Search Results
Results 51 - 100 of 1887
1 2 3 4 5 6 7 8 9 10 >
Sutton Paul A - - 2010
Polycyclic C(80) tetracarboxylic (so-called 'ARN') acids are found as calcium salts in deposits which form in certain oilfield pipelines and equipment. Characterisation of these acids is important for improving the prediction and hence avoidance or minimisation of oilfield deposition problems. Although several of the acids have been isolated and characterised ...
Zanoni Giuseppe - - 2010
Endogenous nitro-fatty acids, acting as partial agonist of PPARγ, are able to lower the insulin and glucose levels without the side effects associated with common antidiabetic drugs. (E)-12-Nitrooctadec-12-enoic acid, a potent activator of this peroxisome receptor, was synthesized in a very efficient sequence via a Henry-retro-Claisen ring fragmentation, followed by ...
Arnosti André - - 2011
This study examines the effects of ricinoleic acid esters from Ricinus communis castor oil on the vitellogenesis of Rhipicephalus sanguineus ticks attached to hosts that were fed with commercial rabbit food containing these esters. The oocytes of ticks from the treatment group (TG) showed cytoplasmic changes that inhibited the development ...
Duggan Peter J - - 2010
The scope of a tandem conjugate addition-fluorination sequence performed on α,β-unsaturated esters using the enantiopure lithium amide derived from (S)-N-benzyl-N-(α-methylbenzyl)amine, and the electrophilic fluorinating agent N-fluorobenzenesulfonimide has been investigated. Using this method, α-fluoro-β(3)-amino esters can be obtained in up to quantitative yield and 80:20 to >99:1 dr. This simple methodology ...
Wang Ergang - - 2010
The nitration of 4,7-dibromo-2,1,3-benzothiadiazole was modified by using CF(3)SO(3)H and HNO(3) as the nitrating agent, and the related yield was improved greatly. On the basis of this improvement, two new small band gap polymers, P1TPQ and P3TPQ, were developed. Bulk heterojunction solar cells based on P3TPQ and [6,6]-phenyl-C(71)-butyric acid methyl ...
Gaspar Alexandra A CIQ/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, - - 2010
The action of sinapic acid and its alkyl esters as potential antioxidants has been investigated. For this purpose, a series of sinapic acid ester derivatives was synthesized and their antioxidant activities were evaluated using distinctive analytical methods, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and FRAP UV-vis methods and differential scanning calorimetry. The electron-donating ...
Jursic Branko S - - 2010
Synthetic modifications of cholesterol and other traditional steroid molecules have become a promising area for the exploration and development of novel antifungal agents, especially with respect to the development of fatty-acid esters of steroids. In addition, 2,3-functionalized steroids are also compounds with potentially interesting biological properties and proper functionalization of ...
Ono Masateru - - 2010
Treatment of the crude ether-insoluble resin glycoside (convolvulin) from seeds of Pharbitis nil (Pharbitis Semen), called pharbitin, with indium(III) chloride in methanol provided seven oligoglycosides of hydroxy fatty acid methyl esters partially acylated by 2-methyl-3-hydroxybutyric (nilic) and 2S-methylbutyric acids. Their structures were elucidated on the basis of NMR and MS ...
Jermsuntiea Worapol - - 2011
Previous studies on an arachidonic acid-producing fungus, Mortierella alliacea YN-15, suggested that its intracellular lipase plays an important role in the metabolism of exogenous and storage lipids. The lipase purified in this study through acetone precipitation and three-step chromatography was estimated to be about 11kDa in size by SDS-PAGE and ...
Juhl P B - - 2010
Candida antarctica lipase B (CALB) is a widely used biocatalyst with high activity and specificity for a wide range of primary and secondary alcohols. However, the range of converted carboxylic acids is more narrow and mainly limited to unbranched fatty acids. To further broaden the biotechnological applications of CALB it ...
Babu P David Suresh - - 2011
The FT-Raman and FT-IR spectra for benzenesulfonic acid methyl ester (BSAME) have been recorded in the region 4000-100 cm(-1) and compared with the harmonic vibrational frequencies calculated using DFT (LSDA, B3LYP, B3PW91 and MPW1PW91) method by employing 6-311G (d, p) basis set with appropriate scale factors. IR intensities and Raman ...
Solé Daniel - - 2010
Two efficient palladium-catalyzed intramolecular α-arylation reactions of α-amino acid esters have been developed that allow either 1-isoindolecarboxylic acid esters or the corresponding isoindolines to be selectively synthesized simply by a slight change of reaction conditions.
Wilkening Ina - - 2011
The Staudinger reaction of unprotected azido-peptides with silylated phosphinic acids and esters on the solid support offers a straightforward acid-free entry to different phosphonamidate peptide esters or acids under mild conditions in high purity and yield.
Acosta Andreina - - 2011
Partial acylation of only one primary hydroxyl group of glycerol generates a chiral center at position 2. Rhizomucor miehei lipase (RML) catalyzes the kinetically controlled transesterification of different aromatic carboxylic acids methyl esters with glycerol. High synthetic yields of glyceryl esters (around 70-80%) were obtained even in the presence of ...
Morales-Serna José Antonio - - 2010
A facile and mild macrolactonization reaction of ω-hydroxy acids was developed based on the transesterification of benzotriazole esters. Treatment of ω-hydroxy acids with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and 1-hydroxy benzotriazole (HOBT) in chloroform provided macrolactones in excellent yields. The reactions were performed under basic, neutral and acidic conditions using N,N-dimethylaminopyridine (DMAP), ...
Abdul Rahman Mohd Basyaruddin - - 2011
Esterification of succinic acid with oleyl alcohol catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was investigated in this study. Response surface methodology (RSM) based on a five-level, four-variable central composite design (CCD) was used to model and analyze the reaction. A total of 21 experiments representing different combinations ...
Nakamura Yasushi - - 2010
Six fragrant ingredients were identified in fully-ripened Katsura-uri (Japanese pickling melon; Cucumis melo var. conomon). Four of them were sulfur-containing compounds [methylthioacetic acid ethyl ester (MTAE), acetic acid 2-methylthio ethyl ester (AMTE), 3-methylthiopropionic acid ethyl ester (MTPE), and acetic acid 3-methylthio propyl ester (AMTP)]; and the others were benzyl acetate ...
Kiss Anton Alexandru - - 2011
Reactive separations using green catalysts offer great opportunities for manufacturing fatty esters, involved in specialty chemicals and biodiesel production. Integrating reaction and separation into one unit provides key benefits such as: simplified operation, no waste, reduced capital investment and low operating costs. This work presents a novel heat-integrated reactive absorption ...
Koseki Takuya - - 2010
In this study we report the biochemical characterization of a hypothetical protein from Aspergillus oryzae exhibiting sequence identity with feruloyl esterase and tannase from the genus Aspergillus. The purified recombinant protein showed a hydrolytic activity toward the ethyl, propyl, or butyl esters of 4-hydroxybenzoic acid, but did not show feruloyl ...
Lin Steven - - 2010
Although biotin is an essential enzyme cofactor found in all three domains of life, our knowledge of its biosynthesis remains fragmentary. Most of the carbon atoms of biotin are derived from pimelic acid, a seven-carbon dicarboxylic acid, but the mechanism whereby this intermediate is assembled remains unknown. Genetic analysis in ...
Mooney Aine - - 2010
A series of N-(ferrocenyl)naphthoyl amino acid esters 5-18 has been prepared by coupling ferrocenyl naphthoic acids 3-4 to alpha-amino acids and linear amino acids in the presence of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxybenzotriazole (HOBt). The compounds were fully characterised by a range of NMR spectroscopic techniques, UV-Vis spectroscopy, mass spectrometry ...
Singh Inder Pal - - 2010
Based on reported antileishmanial activity of naturally occurring alkaloid piperine and amino acid esters, their conjugates were synthesized by the hydrolysis of piperine to piperic acid followed by reaction with amino acid methyl esters. These conjugates were further converted to compounds with free carboxyl group and those with reduced double ...
Li Yiming - - 2010
Lipopeptides and their analogues are of increasing interest due to their amphiphilic structures and potential applications in various fields. Three purified lipopeptides analogues were obtained at the same time after two-step column-chromatographic purification from cell-free broth cultivated by Bacillus licheniformis HSN 221. Analysis by ESI-MS, GC/MS, HPLC, and Q-TOF MS/MS ...
Tasior Mariusz - - 2010
The synthesis and properties of a new visible red/near-infrared fluorochrome for bioconjugation via activated ester groups is described. Representative amine conjugations with amino acid lysine and proteins lysozyme and trypsin were successfully accomplished.
Haas Michael J - - 2010
Fatty acid methyl esters (FAME) were produced from cow's milk (Bostaurus) butter by esterification/transesterification in the presence of methanol. The product was assayed according to the Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels (ASTM D 6751). The preparation failed to meet the specifications for flash ...
de Barros Dragana P C - - 2010
The aim of this work is to devise an efficient enzymatic process for the production of linear alkyl esters in aqueous miniemulsion systems. The esterification reactions of linear alcohols and carboxylic acids were performed with three different enzymes, commercial Amano lipase PS from Pseudomonas cepacia, Lipase type VII from Candida ...
Niedworok E - - 2010
The aim of the study is to analyse the changes in the profile of fatty acids and their esters in rat hepatocytes that were incubated for 5 hours with different concentrations of MgCl2 (2 and 4mM) in hepatocyte culture medium. The methyl esters of fatty acids were identified with a ...
Rostami-Yazdi Martin - - 2010
The aim of this study was to evaluate pharmacokinetic parameters of fumaric acid esters (FAE) in psoriasis patients for the first time. For this prupose new HPLC assays were developed. Additionally, physicochemical parameters of FAE were determined, allowing a better interpretation of the in vivo data. In vivo, monomethylfumarate (MMF) ...
Yang John - - 2010
A series of catechol ring-fluorinated derivatives of caffeic acid phenethyl amide (CAPA) were synthesized and screened for cytoprotective activity against H2O2 induced oxidative stress in human umbilical vein endothelial cells (HUVEC). CAPA and three fluorinated analogs were found to be significantly cytoprotective when compared to control, with no significant difference ...
Rigo Elisandra - - 2010
The main objective of this work was the isolation and screening of microorganisms with potential for producing lipases for the synthesis of fatty esters as well as evaluating the specificity of the enzymes produced, using different alcohols (methanol, ethanol, n-propanol, and butanol) and fatty acids (oleic and lauric acids) as ...
Huang Chifu B - - 2010
This study is to assess the antibacterial activity of omega-6, -7, -9 (n-6, n-7, n-9) fatty acids against various oral microorganisms. The n-6, n-7, n-9 fatty acids, such as gamma-linoleic acid (GLA), linoleic acid (LA), arachidonic acid (ARA), palmitoleic acid (PA), and oleic acid (OA), their fatty acid ethyl esters, ...
Arsianti Ade - - 2010
Novel 2-hydroxynicotinoyl-serine-butyl esters have been synthesized. Three-step reactions from L-serine by esterification with n-butanol, amidation with 2-hydroxynicotinic acid and esterification with the corresponding carboxylic acids gave AD-1, AD-2 and AD-3. The toxicity level of esters were determined by Brine shrimp assay, and antibiotic activity was tested against Escherichia coli, Bacillus ...
Gonçalves Renato S - - 2011
Potentially bioactive N-(aminoalkyl)lactamic amino acids and esters were synthesized in satisfactory to good yields by S(N)Ar reactions of aromatic acids with N-(3-aminopropyl)lactams followed by esterification with tertiary amino alcohols. The addition-elimination S(N)Ar mechanism was confirmed by NMR and MS measurements.
Kurata Atsushi - - 2010
An efficient procedure for transesterification of methyl caffeate was developed to produce caffeic acid phenethyl ester analogues with Candida antarctica lipase B using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, as a solvent. The system provided 48.8mM 2-cyclohexylethyl caffeate and 46.9 mM 3-cyclohexylpropyl caffeate with conversion yields of 97.6% and 93.8%, respectively. ...
Ito Len - - 2010
Several amino acids and their derivatives are prominent additives in the field of protein chemistry. This study reports the use of charged amino acids and glycine ethyl ester as precipitants in protein crystallization, using hen egg-white lysozyme (HEWL) as a model. A discussion of the crystallization of HEWL using these ...
Venkatesan Hariharan - - 2010
A straightforward and efficient one-step procedure for the synthesis of 2,4-unsubstituted quinoline-3-carboxylic acid ethyl esters is described. The simple reductive cyclization is carried out by treating various substituted o-nitrobenzaldehydes with inexpensive, commercially available 3,3-diethoxypropionic acid ethyl ester and SnCl(2).2H(2)O in refluxing ethanol.
Burroughs Laurence - - 2010
Esters of proteinogenic amino acids efficiently catalyse the formation of erythrose and threose under aqueous conditions in the highest yields and enantioselectivities yet reported. Remarkably while esters of (L)-proline yield (L)-carbohydrates, esters of (L)-leucine and (L)-alanine generate (D)-carbohydrates, offering the potential to account for the prebiotic link between natural (L)-amino ...
Tofani Daniela - - 2010
A large series of hydroxytyrosyl esters of C2-C18 fatty acids with increasing lipophilicity was prepared by a new highly efficient method based on acylation of methylorthoformate-protected hydroxytyrosol. All products were tested for relative antioxidant effect using ABTS assays in ethanolic medium and DCF assays in L6 cells. No linear correlation ...
Ximenes Valdecir F - - 2010
The protective effect of gallic acid and its esters, methyl, propyl, and lauryl gallate, against 2,2'-azobis(2-amidinopropane)hydrochloride (AAPH)-induced hemolysis and depletion of intracellular glutathione (GSH) in erythrocytes was studied. The inhibition of hemolysis was dose-dependent, and the esters were significantly more effective than gallic acid. Gallic acid and its esters were ...
Elbahloul Yasser - - 2010
Fatty acid ethyl esters (FAEEs) were produced in this study by the use of an engineered Escherichia coli p(Microdiesel) strain. Four fed-batch pilot scale cultivations were carried out by first using glycerol as sole carbon source for biomass production before glucose and oleic acid were added as carbon sources. Cultivations ...
Lin Iung-Jr - - 2010
The stems of Cinnamomum reticulatum Hay (Lauraceae) were extracted with hexane and chloroform successively. A series of new esters, including a mixture of 4-hydroxy-3-methoxyphenethyl derivatives, along with two butanolides, isoobtusilactone A and obtusilactone A, two amides, N-trans-feruloylmethoxytyramine and N-cis-feruloyl-methoxytyramine, three benzenoids, p-hydroxybenzoic acid, syringic acid and vanillic acid, one lignan, ...
Seenivasagan T - - 2010
Understanding on the chemical ecology of mosquito behavior is of paramount importance in developing control programs employing attractants and repellents. Several workers focused on topical repellents and oviposition attractants of mosquitoes, however, only limited work has been accomplished on mosquito oviposition repellents. The present systematic investigation provides evidence on the ...
Takashima-Hirano Misato - - 2010
Cyclooxygenase (COX) is a critical enzyme in prostaglandin biosynthesis that modulates a wide range of biological functions, such as pain, fever, and so on. To perform in vivo COX imaging by positron emission tomography (PET), we developed a method to incorporate (11)C radionuclide into various 2-arylpropionic acids that have a ...
Schmauder Anke - - 2010
The first total synthesis of the cyclodepsipeptide chondramide A (2 b) is described. This depsipeptide is composed of four subunits, namely L-alanine, N-Me-D-tryptophan, 3-amino-2-methoxy-propionic acid (beta-tyrosine derivative), and a 7-hydroxy-alkenoic acid. While the configuration of the stereogenic centers in the 7-hydroxy-alkenoic acid were known, the configuration of the tyrosine derivative ...
Brown Zachary Z - - 2010
Steric hindrance assists in the formation of hindered diketopiperazines using acyl-transfer coupling. In acyl-transfer coupling, the carboxylate of an unprotected N-alkylamino acid attacks an active ester to form a transient anhydride that undergoes an O,N acyl transfer to form a tertiary amide. If the active ester is part of an ...
Deb Somdatta - - 2010
We report the rapid synthesis (1min) in high yield of fatty acid ester (FAE) derivatives of several steroids under microwave irradiation in an ionic liquid (IL). An expedient regioselective hydrolysis at C-3 of estradiol diesters is also reported.
Novotný Michal - - 2010
Transkarbam 12, an ammonium carbamate formed by the reaction of dodecyl 6-aminohexanoate with carbon dioxide, is a highly active, broad-spectrum, nontoxic, and nonirritant transdermal permeation enhancer. It probably acts by a dual mechanism: a part of its activity is associated with the carbamic acid salt and/or its decomposition in the ...
Ichihara Ken'ichi - - 2010
KOH in aqueous methanol catalyzes selective methanolysis of polar glycerolipids with O-ester-linked acyl residues, while triacylglycerols and sterol esters are inert in the solution. Based on these findings, a convenient and reliable method was developed for the preparation of fatty acid methyl esters (FAMEs) from polar glycerolipids in lipid mixtures ...
Durcekova T - - 2010
Several chemometrical techniques were applied to elucidate anaesthetical activity of hydrochlorides of alkoxyphenylcarbamic acid esters. The studied five types of esters contained morpholin-4-ylethyl-, piperidin-1-ylethyl-, piperidin-1-ylpropyl-, azepan-1-ylethyl- and dimethylaminoethyl- groups. The surface anaesthetical activity, designated by A, and the infiltration anaesthetical activity, indicated by B, were correlated to lipophilicity, expressed in ...
Okitsu Takashi - - 2010
Palladium-catalyzed cross-coupling reactions of a 2-substituted 3-iodobenzo[b]furans and stannanyl ester afforded the stereoselective production of 9Z-retinoic acid ester analogs in good yields. These esters were then converted to the corresponding acids via basic hydrolysis in excellent yields, and their biological activities were evaluated. The analog changed the connected position of ...
1 2 3 4 5 6 7 8 9 10 >