Self-assembled monolayers of octadecylphosphonic acid and 16-phosphonohexadecanoic acid (PHDA) were formed on the semiconductor substrates gallium nitride (GaN) and aluminium gallium nitride (AlGaN). The presence of the molecular layers was verified through x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Structural information was acquired with infrared spectroscopy which verified the bonding orientation of the carboxyl-containing PHDA. The impact of the molecular layers on the channel conductivity and the surface electronic structure of an AlGaN/GaN heterostructure was measured. Our results indicate that pinning of the surface Fermi level prohibits modification of the channel conductivity by the layer. However, a surface dipole of {approx}0.8 eV is present and associated with both phosphonic acid layers. These results are of direct relevance to field-effect-based biochemical sensors and metal-semiconductor contact formation for this system and provide a fundamental basis for further applications of GaN and AlGaN technology in the fields of biosensing and microelectronics.

U(SMes*)n, (n=3, 4) and Ln(SMes*)3 (Ln = La, Ce, Pr, Nd): Lanthanide(III)/actinide(III) differentiation in agostic interactions and an unprecedented eta(3) Ligation mode of the aryl-thiolate ligand, from X-ray diffraction and DFT analysis

International Nuclear Information System (INIS)

Roger, Mathieu; Barros, Noemi; Arliguie, Therese; Thuery, Pierre; Maron, Laurent; Ephritikhine, Michel

2006-01-01

Reaction of U(NEt 2 ) 4 with HS-2,4,6- t Bu 3 C 6 H 2 (HSMes*) gave U(SMes*) 3 (NEt 2 )(py) (1), whereas similar treatment of U[N(SiMe 3 )SiMe 2 CH 2 ][N(SiMe 3 ) 2 ] 2 afforded U(SMes*)[N(SiMe 3 ) 2 ] 3 (2) and U(SMes*) 3 [N(SiMe 3 ) 2 ]. The first neutral homoleptic uranium(IV) thiolate to have been crystallographically characterized, U(SMes*) 4 (4), was isolated from the reaction of U(BH 4 ) 4 and KSMes*. The first homoleptic thiolate complex of uranium(III), U(SMes*) 3 (5), was synthesized by proton-lysis of U[N(SiMe 3 ) 2 ] 3 with HSMes* in cyclohexane. The crystal structure of 5 exhibits the novel η 3 ligation mode for the aryl-thiolate ligand. Comparison of the crystal structure of 5 with those of the isomorphous lanthanide congeners Ln(SMes*) 3 (Ln) La, Ce, Pr, and Nd) indicates that the U-S, U-C ipso , and U-C ortho bond lengths are shorter than the corresponding ones in the 4f-element analogues, when taking into account the variation in the ionic radii of the metals. The distance between the uranium and the carbon atoms involved in the U center dot center dot center dot H-C ε agostic interaction of each thiolate ligand is shorter, by ∼ 0.05 angstrom, than that expected from a purely ionic bonding model. The lanthanide( III)/actinide(III) differentiation was analyzed by density functional theory (DFT). The nature of the M-S bond is shown to be ionic strongly polarized at the sulfur for M) U and ion-covalent (i.e. strongly ionic with low orbital interaction), for M) Ln. The strength of the U center dot center dot center dot H-C ε agostic interaction is proposed to be controlled by the maximization of the interaction between U + and S - under steric constraints. The η 3 ligation mode of the aryl-thiolate ligand is also obtained from DFT. (authors)

The Use of 4-(3,4-Dichlorophenyl-4-Oxo-2-(4-Antipyrinyl-Butanoic Acid in the Preparation of Some New Heterocyclic Compounds With Expected Biological Activity

Directory of Open Access Journals (Sweden)

M. Shafik

2003-03-01

Full Text Available Reaction of 4-oxo-4-(3,4-dichlorophenyl-2-butenoic acid (1 with antipyrin (2 gave the corresponding butanoic acid 3. Reaction of 3 with hydrazines gave the pyridazinone derivatives 5a,b. Compounds 5a,b were used to prepare the corresponding dithio derivatives. Reaction of 5a with POCl3 unexpectedly gave the chloropyridazine derivative 7, which is used to prepare the corresponding thio derivative. The hitherto unknown reactions of this chloro derivative with 2-amino-3-carbethoxy-4,5-dimethylthiophene and 2-amino-3-carbethoxy tetrahydrobenzothiophene have now been described. The behaviour of the chloro derivative toward hydrazine hydrate, sodium azide and anthranilic acid was also studied. Some of the new compounds showed antimicrobial and antifungal activities .

Ruthenium (3) coordination compounds with ethylenediamine-N,N,N',N'-tetramethylphosphonic acid

Energy Technology Data Exchange (ETDEWEB)

Ezerskaya, N A; Ki, Buj Kuang; Shubochkin, L K

1987-12-01

In the process of interaction of K/sub 2/Ru(H/sub 2/O)Cl/sub 5/ with ethylenediamine-N,N,N',N'-tetramethylphosphonic acid (H/sub 8/EDTP) Ru/sup 3/ mono-, bi- and trinuclear complexonates are synthesized. On the basis of IR and X-ray electron spectroscopy and potentiometry suppositions are made on the way of ligand (EDTP, Cl/sup -/, H/sub 2/O) coordination. Ru/sup 3/ complexonates are characterized using spectrophotometry, polarography, conductometry. Thermal decomposition of the complexonates is studied.

N-3 fatty acids reduced trans fatty acids retention and increased docosahexaenoic acid levels in the brain.

Science.gov (United States)

Lavandera, Jimena Verónica; Saín, Juliana; Fariña, Ana Clara; Bernal, Claudio Adrián; González, Marcela Aída

2017-09-01

The levels of docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) are critical for the normal structure and function of the brain. Trans fatty acids (TFA) and the source of the dietary fatty acids (FA) interfere with long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis. The aim of this study was to investigate the effect of TFA supplementation in diets containing different proportions of n-9, n-6, and n-3 FA on the brain FA profile, including the retention of TFA, LC-PUFA levels, and n-6/n-3 PUFA ratios. These parameters were also investigated in the liver, considering that LC-PUFA are mainly bioconverted from their dietary precursors in this tissue and transported by serum to the brain. Also, stearoyl-CoA desaturase-1 (SCD1) and sterol regulatory element-binding protein-1c (SREBP-1c) gene expressions were evaluated. Male CF1 mice were fed (16 weeks) diets containing different oils (olive, corn, and rapeseed) with distinct proportions of n-9, n-6, and n-3 FA (55.2/17.2/0.7, 32.0/51.3/0.9, and 61.1/18.4/8.6), respectively, substituted or not with 0.75% of TFA. FA composition of the brain, liver, and serum was assessed by gas chromatography. TFA were incorporated into, and therefore retained in the brain, liver, and serum. However, the magnitude of retention was dependent on the tissue and type of isomer. In the brain, total TFA retention was lower than 1% in all diets. Dietary n-3 PUFA decreased TFA retention and increased DHA accretion in the brain. The results underscore the importance of the type of dietary FA on the retention of TFA in the brain and also on the changes of the FA profile.

Aryl Polyenes, a Highly Abundant Class of Bacterial Natural Products, Are Functionally Related to Antioxidative Carotenoids.

Science.gov (United States)

Schöner, Tim A; Gassel, Sören; Osawa, Ayako; Tobias, Nicholas J; Okuno, Yukari; Sakakibara, Yui; Shindo, Kazutoshi; Sandmann, Gerhard; Bode, Helge B

2016-02-02

Bacterial pigments of the aryl polyene type are structurally similar to the well-known carotenoids with respect to their polyene systems. Their biosynthetic gene cluster is widespread in taxonomically distant bacteria, and four classes of such pigments have been found. Here we report the structure elucidation of the aryl polyene/dialkylresorcinol hybrid pigments of Variovorax paradoxus B4 by HPLC-UV-MS, MALDI-MS and NMR. Furthermore, we show for the first time that this pigment class protects the bacterium from reactive oxygen species, similarly to what is known for carotenoids. An analysis of the distribution of biosynthetic genes for aryl polyenes and carotenoids in bacterial genomes is presented; it shows a complementary distribution of these protective pigments in bacteria. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Activation of aryl hydrocarbon receptor reduces carbendazim-induced cell death

International Nuclear Information System (INIS)

Wei, Kuo-Liang; Chen, Fei-Yun; Lin, Chih-Yi; Gao, Guan-Lun; Kao, Wen-Ya; Yeh, Chi-Hui; Chen, Chang-Rong; Huang, Hao-Chun; Tsai, Wei-Ren; Jong, Koa-Jen; Li, Wan-Jung; Su, Jyan-Gwo Joseph

2016-01-01

Carbendazim inhibits microtubule assembly, thus blocking mitosis and inhibiting cancer cell proliferation. Accordingly, carbendazim is being explored as an anticancer drug. Data show that carbendazim increased mRNA and protein expressions and promoter activity of CYP1A1. In addition, carbendazim activated transcriptional activity of the aryl hydrocarbon response element, and induced nuclear translocation of the aryl hydrocarbon receptor (AhR), a sign the AhR is activated. Carbendazim-induced CYP1A1 expression was blocked by AhR antagonists, and was abolished in AhR signal-deficient cells. Results demonstrated that carbendazim activated the AhR, thereby stimulating CYP1A1 expression. In order to understand whether AhR-induced metabolic enzymes turn carbendazim into less-toxic metabolites, Hoechst 33342 staining to reveal carbendazim-induced nuclear changes and flow cytometry to reveal the subG 0 /G 1 population were applied to monitor carbendazim-induced cell apoptosis. Carbendazim induced less apoptosis in Hepa-1c1c7 cells than in AhR signal-deficient Hepa-1c1c7 mutant cells. Pretreatment with β-NF, an AhR agonist that highly induces CYP1A1 expression, decreased carbendazim-induced cell death. In addition, the lower the level of AhR was, the lower the vitality present in carbendazim-treated cells, including hepatoma cells and their derivatives with AhR RNA interference, also embryonic kidney cells, bladder carcinoma cells, and AhR signal-deficient Hepa-1c1c7 cells. In summary, carbendazim is an AhR agonist. The toxicity of carbendazim was lower in cells with the AhR signal. This report provides clues indicating that carbendazim is more potent at inducing cell death in tissues without than in those with the AhR signal, an important reference for applying carbendazim in cancer chemotherapy. - Highlights: • Carbendazim induced transcriptional activity of the aryl hydrocarbon response element. • Carbendazim induced nuclear translocation of the aryl hydrocarbon

Activation of aryl hydrocarbon receptor reduces carbendazim-induced cell death

Energy Technology Data Exchange (ETDEWEB)

Wei, Kuo-Liang [Division of Gastroenterology and Hepatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan, ROC (China); College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan, ROC (China); Chen, Fei-Yun; Lin, Chih-Yi [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China); Gao, Guan-Lun [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China); Department of Biological Resources, National Chiayi University, Chiayi, 60004, Taiwan, ROC (China); Kao, Wen-Ya [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China); Yeh, Chi-Hui [Department of Environmental Engineering, College of Engineering, Da-Yeh University, Dacun, Changhua 51591, Taiwan, ROC (China); Chen, Chang-Rong [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China); Huang, Hao-Chun [Division of Gastroenterology and Hepatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan, ROC (China); Tsai, Wei-Ren [Division of Applied Toxicology, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Executive Yuan, Taichung 41358, Taiwan, ROC (China); Jong, Koa-Jen [Department of Biological Resources, National Chiayi University, Chiayi, 60004, Taiwan, ROC (China); Li, Wan-Jung [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China); Su, Jyan-Gwo Joseph, E-mail: jgjsu@mail.ncyu.edu.tw [Department of Biochemical Science and Technology, National Chiayi University, Chiayi 60004, Taiwan, ROC (China)

2016-09-01

Carbendazim inhibits microtubule assembly, thus blocking mitosis and inhibiting cancer cell proliferation. Accordingly, carbendazim is being explored as an anticancer drug. Data show that carbendazim increased mRNA and protein expressions and promoter activity of CYP1A1. In addition, carbendazim activated transcriptional activity of the aryl hydrocarbon response element, and induced nuclear translocation of the aryl hydrocarbon receptor (AhR), a sign the AhR is activated. Carbendazim-induced CYP1A1 expression was blocked by AhR antagonists, and was abolished in AhR signal-deficient cells. Results demonstrated that carbendazim activated the AhR, thereby stimulating CYP1A1 expression. In order to understand whether AhR-induced metabolic enzymes turn carbendazim into less-toxic metabolites, Hoechst 33342 staining to reveal carbendazim-induced nuclear changes and flow cytometry to reveal the subG{sub 0}/G{sub 1} population were applied to monitor carbendazim-induced cell apoptosis. Carbendazim induced less apoptosis in Hepa-1c1c7 cells than in AhR signal-deficient Hepa-1c1c7 mutant cells. Pretreatment with β-NF, an AhR agonist that highly induces CYP1A1 expression, decreased carbendazim-induced cell death. In addition, the lower the level of AhR was, the lower the vitality present in carbendazim-treated cells, including hepatoma cells and their derivatives with AhR RNA interference, also embryonic kidney cells, bladder carcinoma cells, and AhR signal-deficient Hepa-1c1c7 cells. In summary, carbendazim is an AhR agonist. The toxicity of carbendazim was lower in cells with the AhR signal. This report provides clues indicating that carbendazim is more potent at inducing cell death in tissues without than in those with the AhR signal, an important reference for applying carbendazim in cancer chemotherapy. - Highlights: • Carbendazim induced transcriptional activity of the aryl hydrocarbon response element. • Carbendazim induced nuclear translocation of the aryl

Metal and base free synthesis of primary amines via ipso amination of organoboronic acids mediated by [bis(trifluoroacetoxy)iodo]benzene (PIFA).

Science.gov (United States)

Chatterjee, Nachiketa; Goswami, Avijit

2015-08-07

A metal and base free synthesis of primary amines has been developed at ambient temperature through ipso amination of diversely functionalized organoboronic acids, employing a combination of [bis(trifluoroacetoxy)iodo]benzene (PIFA)-N-bromosuccinimide (NBS) and methoxyamine hydrochloride as the aminating reagent. The amines were primarily obtained as their trifluoroacetate salts which on subsequent aqueous alkaline work up provided the corresponding free amines. The combination of PIFA-NBS is found to be the mildest choice compared to the commonly used strong bases (e.g. n-BuLi, Cs2CO3) for activating the aminating agent. The reaction is expected to proceed via activation of the aminating reagent followed by B-N 1,2-aryl migration.

Alkyl and aryl phosphorodiiodidites. Pt. 2

International Nuclear Information System (INIS)

Feshchenko, N.G.; Kostina, V.G.

1976-01-01

Alkyl phosphorodiiodidites are formed in the reactions of alkyl phosphorodichloridites with lithium iodide. They are stable at -60 to -50 0 . When warmed to 20 0 , they disproportionate with conversion into trialkyl phosphites and phosphorus triiodide. The latter also react together and give alkyl iodides, diphosphorus tetraiodide, and a polymer of unestablished structure. Diaryl and dialkyl phosphoriodidites are stable only in solution at low temperatures. They disproportionate in a similar way to aryl and alkyl phosphorodiiodidites. Alkyl phosphorodiiodidites react with iodine with the formation of alkyl iodides and phosphoryl iodide

Silica-Supported Catalyst for Enantioselective Arylation of Aldehydes under Batch and Continuous-Flow Conditions.

Science.gov (United States)

Watanabe, Satoshi; Nakaya, Naoyuki; Akai, Junichiro; Kanaori, Kenji; Harada, Toshiro

2018-05-04

A silica-supported 3-aryl H 8 -BINOL-derived titanium catalyst exhibited high performance in the enantioselective arylation of aromatic aldehydes using Grignard and organolithium reagents not only under batch conditions but also under continuous-flow conditions. Even with a simple pipet reactor packed with the heterogeneous catalyst, the enantioselective production of chiral diarylmethanols could be achieved through a continuous introduction of aldehydes and mixed titanium reagents generated from the organometallic precursors. The pipet reactor could be used repeatedly in different reactions without appreciable deterioration of the activity.

Synthesis and Biological Activity of 3-(2-Furanyl-6-Aryl-1,2,4-Triazolo[3,4-b]-1,3,4 –Thiadiazoles

Directory of Open Access Journals (Sweden)

Zi-Yi Zhang

2002-08-01

Full Text Available 3-(2-Furanyl-4-amino-5-mercapto-1,2,4-triazole (1 was prepared from 2-furoic acid through a multi-step reaction sequence. Compound 1 reacted with aromatic acids in the presence of phosphorus oxychloride to give 3-(2-furanyl-6-aryl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles (2. The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectra. The bioassay indicated most of the title compounds possess significant growth promoting effects on mung bean radicles.

Enantioselective synthesis of chiral 3-aryl-1-indanones through rhodium-catalyzed asymmetric intramolecular 1,4-addition.

Science.gov (United States)

Yu, Yue-Na; Xu, Ming-Hua

2013-03-15

Enantioselective synthesis of potentially useful chiral 3-aryl-1-indanones was achieved through a rhodium-catalyzed asymmetric intramolecular 1,4-addition of pinacolborane chalcone derivatives using extraordinary simple MonoPhos as chiral ligand under relatively mild conditions. This novel protocol offers an easy access to a wide variety of enantioenriched 3-aryl-1-indanone derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 95% ee).

Design and synthesis of N₁-aryl-benzimidazoles 2-substituted as novel HIV-1 non-nucleoside reverse transcriptase inhibitors.

Science.gov (United States)

Monforte, Anna-Maria; Ferro, Stefania; De Luca, Laura; Lo Surdo, Giuseppa; Morreale, Francesca; Pannecouque, Christophe; Balzarini, Jan; Chimirri, Alba

2014-02-15

A series of novel N1-aryl-2-arylthioacetamido-benzimidazoles were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Some of them proved to be effective in inhibiting HIV-1 replication at submicromolar and nanomolar concentration acting as HIV-1 non-nucleoside RT inhibitors (NNRTIs), with low cytotoxicity. The preliminary structure-activity relationship (SAR) of these new derivatives was discussed and rationalized by docking studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pork as a Source of Omega-3 (n-3) Fatty Acids.

Science.gov (United States)

Dugan, Michael E R; Vahmani, Payam; Turner, Tyler D; Mapiye, Cletos; Juárez, Manuel; Prieto, Nuria; Beaulieu, Angela D; Zijlstra, Ruurd T; Patience, John F; Aalhus, Jennifer L

2015-12-16

Pork is the most widely eaten meat in the world, but typical feeding practices give it a high omega-6 (n-6) to omega-3 (n-3) fatty acid ratio and make it a poor source of n-3 fatty acids. Feeding pigs n-3 fatty acids can increase their contents in pork, and in countries where label claims are permitted, claims can be met with limited feeding of n-3 fatty acid enrich feedstuffs, provided contributions of both fat and muscle are included in pork servings. Pork enriched with n-3 fatty acids is, however, not widely available. Producing and marketing n-3 fatty acid enriched pork requires regulatory approval, development costs, quality control costs, may increase production costs, and enriched pork has to be tracked to retail and sold for a premium. Mandatory labelling of the n-6/n-3 ratio and the n-3 fatty acid content of pork may help drive production of n-3 fatty acid enriched pork, and open the door to population-based disease prevention polices (i.e., food tax to provide incentives to improve production practices). A shift from the status-quo, however, will require stronger signals along the value chain indicating production of n-3 fatty acid enriched pork is an industry priority.

Pork as a Source of Omega-3 (n-3) Fatty Acids

Science.gov (United States)

Dugan, Michael E.R.; Vahmani, Payam; Turner, Tyler D.; Mapiye, Cletos; Juárez, Manuel; Prieto, Nuria; Beaulieu, Angela D.; Zijlstra, Ruurd T.; Patience, John F.; Aalhus, Jennifer L.

2015-01-01

Pork is the most widely eaten meat in the world, but typical feeding practices give it a high omega-6 (n-6) to omega-3 (n-3) fatty acid ratio and make it a poor source of n-3 fatty acids. Feeding pigs n-3 fatty acids can increase their contents in pork, and in countries where label claims are permitted, claims can be met with limited feeding of n-3 fatty acid enrich feedstuffs, provided contributions of both fat and muscle are included in pork servings. Pork enriched with n-3 fatty acids is, however, not widely available. Producing and marketing n-3 fatty acid enriched pork requires regulatory approval, development costs, quality control costs, may increase production costs, and enriched pork has to be tracked to retail and sold for a premium. Mandatory labelling of the n-6/n-3 ratio and the n-3 fatty acid content of pork may help drive production of n-3 fatty acid enriched pork, and open the door to population-based disease prevention polices (i.e., food tax to provide incentives to improve production practices). A shift from the status-quo, however, will require stronger signals along the value chain indicating production of n-3 fatty acid enriched pork is an industry priority. PMID:26694475

Pork as a Source of Omega-3 (n-3 Fatty Acids

Directory of Open Access Journals (Sweden)

Michael E.R. Dugan

2015-12-01

Full Text Available Pork is the most widely eaten meat in the world, but typical feeding practices give it a high omega-6 (n-6 to omega-3 (n-3 fatty acid ratio and make it a poor source of n-3 fatty acids. Feeding pigs n-3 fatty acids can increase their contents in pork, and in countries where label claims are permitted, claims can be met with limited feeding of n-3 fatty acid enrich feedstuffs, provided contributions of both fat and muscle are included in pork servings. Pork enriched with n-3 fatty acids is, however, not widely available. Producing and marketing n-3 fatty acid enriched pork requires regulatory approval, development costs, quality control costs, may increase production costs, and enriched pork has to be tracked to retail and sold for a premium. Mandatory labelling of the n-6/n-3 ratio and the n-3 fatty acid content of pork may help drive production of n-3 fatty acid enriched pork, and open the door to population-based disease prevention polices (i.e., food tax to provide incentives to improve production practices. A shift from the status-quo, however, will require stronger signals along the value chain indicating production of n-3 fatty acid enriched pork is an industry priority.

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as potent urease inhibitors.

Science.gov (United States)

Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

2015-02-01

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58 μM. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637). © 2014 John Wiley & Sons A/S.

Carbon Dioxide-Mediated C(sp3)-H Arylation of Amine Substrates.

Science.gov (United States)

Kapoor, Mohit; Liu, Daniel; Young, Michael C

2018-05-25

Elaborating amines via C-H functionalization has been an important area of research over the past decade but has generally relied on an added directing group or sterically hindered amine approach. Since free-amine-directed C(sp 3 )-H activation is still primarily limited to cyclization reactions and to improve the sustainability and reaction scope of amine-based C-H activation, we present a strategy using CO 2 in the form of dry ice that facilitates intermolecular C-H arylation. This methodology has been used to enable an operationally simple procedure whereby 1° and 2° aliphatic amines can be arylated selectively at their γ-C-H positions. In addition to potentially serving as a directing group, CO 2 has also been demonstrated to curtail the oxidation of sensitive amine substrates.

Copper-Assisted Oxidative Trifluoromethylthiolation of 2,3-Allenoic Acids with AgSCF3.

Science.gov (United States)

Pan, Shen; Huang, Yangen; Xu, Xiu-Hua; Qing, Feng-Ling

2017-09-01

The oxidative trifluoromethylthiolation of 2,3-allenoic acids with AgSCF 3 in the presence of (NH 4 ) 2 S 2 O 8 and catalytic copper salt was investigated. A series of 4-aryl-2,3-allenoic acids underwent radical trifluoromethylthiolation/intramolecular cyclization to afford β-trifluoromethylthiolated butenolides, which were conveniently transformed into trifluoromethylthiolated furan derivatives. In contrast, 2-monosubstituted 2,3-allenoic acids were converted into the corresponding 3,4-bis(trifluoromethylthio)but-2-enoic-acids under similar reaction conditions.

Synthesis of aryl-substituted 5-[18F]fluoroalkylbenzamides: High affinity ligands for dopamine D-2 studies

International Nuclear Information System (INIS)

Mathis, C.A.; Bishop, J.E.; Gerdes, J.M.; Faggin, B.; Mailman, R.

1990-01-01

Recent studies of the structure-activity relationship of benzamides have shown that the 2,3-dimethoxy substitution pattern of (S)-N-[(1-ethyl-2-pyrrolidinyl)methyl]-2,3-dimethoxy-5-iodobenzamide (PDB) resulted in a potent D-2 antagonist. Based upon these results and the concept that the potency of receptor ligands can be preserved when aromatic halogen substituents are replaced by fluoroalkyl functional groups, the authors synthesized a series of aryl-substituted fluoroalkyl PDBs and salicylamides. Synthetic pathways and an in vivo study in rats are outlined

Study on mechanism for oxidation of N,N-dimethylhydroxylamine by nitrous acid

International Nuclear Information System (INIS)

Li Gaoliang; He Hui

2011-01-01

The oxidation of N,N-dimethylhydroxylamine (DMHAN) by nitrous acid is investigated in perchloric acid and nitric acid medium, respectively. The effects of H + , DMHAN, ionic strength and temperature on the reaction are studied. The rate equation in perchloric acid medium has been determined to be -d[HNO 2 ]/dt = k[DMHAN][HNO 2 ], where k = 12.8 ± 1.0 (mol/L) -1 min -1 when the temperature is 18.5 deg C and the ionic strength is 0.73 mol/L with an activation energy about 41.5 kJ mol -1 . The reaction becomes complicated when it is performed in nitric acid medium. When the molarity of HNO 3 is higher than 1.0 mol/L, nitrous acid will be produced via the reaction between nitric acid and DMHAN. The reaction products are analyzed and the reaction mechanism is discussed in this paper. (author)

Cyprodinil as an activator of aryl hydrocarbon receptor

International Nuclear Information System (INIS)

Fang, Chien-Chung; Chen, Fei-Yun; Chen, Chang-Rong; Liu, Chien-Chiang; Wong, Liang-Chi; Liu, Yi-Wen; Su, Jyan-Gwo Joseph

2013-01-01

Highlights: ► Cyprodinil activated the aryl hydrocarbon receptor (AHR). ► Cyprodinil induced nuclear translocation of the AHR, and the expression of CYP1A1. ► Cyprodinil enhanced dexamethasone-induced gene expression. ► Cyprodinil phosphorylated ERK, indicating its deregulation of ERK activity. -- Abstract: Cyprodinil is a pyrimidinamine fungicide, used worldwide by agriculture. It is used to protect fruit plants and vegetables from a wide range of pathogens. Benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor (AHR) ligands. Although the structure of cyprodinil distinctly differs from those of BaP and TCDD, our results show that cyprodinil induced nuclear translocation of the AHR, and induced the transcriptional activity of aryl hydrocarbon response element (AHRE). Cyprodinil induced the expression of cytochrome P450 (CYP) 1A1, a well-known AHR-targeted gene, in ovarian granulosa cells, HO23, and hepatoma cells, Hepa-1c1c7. Its induction did not appear in AHR signal-deficient cells, and was blocked by the AHR antagonist, CH-223191. Cyprodinil decreased AHR expression in HO23 cells, resulting in CYP1A1 expression decreasing after it peaked at 9 h of treatment in HO23 cells. Dexamethasone is a synthetic agonist of glucocorticoids. Cyprodinil enhanced dexamethasone-induced gene expression, and conversely, its induction of CYP1A1 expression was decreased by dexamethasone in HO23 cells, indicating its induction of crosstalk between the AHR and glucocorticoid receptor and its role as a potential endocrine disrupter. In addition to BaP, TCDD, and an AHR agonist, β-NF, cyprodinil also phosphorylated extracellular signal-regulated kinase (ERK) in HO23 and Hepa-1c1c7 cells, indicating its deregulation of ERK activity. In summary, our results demonstrate that cyprodinil, similar to BaP, acts as an AHR activator, a potential endocrine disrupter, and an ERK disrupter

OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles

Directory of Open Access Journals (Sweden)

Baskar Nammalwar

2015-12-01

Full Text Available OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

Dimethylurea/citric acid as a highly efficient deep eutectic solvent

Indian Academy of Sciences (India)

Dimethylurea/citric acid deep eutectic solvent was used as a dual catalyst and a green reaction medium for the efficient synthesis of bis(indolyl)methanes, quinolines and aryl-4, 5-diphenyl-1H-imidazoles. Ease of recovery and reusability of DES with high activity makes this method efficient and eco-friendly.

A Facial Protocol for the Synthesis of Benzofuran Derivatives by the Reaction of o-Hydroxy Aryl Ketone, Amine and Chloroacetyl Chloride

Energy Technology Data Exchange (ETDEWEB)

Xia, Shuai; Wang, Xiuhua; Liu, Jiqiang; Liu, Chang; Chen, Jianbin; Zuo, Hua [Southwest Univ., Chongqing (China); Xie, Yongsheng; Dong, Wenliang; Shin, Dongsoo [Changwon National Univ., Changwon (Korea, Republic of)

2014-06-15

A facile and effective method has been developed for the synthesis of a novel series of benzofuran derivatives via N-acylation, O-alkylation and intramolecular condensation reactions, starting from readily available substituted o-hydroxy aryl ketone, and chloroacetyl arylamides. This metal-free transition process is characterized by mild reaction conditions, atom economy, short reaction time and a high yield with a decreased amount of by-products.

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

Directory of Open Access Journals (Sweden)

Grzegorz Mlostoń

2017-09-01

Full Text Available Trimethylsilyldiazomethane (TMS-CHN2 reacts readily with hetaryl thioketones to give sterically crowded 2-trimethylsilyl-4,4,5,5-tetrahetaryl-1,3-dithiolanes with complete regioselectivity at −75 °C as well as at rt. Thiofluorenone, a relatively stable and highly reactive aryl thioketone, yields upon treatment with TMS-CHN2 at −60 °C the corresponding 1,3,4-thiadiazoline. This unstable cycloadduct undergoes decomposition at ca. −45 °C and the silylated thiocarbonyl S-methanide generated thereby is trapped with complete regioselectivity by aryl or hetaryl thioketones forming also sterically crowded 2-trimethylsilyl-1,3-dithiolanes. The obtained 1,3-dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol offers a new, highly efficient approach to tetrasubstituted ethenes and dibenzofulvenes bearing aryl and/or hetaryl substituents.

Synthesis of tritium-labelled isopenicillin N, penicillin N and 6-aminopenicillanic acid

International Nuclear Information System (INIS)

Usher, J.J.; Loder, B.; Abraham, E.P.

1975-01-01

1. Phenoxymethylpenicillin sulphoxide 4-methoxybenzyl ester was labelled with 3 H in its 2-β-methyl group. Its specific radioactivity was 362mCi/mmol. 2. Removal of the side chain of this compound yielded the corresponding ester of 6-aminopenicillanic acid sulphoxide and coupling of the latter with the appropriate protected α-aminoadipic acid gave 4-methoxybenzyloxycarbonylisopenicillin N sulphoxide di-4-methoxybenzyl ester or the corresponding derivative of penicillin N. 3. Removal of the protective groups by hydrogenolysis and reduction of the sulphoxide group yielded 3 H-labelled isopenicillin N or penicillin N. 4. 3 H-labelled phenoxymethylpenicillin sulphoxide was obtained by hydrogenolysis from its 4-methoxybenzyl ester. Reducton of its sulphoxide group and subsequent removal of the side chain gave 3 H-labelled 6-aminopenicillanic acid. (author)

Sequential enzymatic synthesis and separation of 13N-L-glutamic acid and 13N-L-alanine

International Nuclear Information System (INIS)

Cohen, M.B.; Spolter, L.; MacDonald, M.; Chang, C.C.; Takahashi, J.

1975-01-01

The sequential enzymatic synthesis and separation of 13 N-L-glutamic acid and 13 N-L-alanine are described. Basically, that involves the synthesis of 13 N-L-glutamic acid by one enzyme, the transamination of the labeled glutamic acid to form 13 N-L-alanine by a second enzyme, and the separation of the two amino acids by rapid column chromatography. The 13 N-L-alanine was evaluated in animals by imaging and tissue distribution studies and showed good potential as a pancreatic imaging agent

Preparation of MIP grafts for quercetin by tandem aryl diazonium surface chemistry and photopolymerization

International Nuclear Information System (INIS)

Salmi, Zakaria; Benmehdi, Houcine; Lamouri, Aazdine; Decorse, Philippe; Jouini, Mohamed; Chehimi, Mohamed M.; Yagci, Yusuf

2013-01-01

The food antioxidant quercetin was used as a template in an ultrathin molecularly imprinted polymer (MIP) film prepared by photopolymerization. Indium tin oxide (ITO) plates were electrografted with aryl layers via a diazonium salt precursor bearing two terminal hydroxyethyl groups. The latter act as hydrogen donors for the photosensitizer isopropylthioxanthone and enabled the preparation of MIP grafts through radical photopolymerization of methacrylic acid (the functional monomer) and ethylene glycol dimethacrylate (the crosslinker) in the presence of quercetin (the template) on the ITO. The template was extracted, and the remaining ITO electrode used for the amperometric determination of quercetin at a working potential of 0.26 V (vs. SCE). The analytical range is from 5.10 −8 to 10 −4 mol L −1 , and the detection limit is 5.10 −8 mol L −1 . (author)

Synthesis, urease inhibition, antioxidant and antibacterial studies of some 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones and their 3,6-disubstituted 1,2,4-triazolo[3,4-b]1,3,4-thiadiazole derivatives

International Nuclear Information System (INIS)

Hanif, Muhammad; Saleem, Muhammad; Rama, Nasim Hasan; Hussain, Muhammad Tahir; Zaib, Sumera; Aslam, Muhammad Adil M.; Iqbal, Jamshed; Jones, Peter G.

2012-01-01

A new series of 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones, bearing various methoxybenzyl- and methoxyphenethyl groups, was synthesized by refluxing potassium hydrazinecarbodithioate salts in dilute aqueous solution of hydrazine hydrate. These salts were formed by the reaction of acid hydrazides and carbon disulfide in methanolic potassium hydroxide solution at 0-5 deg C. 4-Amino- 5-aryl-3H-1,2,4-triazole-3-thiones were condensed with different substituted aromatic acids to yield 3,6-disubstituted-1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles. The structures of the synthesized compounds were characterized by infrared (IR), 1 H and 13 C nuclear magnetic resonance (NMR), elemental analysis and mass spectrometric (MS) studies. All the synthesized compounds were screened for their urease inhibition, antioxidant and antibacterial activities. Some compounds showed excellent urease inhibition activity, more than the standard drug. Others exhibited potent antioxidant activity. All the compounds showed significant antibacterial activities as compared to the standard drug. (author)

Catalytic arylation methods from the academic lab to industrial processes

CERN Document Server

Burke, Anthony J

2014-01-01

This "hands-on" approach to the topic of arylation consolidates the body of key research over the last ten years (and up to around 2014) on various catalytic methods which involve an arylation process. Clearly structured, the chapters in this one-stop resource are arranged according to the reaction type, and focus on novel, efficient and sustainable processes, rather than the well-known and established cross-coupling methods. The entire contents are written by two authors with academic and industrial expertise to ensure consistent coverage of the latest developments in the field, as well as industrial applications, such as C-H activation, iron and gold-catalyzed coupling reactions, cycloadditions or novel methodologies using arylboron reagents. A cross-section of relevant tried-and-tested experimental protocols is included at the end of each chapter for putting into immediate practice, along with patent literature. Due to its emphasis on efficient, "green" methods and industrial applications of the products c...

Tetrahydrofuran Calpha-tetrasubstituted amino acids: two consecutive beta-turns in a crystalline linear tripeptide.

Science.gov (United States)

Maity, Prantik; Zabel, Manfred; König, Burkhard

2007-10-12

The synthesis of tetrahydrofuran Calpha-tetrasubstituted amino acids (TAAs) and their effect on the conformation in small peptides are reported. The synthesis starts from the protein amino acid methionine, which is protected at the C and N terminus and converted into the corresponding sulfonium salt by alkylation. Simple base treatment in the presence of an aryl aldehyde leads to the formation of tetrahydrofuran tetrasubstituted Calpha-amino acids in a highly diastereoselective (trans/cis ratio up to 97:3) reaction with moderate to good yields (35-78%) depending on the aldehyde used. Palladium-catalyzed coupling reactions allow a subsequent further functionalization of the TAA. The R,S,S-TAA-Ala dipeptide amide adopts a beta-turn type I conformation, whereas its S,R,S isomer does not. The R,S,S-Gly-TAA-Ala tripeptide amide shows in the solid state and in solution a conformation of two consecutive beta-turn type III structures, stabilized by i+3-->i intramolecular hydrogen bonds.

Synthesis of New N-Arylpyrimidin-2-amine Derivatives Using a Palladium Catalyst

Directory of Open Access Journals (Sweden)

So Ha Lee

2008-04-01

Full Text Available New N-aryl-4-(pyridin-3-ylpyrimidin-2-amine derivatives were synthesizedfrom the corresponding amines, applying optimized Buchwald-Hartwig aminationconditions using dichlorobis(triphenylphosphinePd(II, xantphos and sodium tertbutoxidein refluxing toluene under a nitrogen atmosphere. The target N-aryl derivativeswere obtained in moderate to good yields ranging from 27% to 82%. The proceduredescribed could be widely employed for the preparation of new heterocyclic compounds.The structures of the new compounds were confirmed by FT-NMR, FT-IR and elementalanalysis.

Synthesis, characterization and antibacterial activity of some 5-aryl-1, 3-Diphenyl 1-4, 5-dihydro-1H-Pyrazoles

International Nuclear Information System (INIS)

Al-Bahtiti, Nawal Hassan

2007-01-01

The condensation of acetophenone (I) with arylaldehyde (II) was investigated and the resulting chalcones 2-Arylidene 1-Acetophenone (III) were reacted with phenyl hydrazine and acetic acid to produce substituted 5-aryl-1, 3-diphenyl-4, 5-dihydro-1H-Pyrazoles (IV). The structures of all products were studied by H-NMR, IR, thermal and elemental analysis. Thermo-gravimetric (TG) and differential thermal analysis (DTA) was applied to investigate the thermal behavior and structure of the synthesized compounds. 2-Pyrazolines (IV) exhibited moderate activity against Streptococcus faecalis ATCC 19433, Klebsiella pneumoniae ATCC 13883, Proteus vulgaris ATCC 25922, Shigella sonnei ATCC 25931 and Peseudom oaeruginosa ATCC 27853. (author)

n-3 fatty acids reduce plasma 20-hydroxyeicosatetraenoic acid and blood pressure in patients with chronic kidney disease.

Science.gov (United States)

Barden, Anne E; Burke, Valerie; Mas, Emilie; Beilin, Lawrence J; Puddey, Ian B; Watts, Gerald F; Irish, Ashley B; Mori, Trevor A

2015-09-01

Metabolism of arachidonic acid by cytochrome P450 ω-hydroxylase leads to the formation of 20-hydroxyeicosatetraenoic acid (20-HETE) that regulates vascular function, sodium homeostasis and blood pressure (BP). Supplementation with n-3 fatty acids is known to alter arachidonic acid metabolism and reduce the formation of the lipid peroxidation products F2-isoprostanes, but the effect of n-3 fatty acids on 20-HETE has not been studied. We previously reported a significant effect of n-3 fatty acids but not coenzyme Q10 (CoQ) to reduce BP in a double-blind, placebo-controlled intervention, wherein patients with chronic kidney disease (CKD) were randomized to n-3 fatty acids (4 g), CoQ (200 mg), both supplements or control (4 g olive oil), daily for 8 weeks. This study examined the effect of n-3 fatty acids on plasma and urinary 20-HETE in the same study, as well as plasma and urinary F2-isoprostanes, and relate these to changes in BP. Seventy-four patients completed the 8-week intervention. n-3 fatty acids but not CoQ significantly reduced plasma 20-HETE (P = 0.001) and F2-isoprostanes (P fatty acids. This is the first report that n-3 fatty acid supplementation reduces plasma 20-HETE in humans and that this associates with reduced BP. These results provide a plausible mechanism for the reduction in BP observed in patients with CKD following n-3 fatty acid supplementation.

On prediction of inhibiting properties of o-aryl-carboxylates in local dissolution of iron

International Nuclear Information System (INIS)

Kuznetsov, Yu.I.; Kerbeleva, I.Ya.; Brusnikina, V.M.; Rozenfel'd, I.L.

1979-01-01

The anodic behaviour of Armco iron in the borate buffer (ph 7.4), containing sulphates as agressive anions and inhibiting substances - aryl carboxilates is studied. The possibility of using the principle of free energy linearity for quantitative prediction of protective properties of aryl carboxilates at the metal local solution is shown. The latter characterized by the pitting formation potential (phi sub(pf)), the inhibiting criterion being Δphi=phisub(pf)sup(R)-phisub(pf)sup(H). The linear correlation between Δphi and delta constants, reflecting the summary electron effects of substituent induction and mesomeric effects have been found

Lowering dietary n-6 polyunsaturated fatty acids: interaction with brain arachidonic and docosahexaenoic acids.

Science.gov (United States)

Alashmali, Shoug M; Hopperton, Kathryn E; Bazinet, Richard P

2016-02-01

Arachidonic (ARA) and docosahexaenoic (DHA) acids are the most abundant polyunsaturated fatty acids (PUFA) in the brain, where they have many biological effects, including on inflammation, cell-signaling, appetite regulation, and blood flow. The Western diet contains a high ratio of n-6: n-3 PUFA. Although interest in lowering this ratio has largely focused on increasing intake of n-3 PUFA, few studies have examined lowering dietary n-6 PUFA. This review will evaluate the effect of lowering dietary n-6 PUFA on levels and metabolism of ARA and DHA in animal models and in humans, with a primary focus on the brain. In animal models, lowering dietary ARA or linoleic acid generally lowers levels of brain ARA and raises DHA. Lowering dietary n-6 PUFA can also modulate the levels of ARA and DHA metabolizing enzymes, as well as their associated bioactive mediators. Human studies examining changes in plasma fatty acid composition following n-6 PUFA lowering demonstrate no changes in levels of ARA and DHA, though there is evidence of alterations in their respective bioactive mediators. Lowering dietary n-6 PUFA, in animal models, can alter the levels and metabolism of ARA and DHA in the brain, but it remains to be determined whether these changes are clinically meaningful.

Flax fabric reinforced arylated soy protein composites: A brittle-matrix behaviour

CSIR Research Space (South Africa)

Kumar, R

2012-05-01

Full Text Available Biocomposites were successfully prepared by the reinforcement of soy protein isolate (SPI) with different weight fractions of woven flax fabric. The flax-fabric-reinforced SPI-based composites were then arylated with 2,2-diphenyl-2-hydroxyethanoic...

One-pot, Facile Synthesis of Quinoxaline Derivatives from Bis-aryl a ...

African Journals Online (AJOL)

NICO

Bis-aryl a-Hydroxyketones and o-Arenediamines using. KMnO. 4. /CuSO. 4 ... Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174, Iran. Received 31 ... cent materials,6 organic semiconductors,7 building blocks for the synthesis of ...

Kynurenine pathway metabolism following prenatal KMO inhibition and in Mecp2+/- mice, using liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Forrest, Caroline M; Kennedy, Peter G E; Rodgers, Jean; Dalton, R Neil; Turner, Charles; Darlington, L Gail; Cobb, Stuart R; Stone, Trevor W

2016-11-01

To quantify the full range of tryptophan metabolites along the kynurenine pathway, a liquid chromatography - tandem mass spectrometry method was developed and used to analyse brain extracts of rodents treated with the kynurenine-3-mono-oxygenase (KMO) inhibitor Ro61-8048 during pregnancy. There were significant increases in the levels of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (3-HK) in the maternal brain after 5 h but not 24 h, while the embryos exhibited high levels of kynurenine, kynurenic acid and anthranilic acid after 5 h which were maintained at 24 h post-treatment. At 24 h there was also a strong trend to an increase in quinolinic acid levels (P = 0.055). No significant changes were observed in any of the other kynurenine metabolites. The results confirm the marked increase in the accumulation of some neuroactive kynurenines when KMO is inhibited, and re-emphasise the potential importance of changes in anthranilic acid. The prolonged duration of metabolite accumulation in the embryo brains indicates a trapping of compounds within the embryonic CNS independently of maternal levels. When brains were examined from young mice heterozygous for the meCP2 gene - a potential model for Rett syndrome - no differences were noted from control mice, suggesting that the proposed roles for kynurenines in autism spectrum disorder are not relevant to Rett syndrome, supporting its recognition as a distinct, independent, condition. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions.

Science.gov (United States)

Ruiz-Castillo, Paula; Buchwald, Stephen L

2016-10-12

Pd-catalyzed cross-coupling reactions that form C-N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C-N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

40 CFR 721.3821 - L-Glutamic acid, N-(1-oxododecyl)-.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false L-Glutamic acid, N-(1-oxododecyl... Substances § 721.3821 L-Glutamic acid, N-(1-oxododecyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as L-Glutamic acid, N-(1-oxododecyl)- (PMN P...

Direct arylation of benzene with aryl bromides using high-temperature/high-pressure process windows: expanding the scope of C-H activation chemistry.

Science.gov (United States)

Pieber, Bartholomäus; Cantillo, David; Kappe, C Oliver

2012-04-16

A detailed investigation on the direct arylation of benzene with aryl bromides by using first-row transition metals under high-temperature/high-pressure (high-T/p) conditions is described. By employing a parallel reactor platform for rapid reaction screening and discovery at elevated temperatures, various metal/ligand/base combinations were evaluated for their ability to enable biaryl formation through C-H activation. The combination of cobalt(III) acetylacetonate and lithium bis(trimethylsilyl)amide was subjected to further process intensification at 200 °C (15 bar), allowing a significant reduction of the catalyst/base loading and a dramatic increase in catalytic efficiency (turnover frequency) by a factor of 1000 compared to traditional protocols. The high-throughput screening additionally identified novel nickel- and copper-based metal/ligand combinations that favored an amination pathway competing with C-H activation, with the addition of ligands, such as 1,10-phenanthroline, having a profound influence on the selectivity. In addition to metal-based catalysts, high-T/p process windows were also successfully applied to transition-metal-free systems, utilizing 1,10-phenanthroline as organocatalyst. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of radiolabelled aryl azides from diazonium salts: experimental and computational results permit the identification of the preferred mechanism.

Science.gov (United States)

Joshi, Sameer M; de Cózar, Abel; Gómez-Vallejo, Vanessa; Koziorowski, Jacek; Llop, Jordi; Cossío, Fernando P

2015-05-28

Experimental and computational studies on the formation of aryl azides from the corresponding diazonium salts support a stepwise mechanism via acyclic zwitterionic intermediates. The low energy barriers associated with both transition structures are compatible with very fast and efficient processes, thus making this method suitable for the chemical synthesis of radiolabelled aryl azides.

One-step formation of bifunctionnal aryl/alkyl grafted films on conducting surfaces by the reduction of diazonium salts in the presence of alkyl iodides.

Science.gov (United States)

Hetemi, Dardan; Hazimeh, Hassan; Decorse, Philippe; Galtayries, Anouk; Combellas, Catherine; Kanoufi, Frédéric; Pinson, Jean; Podvorica, Fetah I

2015-05-19

The formation of partial perfluoroalkyl or alkyl radicals from partial perfluoroalkyl or alkyl iodides (ICH2CH2C6F13 and IC6H13) and their reaction with surfaces takes place at low driving force (∼-0.5 V/SCE) when the electrochemical reaction is performed in acetonitrile in the presence of diazonium salts (ArN2(+)), at a potential where the latter is reduced. By comparison to the direct grafting of ICH2CH2C6F13, this corresponds to a gain of ∼2.1 V in the case of 4-nitrobenzenediazonium. Such electrochemical reaction permits the modification of gold surfaces (and also carbon, iron, and copper) with mixed aryl-alkyl groups (Ar = 3-CH3-C6H4, 4-NO2-C6H4, and 4-Br-C6H4, R = C6H13 or (CH2)2-C6F13). These strongly bonded mixed layers are characterized by IRRAS, XPS, ToF-SIMS, ellipsometry, water contact angles, and cyclic voltammetry. The relative proportions of grafted aryl and alkyl groups can be varied along with the relative concentrations of diazonium and iodide components in the grafting solution. The formation of the films is assigned to the reaction of aryl and alkyl radicals on the surface and on the first grafted layer. The former is obtained from the electrochemical reduction of the diazonium salt; the latter results from the abstraction of an iodine atom by the aryl radical. The mechanism involved in the growth of the film provides an example of complex surface radical chemistry.

Acylation and metabolism of (n-6) fatty acids in hepatocytes

International Nuclear Information System (INIS)

Voss, A.C.; Sprecher, H.

1986-01-01

Isolated hepatocytes (5 x 10 6 in 2ml) from chow fed rats were incubated from 20 to 60 min. with increasing concentrations of [1- 14 C] labeled 18:2 (n-6), 18:3 (n-6) or 20:3 (n-6) to define optimum conditions for measuring acylation and metabolism to other (n-6) acids with subsequent incorporation into lipids. The triglycerides (TG) and phospholipids (PL) contained 157 and 80 nmols of 18:2 (n-6) and 6.0 and 6.1 nmols of other (n-6) acids, respectively, when cells were incubated with 0.3mM [1- 14 C] 18:2 (n-6) for 40 min. When cells were incubated with 0.3mM [1- 14 C] 18:2 (n-6) plus 0.15 to 0.45mM 18:3 (n-6) or 20:3 (n-6), the metabolism of 18:2 (n-6) to other (n-6) acids was inhibited but not totally abolished. These results may suggest that (n-6) acid made from linoleate do not totally equilibrate with exogenous 18:3 (n-6) or 20:3

Cyclohexenones Through Addition of Ethyl Acetoacetate to 3-Aryl-1 ...

African Journals Online (AJOL)

Chalcone derivatives 3a–i containing a thiophene ring were prepared by the condensation of 1-(thiophen-3-yl)ethanone with aromatic aldehydes in excellent yields. The Michael addition of ethyl acetoacetate 4 to chalcone derivatives 3a–i resulted in the formation of nine novel ethyl 6-aryl ...

N,N-Di aryl anilinosquaraines and Their Application to Organic Photovoltaics

KAUST Repository

Wang, Siyi

2011-11-08

We report new derivatives of symmetric squaraine dyes with N,N-diarylanilino substituents that have high solubility and high absorptivity (ε = 0.71-4.1 ×105 M-1cm-1) in the red solar spectral region (λmax = 645-694 nm) making them promising candidates for application in organic photovoltaics (OPVs). Unsymmetrical N,N-diisobutylanilino- and N,N-diphenylanilino(diphenylamino) squaraines have also been prepared that give blue-shifted absorption spectra (λmax = 529-535 nm) relative to their symmetric counterparts. Compared to bis(N,N-diisobutylanilino)squaraine, both symmetrical and unsymmetrical N,N-diarylanilino squaraines show markedly broader absorption bands in solution than their N,N-dialkylanilino squaraine counterparts: the full width at half-maximum (fwhm) for N,N-diarylanilino squaraines range from 1280-1980 cm-1, while the fwhm value for the N,N-diisobutylanilino squarine is only 630 cm-1. The absorption bands for thin films of N,N-diarylanilino squaraines broaden further to 2500-3300 cm-1. N,N-Diarylanilino squaraines are fluorescent, albeit with lower quantum yields than bis(N,N-diisobutylanilino)squaraine (φPL = 0.02-0.66 and 0.80, respectively). OPVs were prepared with solution processed squaraine layers using the following structure: ITO/squaraine (66-85 Å)/C60 (400 Å)/BCP (100 Å)/Al (1000 Å), BCP = bathocuproine. Devices using thin films of the bis(N,N-diarylanilino)squaraines as donor layers show improved performance relative to OPVs prepared with bis(N,N-dialkylanilino) squaraines, i.e. bis(N,N-diisobutylanilino)squaraine: open-circuit voltage Voc = 0.59 ± 0.05 V, short-circuit current Jsc = 5.58 ± 0.16 mA/cm2, fill factor FF = 0.56 ± 0.03, and power conversion efficiency η = 1.8 ± 0.2% under 1 sun, AM1.5G simulated illumination, compared with bis(N,N-diphenylanilino)squaraine: V oc = 0.82 ± 0.02 V, Jsc = 6.71 ± 0.10 mA/cm2, FF = 0.59 ± 0.01, and η = 3.2 ± 0.1%. Morphological studies of thin films suggest that the solubility of bis(N,N

N,N-Di aryl anilinosquaraines and Their Application to Organic Photovoltaics

KAUST Repository

Wang, Siyi; Hall, Lincoln; Diev, Vyacheslav V.; Haiges, Ralf; Wei, Guodan; Xiao, Xin; Djurovich, Peter I.; Forrest, Stephen R.; Thompson, Mark E.

2011-01-01

We report new derivatives of symmetric squaraine dyes with N,N-diarylanilino substituents that have high solubility and high absorptivity (ε = 0.71-4.1 ×105 M-1cm-1) in the red solar spectral region (λmax = 645-694 nm) making them promising candidates for application in organic photovoltaics (OPVs). Unsymmetrical N,N-diisobutylanilino- and N,N-diphenylanilino(diphenylamino) squaraines have also been prepared that give blue-shifted absorption spectra (λmax = 529-535 nm) relative to their symmetric counterparts. Compared to bis(N,N-diisobutylanilino)squaraine, both symmetrical and unsymmetrical N,N-diarylanilino squaraines show markedly broader absorption bands in solution than their N,N-dialkylanilino squaraine counterparts: the full width at half-maximum (fwhm) for N,N-diarylanilino squaraines range from 1280-1980 cm-1, while the fwhm value for the N,N-diisobutylanilino squarine is only 630 cm-1. The absorption bands for thin films of N,N-diarylanilino squaraines broaden further to 2500-3300 cm-1. N,N-Diarylanilino squaraines are fluorescent, albeit with lower quantum yields than bis(N,N-diisobutylanilino)squaraine (φPL = 0.02-0.66 and 0.80, respectively). OPVs were prepared with solution processed squaraine layers using the following structure: ITO/squaraine (66-85 Å)/C60 (400 Å)/BCP (100 Å)/Al (1000 Å), BCP = bathocuproine. Devices using thin films of the bis(N,N-diarylanilino)squaraines as donor layers show improved performance relative to OPVs prepared with bis(N,N-dialkylanilino) squaraines, i.e. bis(N,N-diisobutylanilino)squaraine: open-circuit voltage Voc = 0.59 ± 0.05 V, short-circuit current Jsc = 5.58 ± 0.16 mA/cm2, fill factor FF = 0.56 ± 0.03, and power conversion efficiency η = 1.8 ± 0.2% under 1 sun, AM1.5G simulated illumination, compared with bis(N,N-diphenylanilino)squaraine: V oc = 0.82 ± 0.02 V, Jsc = 6.71 ± 0.10 mA/cm2, FF = 0.59 ± 0.01, and η = 3.2 ± 0.1%. Morphological studies of thin films suggest that the solubility of bis(N,N

Synthesis of 3-Phenyl-4[4-(m-nitrophenyl-N-2-(2’-arylureido / arylthioureido-4’-N-morpholino-s-triazin-benzo-[6,7]-coumarins and their Applicatiions

Directory of Open Access Journals (Sweden)

J. P. Raval

2004-01-01

Full Text Available Several 3 – phenyl – 4 [4-(m – nitrophenyl – N – 2 - (2’-arylureido /arylthioureido - 4’- N -morpholino-s-triazin-benzo-(6,7-coumarins were prepared using 2-(m–nitrophenyl-3-hydroxy naphthalene, cyanuric chloride, morpholine and various aryl – ureas / aryl – thioureas derivatives to give desired compound. The structures of the compounds were confirmed by elemental analysis and spectral analysis. The antibacterial activities of these compounds have been screened and were also applied as Flourescent Brighteners on Polyester fabrics.

Formation of aryl-chlorinated aromatic acids and precursors for chloroform in chlorination of humic acid

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Leer, E.W.B. de; Galan, L.

1985-01-01

The formation of chloroform when humic substances are chlorinated is well known. Other chlorinated products that may be formed are chloral, di- and trichloroacetic acid, chlorinated C-4 diacids, and α-chlorinated aliphatic acids. Several of these compounds are formed in molar yields comparable

2-ARYL-6,8-DIBROMO-2,3-DIHYDROQUINAZOLIN-4(1H)

African Journals Online (AJOL)

Preferred Customer

The first task in this investigation was to synthesize the requisite 2-aryl-6 .... carbonate as a base in aqueous DMF at 120 °C. We isolated after 2 h by ..... cool to room temperature and then quenched with saturated sodium thiosulfate solution.

Aryl hydrocarbon receptor ligand effects in RBL2H3 cells

DEFF Research Database (Denmark)

Maaetoft-Udsen, Kristina; Shimoda, Lori M. N.; Frøkiær, Hanne

2012-01-01

The aryl hydrocarbon receptor (AHR) mediates toxic effects of dioxin and xenobiotic metabolism. AHR has an emerging role in the immune system, but its physiological ligands and functional role in immunocytes remain poorly understood. Mast cells are immunocytes that are central to inflammatory...

Aryl diazonium salts: a new class of coupling agents for bonding polymers, biomacromolecules and nanoparticles to surfaces.

Science.gov (United States)

Mahouche-Chergui, Samia; Gam-Derouich, Sarra; Mangeney, Claire; Chehimi, Mohamed M

2011-07-01

This critical review summarizes existing knowledge on the use of diazonium salts as a new generation of surface modifiers and coupling agents for binding synthetic polymers, biomacromolecules, and nanoparticles to surfaces. Polymer grafts can be directly grown at surfaces through the so-called grafting from approaches based on several polymerization methods but can also be pre-formed in solution and then grafted to surfaces through grafting onto strategies including "click" reactions. Several routes are also described for binding biomacromolecules through aryl layers in view of developing biosensors and protein arrays, while the use of aryl diazonium coupling agents is extended to the attachment of nanoparticles. Patents and industrial applications of the surface chemistry of diazonium compounds are covered. This review stresses the paramount role of aryl diazonium coupling agents in adhesion, surface and materials sciences (114 references).

Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A

International Nuclear Information System (INIS)

Mallinger, A.

2008-11-01

When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A

15N NMR spectroscopic investigation of nitrous and nitric acids in sulfuric acid solutions of varying acidities

International Nuclear Information System (INIS)

Prakash, G.K.S.; Heiliger, L.; Olah, G.A.

1990-01-01

Both nitrous and nitric acids were studied in sulfuric acid solutions of varying acid strengths by 15 N NMR spectroscopy. The study gives new insights into the nature of intermediates present at different acid strengths. Furthermore, we have also discovered a novel redox reaction between NO 2 + and NO + ions involving the intermediacy of their respective acids. A mechanism is proposed to explain the observed results. 13 refs., 2 figs., 1 tab

Analytical applications of N-phenyl-n-butyro hydroxamic and N-p-tolyl-n-butyro hydroxamic acids towards chromium (VI), copper (II), iron (III) and uranium (VI)

International Nuclear Information System (INIS)

Elkhadir, A. Y. F.

2001-05-01

Two aliphatic hydroxamic acids were prepared; N-phenyl-n-butyro hydroxamic acid and N-p-tolyl-n-butyro hydroxamic acid, by the reaction of β-phenylhydroxylamine and p-tolyl hydroxylamine with n-butyryl chloride. The acids were identified by: their melting points, characteristic reactions with acidic solutions of vanadium (V) and iron (III), infrared spectroscopy, nitrogen content and molecular weight determination. The extractability of these acids towards Cr (VI), Cu (II), Fe (III) and U (VI) were investigated at different pH values and molar acid concentrations. N-phenyl-n- butyro hydroxamic acid has a maximum extraction (98.80%) for Cr (VI) at 4 M H 2 SO 4 , (83.25%) for Cu (II) at pH 6, (99.17%) for Fe (III) at pH 5 and (99.76%) at 4 M HNO 3 for U (VI) respectively. N-p-tolyl-n-butyro hydroxamic acid has a maximum extraction (98.40%) for Cr (VI)at 4 M H 2 SO 4 , (81.30%) for Cu (II) at pH 6, (92.80%) for Fe (III) at pH 5 and (99.64%) for U (VI) at 4 M HNO 3 , respectively. The ratios of the metal to ligands were determined by job method (continuous variation method) and were found to be 1:2 for Cr (VI) and U (VI). (Author)

Analytical applications of N-phenyl-n-butyro hydroxamic and N-p-tolyl-n-butyro hydroxamic acids towards chromium (VI), copper (II), iron (III) and uranium (VI)

Energy Technology Data Exchange (ETDEWEB)

Elkhadir, A Y. F. [Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum (Sudan)

2001-05-01

Two aliphatic hydroxamic acids were prepared; N-phenyl-n-butyro hydroxamic acid and N-p-tolyl-n-butyro hydroxamic acid, by the reaction of {beta}-phenylhydroxylamine and p-tolyl hydroxylamine with n-butyryl chloride. The acids were identified by: their melting points, characteristic reactions with acidic solutions of vanadium (V) and iron (III), infrared spectroscopy, nitrogen content and molecular weight determination. The extractability of these acids towards Cr (VI), Cu (II), Fe (III) and U (VI) were investigated at different pH values and molar acid concentrations. N-phenyl-n- butyro hydroxamic acid has a maximum extraction (98.80%) for Cr (VI) at 4 M H{sub 2}SO{sub 4}, (83.25%) for Cu (II) at pH 6, (99.17%) for Fe (III) at pH 5 and (99.76%) at 4 M HNO{sub 3} for U (VI) respectively. N-p-tolyl-n-butyro hydroxamic acid has a maximum extraction (98.40%) for Cr (VI)at 4 M H{sub 2} SO{sub 4}, (81.30%) for Cu (II) at pH 6, (92.80%) for Fe (III) at pH 5 and (99.64%) for U (VI) at 4 M HNO{sub 3}, respectively. The ratios of the metal to ligands were determined by job method (continuous variation method) and were found to be 1:2 for Cr (VI) and U (VI). (Author)

N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

International Nuclear Information System (INIS)

Rosenspire, K.C.; Gelbard, A.S.

1986-01-01

With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

Evaluation of sup(99m)Tc labeled amino acids as radiopharmaceuticals, 4. S-substituted cysteines and N-substituted iminodiacetic acids

Energy Technology Data Exchange (ETDEWEB)

Karube, Yoshiharu; Maeda, Tatsuo; Ohya, Masato; Sugata, Setsuro; Kono, Akira (Kyushu Cancer Center Research Inst., Fukuoka (Japan)); Matsushima, Yoshikazu

1982-06-01

Sixteen sup(99m)Tc labeled ligands were evaluated as scintigraphic agents. The ligands studied were cysteine, glutathione, their S-substituted derivatives, lysine-N sup(epsilon), N sup(epsilon)-diacetic acid, glycylglycine-N,N-diacetic acid, glycylglycylglycine-N,N-diacetic acid, taurine-N,N-diacetic acid, hydrazine-N,N-diacetic acid, ethylenediamine-N,N-diacetic acid, and propylne-1,3-diamine-N/sup 1/-,N/sup 1/-diacetic acid. The ligands were labeled with sup(99m)Tc by the SnCl/sub 2/ method with more than 95% yield. The in vivo behavior of the sup(99m)Tc labeled ligands were studied in golden hamsters and dogs. The organ distribution in golden hamsters indicated clearance both by hepatobiliary and renal systems. The pancreas/blood ratios were much lower in the sup(99m)Tc ligands than in /sup 75/Se-selenomethionine. Scintigraphic studies in dogs showed that the liver and kidneys were well visualized but the accumulation by the pancreas was not sufficient for clear visualization.

Aryl hydrocarbon receptor-dependent up-regulation of the heterodimeric amino acid transporter LAT1 (SLC7A5)/CD98hc (SLC3A2) by diesel exhaust particle extract in human bronchial epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Le Vee, Marc; Jouan, Elodie; Lecureur, Valérie [Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes (France); Fardel, Olivier, E-mail: olivier.fardel@univ-rennes1.fr [Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes (France); Pôle Biologie, Centre Hospitalier Universitaire, 2 rue Henri Le Guilloux, 35033 Rennes (France)

2016-01-01

The heterodimeric L-type amino acid transporter (LAT) 1/CD98hc is overexpressed in lung cancers with a poor prognosis factor. Factors that contribute to LAT1/CD98hc overexpression in lung cells remain however to be determined, but the implication of atmospheric pollution can be suspected. The present study was therefore designed to analyze the effects of diesel exhaust particle (DEP) extract (DEPe) on LAT1/CD98hc expression in bronchial epithelial BEAS-2B cells. Exposure to DEPe up-regulated LAT1 and CD98hc mRNA levels in a concentration-dependent manner, with DEPe EC{sub 50} values (around 0.2 μg/mL) relevant to environmental situations. DEPe concomitantly induced LAT1/CD98hc protein expression and LAT1-mediated leucine accumulation in BEAS-2B cells. Inhibition of the aryl hydrocarbon receptor (AhR) pathway through the use of a chemical AhR antagonist or the siRNA-mediated silencing of AhR expression was next found to prevent DEPe-mediated induction of LAT1/CD98hc, indicating that this regulation depends on AhR, known to be activated by major chemical DEP components like polycyclic aromatic hydrocarbons. DEPe exposure was finally shown to induce mRNA expression and activity of matrix metalloproteinase (MMP)-2 in BEAS-2B cells, in a CD98hc/focal adhesion kinase (FAK)/extracellular regulated kinase (ERK) manner, thus suggesting that DEPe-mediated induction of CD98hc triggers activation of the integrin/FAK/ERK signaling pathway known to be involved in MMP-2 regulation. Taken together, these data demonstrate that exposure to DEPe induces functional overexpression of the amino acid transporter LAT1/CD98hc in lung cells. Such a regulation may participate to pulmonary carcinogenic effects of DEPs, owing to the well-documented contribution of LAT1 and CD98hc to cancer development. - Highlights: • The amino acid transporter LAT1/CD98hc is up-regulated in DEPe-treated lung cells. • The aryl hydrocarbon receptor is involved in DEPe-triggered induction of LAT1/CD98hc. �

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

tetrahydroquinolino[2′,3′:8,7] cyclooct[]indole analogues has been developed by reaction of 1-oxo-1,2,3,4,5,6-hexahydrocyclooct[]indole with anthranilic acid and 3-amino pyrazine acid under POCl3 condition and the synthesis of 7,8,9 ...

Influence of Rice Seeding Rate on Efficacies of Neonicotinoid and Anthranilic Diamide Seed Treatments against Rice Water Weevil

Directory of Open Access Journals (Sweden)

Jason Hamm

2014-12-01

Full Text Available Rice in the U.S. is frequently seeded at low rates and treated before sowing with neonicotinoid or anthranilic diamide insecticides to target the rice water weevil. A previous study of the influence of seeding rate on rice water weevil densities showed an inverse relationship between seeding rates and immature weevil densities. This study investigated interactive effects of seeding rate and seed treatment on weevil densities and rice yields; in particular, experiments were designed to determine whether seed treatments were less effective at low seeding rates. Four experiments were conducted over three years by varying seeding rates of rice treated at constant per seed rates of insecticide. Larval suppression by chlorantraniliprole was superior to thiamethoxam or clothianidin, and infestations at low seeding rates were up to 47% higher than at high seeding rates. Little evidence was found for the hypothesis that seed treatments are less effective at low seeding rates; in only one of four experiments was the reduction in weevil densities by thiamethoxam greater at high than at low seeding rates. However, suppression of larvae by neonicotinoid seed treatments in plots seeded at low rates was generally poor, and caution must be exercised when using the neonicotioids at low seeding rates.

Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C−O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination

KAUST Repository

Liu, Xiangqian

2016-04-10

In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting β-hydride elimination. This new nickel-catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process.

Synthesis and antimicrobial evaluation of new 3-alkyl/aryl-2-[((alpha,alpha-diphenyl-alpha-hydroxy)acetyl)hydrazono]-5-methyl-4-thiazolidinones.

Science.gov (United States)

Güzeldemirci, Nuray Ulusoy; Ilhan, Eser; Küçükbasmaci, Omer; Satana, Dilek

2010-01-01

New 4-thiazolidinone derivatives of benzilic acid (alpha,alpha-diphenyl-alpha-hydroxyacetic acid) have been synthesized and evaluated for antibacterial and antifungal activities. The reaction of 1- (alpha,alpha-diphenyl-alpha-hydroxy)acetyl-4-alkyl/arylthiosemicarbazides with ethyl 2-bromopropionate gave 3-alkyl/aryl-2-[((alpha,alpha-diphenyl-alpha-hydroxy)acetyl)hydrazono]-5-methyl-4-thiazolidinone derivatives. Their antibacterial and antifungal activities were evaluated against S. aureus ATCC 29213, P. aeruginosa ATCC 27853, E. coli ATCC 25922, C. albicans ATCC 10231, C. parapsilosis ATCC 22019, C. krusei ATCC 6258, T. mentagrophytes var. erinacei NCPF 375, M. gypseum NCPF 580 and T. tonsurans NCPF 245. 3e, 3f, 3g and 3h showed the highest antibacterial activity. Particularly 3a and 3e showed the highest antifungal activities against C. parapsilosis ATCC 22019, T. tonsurans NCPF 245 and M. gypseum NCPF 580.

Synthesis of Fluorescent 2-Substituted 6-(Het)aryl-7-deazapurine Bases {4-(Het)aryl-pyrrolo[2,3-d]pyrimidines} by Aqueous Suzuki-Miyaura Cross-Coupling Reactions

Czech Academy of Sciences Publication Activity Database

Sabat, Nazarii; Nauš, Petr; Matyašovský, Ján; Dziuba, Dmytro; Poštová Slavětínská, Lenka; Hocek, Michal

2016-01-01

Roč. 48, č. 7 (2016), s. 1029-1045 ISSN 0039-7881 R&D Projects: GA ČR GAP207/11/0344 Institutional support: RVO:61388963 Keywords : nucleobases * deazapurines * pyrrolo[2,3-d]pyrimidines * Suzuki cross - coupling * arylation Subject RIV: CC - Organic Chemistry Impact factor: 2.650, year: 2016

Immunoregulatory and anti-inflammatory effects of n-3 polyunsaturated fatty acids

Directory of Open Access Journals (Sweden)

P.C. Calder

1998-04-01

Full Text Available 1. Fish oils are rich in the long-chain n-3 polyunsaturated fatty acids (PUFAs, eicosapentaenoic (20:5n-3 and docosahexaenoic (22:6n-3 acids. Linseed oil and green plant tissues are rich in the precursor fatty acid, a-linolenic acid (18:3n-3. Most vegetable oils are rich in the n-6 PUFA linoleic acid (18:2n-6, the precursor of arachidonic acid (20:4n-6. 2. Arachidonic acid-derived eicosanoids such as prostaglandin E2 are pro-inflammatory and regulate the functions of cells of the immune system. Consumption of fish oils leads to replacement of arachidonic acid in cell membranes by eicosapentaenoic acid. This changes the amount and alters the balance of eicosanoids produced. 3. Consumption of fish oils diminishes lymphocyte proliferation, T-cell-mediated cytotoxicity, natural killer cell activity, macrophage-mediated cytotoxicity, monocyte and neutrophil chemotaxis, major histocompatibility class II expression and antigen presentation, production of pro-inflammatory cytokines (interleukins 1 and 6, tumour necrosis factor and adhesion molecule expression. 4. Feeding laboratory animals fish oil reduces acute and chronic inflammatory responses, improves survival to endotoxin and in models of autoimmunity and prolongs the survival of grafted organs. 5. Feeding fish oil reduces cell-mediated immune responses. 6. Fish oil supplementation may be clinically useful in acute and chronic inflammatory conditions and following transplantation. 7. n-3 PUFAs may exert their effects by modulating signal transduction and/or gene expression within inflammatory and immune cells.

One-pot four-component synthesis of 2-aryl-3,3-dihaloacrylonitriles using potassium hexacyanoferrate(II) as environmentally benign cyanide source

International Nuclear Information System (INIS)

Zhao, Zhouxing; Li, Zheng

2011-01-01

An efficient route to one-pot four-component reactions of aroyl chlorides, potassium hexacyanoferrate(II), triphenylphosphine and carbon tetrahalides to synthesize 2-aryl-3,3-dichloroacrylonitriles and 2-aryl-3,3-dibromoacrylonitriles was described. This protocol has advantages of use of non-toxic cyanide source, high yield and simple work-up procedure. (author)

Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis.

Science.gov (United States)

Krokhin, O V; Kuzina, O V; Hoshino, H; Shpigun, O A; Yotsuyanagi, T

2000-08-25

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal-HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40,000-400,000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(H), Fe(II) ions in reaction with HBED have been discussed.

Aryl Diazonium Chemistry for the Surface Functionalization of Glassy Biosensors.

Science.gov (United States)

Zheng, Wei; van den Hurk, Remko; Cao, Yong; Du, Rongbing; Sun, Xuejun; Wang, Yiyu; McDermott, Mark T; Evoy, Stephane

2016-03-14

Nanostring resonator and fiber-optics-based biosensors are of interest as they offer high sensitivity, real-time measurements and the ability to integrate with electronics. However, these devices are somewhat impaired by issues related to surface modification. Both nanostring resonators and photonic sensors employ glassy materials, which are incompatible with electrochemistry. A surface chemistry approach providing strong and stable adhesion to glassy surfaces is thus required. In this work, a diazonium salt induced aryl film grafting process is employed to modify a novel SiCN glassy material. Sandwich rabbit IgG binding assays are performed on the diazonium treated SiCN surfaces. Fluorescently labelled anti-rabbit IgG and anti-rabbit IgG conjugated gold nanoparticles were used as markers to demonstrate the absorption of anti-rabbit IgG and therefore verify the successful grafting of the aryl film. The results of the experiments support the effectiveness of diazonium chemistry for the surface functionalization of SiCN surfaces. This method is applicable to other types of glassy materials and potentially can be expanded to various nanomechanical and optical biosensors.

Aryl Diazonium Chemistry for the Surface Functionalization of Glassy Biosensors

Directory of Open Access Journals (Sweden)

Wei Zheng

2016-03-01

Full Text Available Nanostring resonator and fiber-optics-based biosensors are of interest as they offer high sensitivity, real-time measurements and the ability to integrate with electronics. However, these devices are somewhat impaired by issues related to surface modification. Both nanostring resonators and photonic sensors employ glassy materials, which are incompatible with electrochemistry. A surface chemistry approach providing strong and stable adhesion to glassy surfaces is thus required. In this work, a diazonium salt induced aryl film grafting process is employed to modify a novel SiCN glassy material. Sandwich rabbit IgG binding assays are performed on the diazonium treated SiCN surfaces. Fluorescently labelled anti-rabbit IgG and anti-rabbit IgG conjugated gold nanoparticles were used as markers to demonstrate the absorption of anti-rabbit IgG and therefore verify the successful grafting of the aryl film. The results of the experiments support the effectiveness of diazonium chemistry for the surface functionalization of SiCN surfaces. This method is applicable to other types of glassy materials and potentially can be expanded to various nanomechanical and optical biosensors.

Silicon dioxide surfaces with aryl interaction sites for chromatographic applications

International Nuclear Information System (INIS)

Gadzal-Kopciuch, R.; Kluska, M.; Welniak, M.; Buszewski, B.

2005-01-01

The paper presents the results of a study on aryl phases aimed at the increase of the separation selectivity of substances containing π electrons, and improving the reproducibility of retention data. The above phases contain not only a carbon chain of a different length, linking them to the support, but also one or two aromatic rings. The suitability of the newly obtained packings for the purposes of high-performance liquid chromatography was verified on the basis of a description of surface topography before and after the modification process. Various physicochemical methods were employed to determine the effectiveness of chemical modification, i.e., elemental analysis, infrared spectroscopy, and nuclear magnetic resonance. The aryl packings obtained were used for the separation of polynuclear aromatic hydrocarbons and budesonide epimers, tested under hydroorganic conditions (water/ethanol, water/methanol, water/acetonitrile). The application of a methanol/water mobile phase and a new-generation naphthylpropyl stationary phase for the separation of the 22R and 22S diastereoisomers of budesonide allowed the obtention of reproducible results and make qualitative and quantitative determinations of particular enantiomers

A unified approach for the synthesis of symmetrical and unsymmetrical dibenzyl ethers from aryl aldehydes through reductive etherification

Directory of Open Access Journals (Sweden)

J. Sembian Ruso

2016-05-01

Full Text Available In this paper, we describe a simple and convenient conversion of aryl aldehydes to symmetrical dibenzyl ethers through reductive etherification. Similarly, unsymmetrical dibenzyl ether was obtained from aryl aldehyde and TES-protected benzyl alcohol. Triethyl silane with catalytic amount of InCl3 was found to be an efficient condition for the reductive etherification. Moreover, it exhibits remarkable functional group compatibility with yield ranging from good to excellent.

A Base Promoted Synthesis of N,N-dimethylformamidines

International Nuclear Information System (INIS)

Li, Bao Lin; Ding, Si Yi; Ren, Yu Fei; Wang, Liu Chang; Jia, Yu Cai; Zhang, Xi Quan; Gu, Hong Mei

2013-01-01

In conclusion, this report supplies a base promoted synthesis of N'-aryl-N,N-dimethylformamidines straight from arylamines bearing strong electron withdrawing group at o-position and imine complex from DMF and Me 2 SO 4 . The key advantage of the procedure is to avoid the preparation of N,N-dimethylformamide dimethyl acetal from DMF and Me 2 SO 4 . Using this method, some important intermediates shown as entry 1-4, 9-11 in Table 3 were efficiently prepared. With these intermediates in hand, various antitumor drugs containing quinazoline moiety such as gefitinib, erlotinib and lapatinib etc. can be synthesized conveniently

Understanding the properties of chitosan aryl substituted thioureas in their role and potential as antibacterial agents

Science.gov (United States)

Khairul, Wan M.; Daud, Adibah Izzati; Ismail, Noraznawati

2018-02-01

In this study, the effort was to design and synthesize a series of thiourea-chitosan derivatives featuring five aryl substituted members namely N-chitosan-N'-(4-nitrobenzoyl) thiourea (1), N-chitosan-N'-(4-chlorobenzoyl) thiourea (2), N-chitosan-N'-(4-methylbenzoyl) thiourea (3), N-chitosan-N'-(2-iodobenzoyl) thiourea (4), and N-chitosan-N'-(2-methylbenzoyl) thiourea (5) via SN2 reaction pathway having different donating and withdrawing groups. Their molecular structures were then characterised by FT-IR, UV-Vis, and thermogravimetric analysis (TGA). The antimicrobial activities of these derivatives against four species bacteria Bacillus cereus, Staphylococcus aureus, Salmonella typhi, and Escherichia coli of both Gram-positive and Gram-negative type bacteria at minimum concentration 6mg/ml were carried out to investigate their potential as antibacterial agents. Compound 1 exhibited specific activity as it can only inhibit Gram-positive bacteria while other compounds 2-5 showed broad range spectrum activity as they were able to inhibit both Gram-positive and Gram-negative bacteria. Therefore, 1-5 showed good antibacterial activity and have high potential to be further developed as active materials in pharmaceutical interests.

Effects of carboxylic acids on nC60 aggregate formation

International Nuclear Information System (INIS)

Chang Xiaojun; Vikesland, Peter J.

2009-01-01

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

Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry

Science.gov (United States)

Ryder, Christopher R.; Wood, Joshua D.; Wells, Spencer A.; Yang, Yang; Jariwala, Deep; Marks, Tobin J.; Schatz, George C.; Hersam, Mark C.

2016-06-01

Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)—a layered two-dimensional semiconductor—exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.

5'Azido-N-1-napthylphthalamic acid, a photolabile analog of N-1-naphthylphthalamic acid

International Nuclear Information System (INIS)

Voet, J.G.; Howley, K.S.; Shumsky, J.S.

1987-01-01

A photolabile analog of N-1-naphthylphthalamic acid (NPA), 5'-azido-N-1-naphthylphthalamic acid (Az-NPA), has been synthesized and characterized. This potential photoaffinity label for the plasma membrane NPA binding protein competes with [ 3 H]NPA for binding sites on Curcurbita pepo L. (zucchini) hypocotyl cell membranes with K/sub 0.5/ = 2.8 x 10 -7 molar. The K/sub 0.5/ for NPA under these conditions is 2 x 10 -8 molar, indicating that the affinity of Az-NPA for the membranes is only 14-fold lower than NPA. While the binding of Az-NPA to NPA binding sites is reversible in the dark, exposure of the Az-NPA treated membranes to light results in a 30% loss in [ 3 H]NPA binding ability. Pretreatment of the membranes with NPA protects the membranes against photodestruction of [ 3 H]NPA binding sites by Az-NPA supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment

Evodiamine as a novel antagonist of aryl hydrocarbon receptor

International Nuclear Information System (INIS)

Yu, Hui; Tu, Yongjiu; Zhang, Chun; Fan, Xia; Wang, Xi; Wang, Zhanli; Liang, Huaping

2010-01-01

Research highlights: → Evodiamine interacted with the AhR. → Evodiamine inhibited the specific binding of [ 3 H]-TCDD to the AhR. → Evodiamine acts as an antagonist of the AhR. -- Abstract: Evodiamine, the major bioactive alkaloid isolated from Wu-Chu-Yu, has been shown to interact with a wide variety of proteins and modify their expression and activities. In this study, we investigated the interaction between evodiamine and the aryl hydrocarbon receptor (AhR). Molecular modeling results revealed that evodiamine directly interacted with the AhR. Cytosolic receptor binding assay also provided the evidence that evodiamine could interact with the AhR with the K i value of 28.4 ± 4.9 nM. In addition, we observed that evodiamine suppressed the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced nuclear translocation of the AhR and the expression of CYP1A1 dose-dependently. These results suggested that evodiamine was able to bind to the AhR as ligand and exhibit antagonistic effects.

Biosynthesis of N-glycolyneuraminic acid. The primary site of hydroxylation of N-acetylneuraminic acid is the cytosolic sugar nucleotide pool

Energy Technology Data Exchange (ETDEWEB)

Muchmore, E.A.; Milewski, M.; Varki, A.; Diaz, S. (San Diego Veterans Administration Medical Center, CA (USA))

1989-12-05

N-Glycolylneuraminic acid (Neu5Gc) is an oncofetal antigen in humans and is developmentally regulated in rodents. We have explored the biology of N-acetylneuraminic acid hydroxylase, the enzyme responsible for conversion of the parent sialic acid, N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. We show that the major sialic acid in all compartments of murine myeloma cell lines is Neu5Gc. Pulse-chase analysis in these cells with the sialic acid precursor (6-3H)N-acetylmannosamine demonstrates that most of the newly synthesized Neu5Gc appears initially in the cytosolic low-molecular weight pool bound to CMP. The percentage of Neu5Gc on membrane-bound sialic acids closely parallels that in the CMP-bound pool at various times of chase, whereas that in the free sialic acid pool is very low initially, and rises only later during the chase. This implies that conversion from Neu5Ac to Neu5Gc occurs primarily while Neu5Ac is in its sugar nucleotide form. In support of this, the hydroxylase enzyme from a variety of tissues and cells converted CMP-Neu5Ac to CMP-Neu5Gc, but showed no activity towards free or alpha-glycosidically bound Neu5Ac. Furthermore, the majority of the enzyme activity is found in the cytosol. Studies with isolated intact Golgi vesicles indicate that CMP-Neu5Gc can be transported and utilized for transfer of Neu5Gc to glycoconjugates. The general properties of the enzyme have also been investigated. The Km for CMP-Neu5Ac is in the range of 0.6-2.5 microM. No activity can be detected against the beta-methylglycoside of Neu5Ac. On the other hand, inhibition studies suggest that the enzyme recognizes both the 5'-phosphate group and the pyrimidine base of the substrate. Taken together, the data allow us to propose pathways for the biosynthesis and reutilization of Neu5Gc.

Prevention of melanin formation during aryl alcohol oxidase production under growth-limited conditions using an Aspergillus nidulans cell factory.

Science.gov (United States)

Pardo-Planas, Oscar; Prade, Rolf A; Müller, Michael; Atiyeh, Hasan K; Wilkins, Mark R

2017-11-01

An Aspergillus nidulans cell factory was genetically engineered to produce an aryl alcohol oxidase (AAO). The cell factory initiated production of melanin when growth-limited conditions were established using stationary plates and shaken flasks. This phenomenon was more pronounced when the strain was cultured in a trickle bed reactor (TBR). This study investigated different approaches to reduce melanin formation in fungal mycelia and liquid medium in order to increase the enzyme production yield. Removal of copper from the medium recipe reduced melanin formation in agar cultures and increased enzyme activities by 48% in agitated liquid cultures. Copper has been reported as a key element for tyrosinase, an enzyme responsible for melanin production. Ascorbic acid (0.44g/L) stopped melanin accumulation, did not affect growth parameters and resulted in AAO activity that was more than two-fold greater than a control treatment with no ascorbic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uranium (IV) carboxylates - I

Energy Technology Data Exchange (ETDEWEB)

Satpathy, K C; Patnaik, A K [Sambalpur Univ. (India). Dept. of Chemistry

1975-11-01

A few uranium(IV) carboxylates with monochloro and trichloro acetic acid, glycine, malic, citric, adipic, o-toluic, anthranilic and salicylic acids have been prepared by photolytic methods. The I.R. spectra of these compounds are recorded and basing on the spectral data, structure of the compounds have been suggested.

Synthesis of polyanthranilic acid–Au nanocomposites by emulsion ...

Indian Academy of Sciences (India)

Polyanthranilic acid (PANA) and polyanthranilic acid–gold (PANA–Au) nanocomposites have been synthesized through emulsion polymerization technique. Use of gold chloride as an oxidant for anthranilic acid not only provides a new route for chemical synthesis of PANA, but also explores a facile method for the formation ...

Bioassay directed identification of natural aryl hydrocarbon-receptor agonists in marmalade

NARCIS (Netherlands)

Ede, van K.I.; Li, A.; Antunes Fernandes, E.C.; Mulder, P.P.J.; Peijnenburg, A.A.C.M.; Hoogenboom, L.A.P.

2008-01-01

Citrus fruit and citrus fruit products, like grapefruit, lemon and marmalade were shown to contain aryl hydrocarbon receptor (AhR) agonists, as detected with the DR CALUX® bioassay. This is of interest regarding the role of the Ah-receptor pathway in the adverse effects of dioxins, PCBs and other

Ru/Me-BIPAM-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes and α-Ketoesters

Directory of Open Access Journals (Sweden)

Momoko Watanabe

2011-06-01

Full Text Available A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(arylmethanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM achieved excellent enantioselectivities.

Structural changes of corn stover lignin during acid pretreatment.

Science.gov (United States)

Moxley, Geoffrey; Gaspar, Armindo Ribeiro; Higgins, Don; Xu, Hui

2012-09-01

In this study, raw corn stover was subjected to dilute acid pretreatments over a range of severities under conditions similar to those identified by the National Renewable Energy Laboratory (NREL) in their techno-economic analysis of biochemical conversion of corn stover to ethanol. The pretreated corn stover then underwent enzymatic hydrolysis with yields above 70 % at moderate enzyme loading conditions. The enzyme exhausted lignin residues were characterized by ³¹P NMR spectroscopy and functional moieties quantified and correlated to enzymatic hydrolysis yields. Results from this study indicated that both xylan solubilization and lignin degradation are important for improving the enzyme accessibility and digestibility of dilute acid pretreated corn stover. At lower pretreatment temperatures, there is a good correlation between xylan solubilization and cellulose accessibility. At higher pretreatment temperatures, lignin degradation correlated better with cellulose accessibility, represented by the increase in phenolic groups. During acid pretreatment, the ratio of syringyl/guaiacyl functional groups also gradually changed from less than 1 to greater than 1 with the increase in pretreatment temperature. This implies that more syringyl units are released from lignin depolymerization of aryl ether linkages than guaiacyl units. The condensed phenolic units are also correlated with the increase in pretreatment temperature up to 180 °C, beyond which point condensation reactions may overtake the hydrolysis of aryl ether linkages as the dominant reactions of lignin, thus leading to decreased cellulose accessibility.

N-3 polyunsaturated fatty acids, body fat and inflammation

DEFF Research Database (Denmark)

Lund, Anne-Sofie Quist; Hasselbalch, Ann Louise; Gamborg, Michael

2013-01-01

BACKGROUND: Based on animal studies, n-3 polyunsaturated fatty acids (PUFAs) have been suggested to lower the risk of obesity and inflammation. We aimed to investigate if, among humans, intake of n-3 PUFAs was associated with i) total body fat, ii) body fat distribution and iii) obesity...... in relation to outcomes were performed and adjusted for potential confounders. RESULTS: Absolute n-3 PUFA intake, but not n-3/n-6, was inversely associated with the different measures of body fat. Among n-3 PUFA derivatives, only α-linolenic acid (ALA) was inversely associated with body fat measures...

Can long chain n-3 fatty acids from feed be converted into very long chain n-3 fatty acids in fillets from farmed rainbow trout (Oncorhynchus mykiss)?

Science.gov (United States)

Lušnic Polak, M.; Demšar, L.; Luzar, U.; Polak, T.

2017-09-01

The link between the basic chemical and fatty acid composition of trout feed on one hand and trout (Oncorhynchus mykiss) meat (fillet) was investigated.. The content of 52 fatty acids from feed and trout meat lipids was determined by in-situ transesterification and capillary column gas-liquid chromatography. On average, 100 g of trout feed contained 7.4 g of moisture, 47.7 g of proteins, 6.09 g of ash, 21.4 g of fat, and as for fatty acid composition, 47.8 wt. % were monounsaturated, 34.0 wt. % were polyunsaturated and 18.1 wt. % were saturated fatty acids, with the PS ratio 1.88, n-6/n-3 ratio 1.74, 0.80 wt. % of trans and 3.28 wt. % of very long chain n-3 fatty acids. On average, 100 g of trout meat contained 76.1 g of moisture, 21.4 g of proteins, 1.34 g of ash, 2.52 g of fat, and in the fatty acid composition 42.1 wt. % were monounsaturated, 38.2 wt. % were polyunsaturated and 18.9 wt. % were saturated fatty acids, with the PS ratio 2.02, n-6/n-3 ratio 0.98, 0.95 wt. % of trans and 13.25 wt. % of very long chain n-3 fatty acids.

New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids

International Nuclear Information System (INIS)

Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

1981-01-01

Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl 2 method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of TC-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m benzenesulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals

The Melting Behavior and Thermal Stability of Green Poly(L-lactic acid) with N, N, N, N'-Tetra(benzoyl) Ethylene Diamine Tetraacetic Acid Dihydrazide

International Nuclear Information System (INIS)

Cai, Y.; Qiang Xu, Q.; Ren, L.; Zhao, L.

2015-01-01

The thermal properties of green poly(L-lactic acid) (PLLA) with N, N, N, N'-tetra(benzoyl) ethylene diamine tetraacetic acid dihydrazide (NA) at different conditions were investigated. The melting behavior of PLLA/NA sample after isothermal crystallization at 100 degree C showed that the low-temperature melting peak shifted to high temperature with increasing of crystallization time. However, the high-temperature melting peak did not show any change. Meantime, the melting enthalpy of cold crystallization was higher than that of hot crystallization, and the difference between cold crystallization and hot crystallization increased from 0.31 J/g to 0.89 J/g with increasing of crystallization time. Heating or cooling rate affected the melting behavior of PLLA, the low-temperature and high-temperature melting peak shifted to low temperature with increasing of rate, and the ratio of melting peak area between low-temperature melting peak and high-temperature melting peak decreased. Thermal stability of PLLA/NA indicated that PLLA/NA only exhibited one decomposition stage as decomposition of PLLA. (author)

Microwave-Enhanced Cross-Coupling Reactions Involving Alkynyltrifluoroborates with Aryl Bromides

Directory of Open Access Journals (Sweden)

George W. Kabalka

2013-01-01

Full Text Available Palladium-catalyzed alkynylation has emerged as one of the most reliable methods for the synthesis of alkynes which are often used in natural product syntheses and material science. An efficient method for coupling alkynyltrifluoroborates with various aryl bromides in the presence of a palladium catalyst has been developed using microwave irradiation. The microwave reactions are rapid and efficient.

AMINOMETHANESULPHONIC ACIDS AND ITS N-DERIVATIVES ARE COMPONENTS OF N. GOODS BUFFERS

Directory of Open Access Journals (Sweden)

R.E. Khoma

2015-11-01

Full Text Available On the basis of pH measuring the temperature dependence of the second ionization constant (pK2 are set for aminomethansulfonic acid (AMSA and its N-derivatives. It was found that the area of  effective buffering of AMSK and its N-benzyl derivative allows to maintain the pH of acid-compatible with life. The absolute values  of the coefficients in the equation pK2 = -Ai+ Bi/T for the aminosulfonic acids correlated with their molar masses. A simultaneous change in values  DpH /DT and Bicoefficient for the studied acids QSAR method are stayed. The values  of the distribution coefficients in the octanol – water (Pow and molar refraction are calculated. In the future the data obtained in this study will be used to predict the physical, chemical and toxicological properties of the compounds studied.

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

DEFF Research Database (Denmark)

Santilli, Carola; Madsen, Robert

the carboxylate.  Manganese catalyzed radical Kumada-type reaction between aryl halidesand aryl Grignard reagents. The reaction between aryl halides and aryl Grignard reagents catalyzed by MnCl2 has been extended to several methyl-substituted aryl iodide reagents byperforming the reaction at 120 ˚C in a microwave...... oven (Scheme ii). A limitation of the heterocoupling process is the concomitant dehalogenation of the aryl halide and homocoupling of the Grignard reagent leading low to moderate yields of the desired heterocoupling product. The mechanism of the cross-coupling process was investigated by performing two...

Microbial CH4 and N2O consumption in acidic wetlands

Directory of Open Access Journals (Sweden)

Steffen eKolb

2012-03-01

Full Text Available Acidic wetlands are global sources of the atmospheric greenhouse gases methane (CH4, and nitrous oxide (N2O. Consumption of both atmospheric gases has been observed in various acidic wetlands, but information on the microbial mechanisms underlying these phenomena is scarce. A substantial amount of CH4 is consumed in sub soil by aerobic methanotrophs at anoxic–oxic interfaces (e.g., tissues of Sphagnum mosses, rhizosphere of vascular plant roots. Methylocystis-related species are likely candidates that are involved in the consumption of atmospheric CH4 in acidic wetlands. Oxygen availability regulates the activity of methanotrophs of acidic wetlands. Other parameters impacting on the methanotroph-mediated CH4 consumption have not been systematically evaluated. N2O is produced and consumed by microbial denitrification, thus rendering acidic wetlands as temporary sources or sinks for N2O. Denitrifier communities in such ecosystems are diverse, and largely uncultured and/or new, and environmental factors that control their consumption activity are unresolved. Analyses of the composition of N2O reductase genes in acidic wetlands suggest that acid-tolerant Proteobacteria have the potential to mediate N2O consumption in such soils. Thus, the fragmented current state of knowledge raises open questions concerning methanotrophs and dentrifiers that consume atmospheric CH4 and N2O in acidic wetlands.