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Salimon Jumat - - 2011
For environmental reasons, a new class of environmentally acceptable and renewable biolubricant based on vegetable oils is available. In this study, oxirane ring opening reaction of monoepoxide linoleic acid (MEOA) was done by nucleophilic addition of oleic acid (OA) with using p-toluene sulfonic acid (PTSA) as a catalyst for synthesis ...
Gregory Melissa K - - 2011
Δ6-Desaturase (Fads2) is widely regarded as rate-limiting in the conversion of dietary α-linolenic acid (18:3n-3; ALA) to the long-chain omega-3 polyunsaturated fatty acid docosahexaenoic acid (22:6n-3; DHA). However, increasing dietary ALA or the direct Fads2 product, stearidonic acid (18:4n-3; SDA), increases tissue levels of eicosapentaenoic acid (20:5n-3; EPA) and docosapentaenoic ...
Fink Patrick - - 2011
Recent studies have indicated that nitrogen availability can be an important determinant of primary production in freshwater lakes and that herbivore growth can be limited by low dietary nitrogen availability. Furthermore, a lack of specific essential nitrogenous biochemicals (such as essential amino acids) might be another important constraint on the ...
Jawara Musa - - 2011
Odour baited traps have potential use in population surveillance of insect vectors of disease, and in some cases for vector population reduction. Established attractants for human host-seeking mosquitoes include a combination of CO(2) with L-lactic acid and ammonia, on top of which additional candidate compounds are being tested. In this ...
Zhang Yingwei - - 2011
In this paper, we demonstrate for the first time that poly(m-phenylenediamine) (PMPD) nanospheres and nanorods can be selectively synthesized via chemical oxidation polymerization of m-phenylenediamine (MPD) monomers using ammonium persulfate (APS) as an oxidant at room temperature. It suggests that the pH value plays a critical role in controlling the ...
Jing Fuyuan - - 2011
Acyl-acyl carrier protein thioesterases (acyl-ACP TEs) catalyze the hydrolysis of the thioester bond that links the acyl chain to the sulfhydryl group of the phosphopantetheine prosthetic group of ACP. This reaction terminates acyl chain elongation of fatty acid biosynthesis, and in plant seeds it is the biochemical determinant of the ...
Elemo Babajide O BO Biochemistry Department, Lagos State University, Lagos, Nigeria. - - 2011
The chemical properties of the African palm weevil, Rhychophorus phoenicis (F.) (Coleoptera: Curculionidae), larvae were evaluated using standard methodology. The chloroform-methanol extract yielded 37.12% on a dry basis. The oil was liquid at room temperature with a flash point of 36.0 °C. Analysis of the physical constants indicated values of ...
Shen Qian Jin - - 2011
The free 3-quinolineboronic acid (3-QBA) with the lowest (n-π*) excited singlet is non- or weakly fluorescent while protonated 3-QBA has the lowest (π-π*) excited singlet state and is highly fluorescent. The hybridization of boronic atom or charge transfer from aromatic ring to boronic acid group plays a secondary role in ...
Scott Spencer D - - 2011
Glucose is the typical carbon source for producing microbial polyunsaturated fatty acids (PUFA) with single cell microorganisms such as thraustochytrids. We assessed the use of a fish oil derived glycerol by-product (raw glycerol), produced by a fish oil processing plant, as a carbon source to produce single cell oil rich ...
Kalaitzakis E - - 2010
To evaluate the macromineral status of field cases of dairy cows surgically treated for left abomasal displacement (LDA), with concurrent fatty liver of different severity, and compare this for animals that died or recovered. Sixty-eight Holstein dairy cows with LDA and 110 control cows, from 28 farms, were used in ...
Vilà Laia - - 2011
Consumption of beverages that contain fructose favors the increasing prevalence of metabolic syndrome alterations in humans, including non-alcoholic fatty liver disease (NAFLD). Although the only effective treatment for NAFLD is caloric restriction and weight loss, existing data show that atorvastatin, a hydroxymethyl-glutaryl-CoA reductase inhibitor, can be used safely in patients ...
Viedma Cristóbal - - 2011
A straightforward unprecedented sublimation protocol that reveals both conversion of a racemic compound into a racemic conglomerate and subsequent enantioenrichment has been developed for the proteinogenic amino acid valine. The phenomenon has been observed in closed and open systems, providing insight into asymmetric amplification mechanisms under presumably prebiotic conditions.
Palkovits Regina - - 2011
Cellulose and even spruce can be converted efficiently into valuable platform chemicals via combined hydrolysis and hydrogenation in the aqueous phase. Thereby, heteropoly acids together with supported ruthenium catalysts show not only high activity but also remarkable selectivity to sugar alcohols reaching up to 81% yield of C(4) to C(6) ...
Benoit Maud - - 2010
Ionic liquids (ILs) can be partially substituted by glycerol or glycerol carbonate as cheap, safe, and renewably sourced co-solvents in the acid-catalyzed dehydration of fructose and inulin to 5-hydroxymethylfurfural (HMF). In the particular case of glycerol, we found that HMF can be conveniently extracted from the IL/glycerol (65:35) mixture with ...
Vermoortele Frederik - - 2011
After controlled pretreatment, some Zr-terephthalate metal-organic frameworks are highly selective catalysts for the cross-aldol condensation between benzaldehyde and heptanal. The proximity of Lewis acid and base sites in the amino-functionalized UiO-66(NH(2)) material further raises the reaction yields.
Amgoune Abderrahmane - - 2011
The ability of Lewis acids to coordinate to transition metals as σ-acceptor ligands was recognized as early as in the 1970's, but so-called Z-type ligands remained curiosities until the early 2000's. Over the last decade, significant progress has been made in this area, especially via the incorporation of Lewis acid ...
Grach Guillaume - - 2011
New Yb(OTf)(3)-pyridylalkylamine complexes have been employed as chiral Lewis acids in the enantioselective Friedel-Crafts alkylation of indole derivatives with trifluoropyruvates. The influence of the substituents as well as the configuration of the ligands have been studied and allowed us to reach enantiomeric excesses up to 83%.
Fang Yuan-Qing - - 2010
A general inversion-stereospecific, N-selective alkylation of substituted 2-pyridones (and analogues), amides, and carbamates using chiral α-chloro- or bromocarboxylic acids in the presence of KOt-Bu (or KHMDS) and Mg(Ot-Bu)(2) is reported. The resulting α-chiral carboxylic acid products were isolated by crystallization in good chemical yields and in high ee (>90% ee). ...
Seki Hajime - - 2010
Cyclic enaminones were synthesized in high yields from amino acids in two steps via Wolff rearrangement. The cyclization represents a rare 6-exo-dig cyclization involving a ketene as an electrophile. No racemization was observed during this reaction.
Napolitano Carmela - - 2010
An approach to resorcylic acid lactones is described, exploiting an intramolecular olefination reaction for the generation of the 14-membered macrolactone. The synthetic route gave zearalenone precursors, and the preparations of other RAL analogues, trans- and cis-resorcylides are included, the latter being prepared by photoisomerization of the trans-isomer. β-Haloketone derivatives were ...
Holloway Chloe A - - 2010
A direct enantio- and diastereoselective N-acyliminium cyclization cascade through chiral phosphoric acid catalyzed condensation of tryptamines with γ- and δ-ketoacid derivatives to provide architecturally complex heterocycles has been developed. The reaction is technically simple to perform, atom-efficient, and broad in scope. Employing 10 mol % of (R)-BINOL derived chiral phosphoric ...
Zhang Fengzhi - - 2010
Decarboxylative cross-coupling of thiazole and oxazole-5-carboxylic acids with aryl halides is reported. Under a bimetallic system of catalytic palladium and a stoichiometric silver carbonate, a variety of (hetero)arylated azoles can be prepared in excellent yield.
Jensen Katrina H - - 2010
A modular catalyst structure was applied to evaluate the effects of catalyst acidity in a hydrogen bond-catalyzed hetero Diels-Alder reaction. Linear free energy relationships between catalyst acidity and both rate and enantioselectivity were observed, where greater catalyst acidity leads to increased activity and enantioselectivity. A relationship between reactant electronic nature ...
Reilly Maureen K MK Department of Chemistry, 1102 Natural Sciences II, University of California-Irvine, Irvine, California 92697, United - - 2010
Alkyl dioxazaborolidines are air-stable and often crystalline organoboranes. A variety of Brønsted acids activate allyl dioxazaborolidines to generate reactive allyl-transfer reagents in situ. These reagents add to aldehydes and ketones to generate the corresponding alcohols in good yields under mild conditions. The E- and Z-crotyl reagents react diastereoselectively with aldehydes ...
Dubey Rama - - 2010
Optically active polyaniline (PANI) salts were readily generated in solution via the enantioselective acid doping of neutral emeraldine base (EB) form of PANI with either (+) or (-)-2-pyrrolidone-5-carboxylic acid (PCA) in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solvents. Strong mirror imaged circular dichroism (CD) spectra were obtained for the deep green ...
Kim Manhoe - - 2011
In order to achieve a viable biodiesel industry, new catalyst technology is needed which can process a variety of less expensive waste oils, such as yellow grease and brown grease. However, for these catalysts to be effective for biodiesel production using these feedstocks, they must be able to tolerate higher ...
Chen Guo - - 2011
The aim of this work is to study the catalyst prepared by glucose-starch mixture. Assessment experiments showed that solid acid behaved the highest esterification activity when glucose and corn powder were mixed at ratio of 1:1, carbonized at 400°C for 75 min and sulfonated with concentrated H(2)SO(4) (98%) at 150°C ...
Brazeau Allison L - - 2010
A bis(imino)acenaphthene (BIAN) ligand containing a pendant Lewis base has been used as a new framework to support a N-heterocyclic phosphenium cation (NHP). Reactivity studies demonstrate the ability of the ligand to act as a Lewis base, while the phosphorus centre provides a Lewis acidic site, giving new opportunities in ...
Pattison Graham - - 2010
In the presence of a rhodium complex containing a newly developed chiral diene ligand, alkenes activated by a range of π-deficient or π-excessive heteroarenes engage in highly enantioselective conjugate additions with various arylboronic acids.
Ohmura Satoshi D SD Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871, - - 2010
Aniline oligomers bearing amino acid moieties were designed by the introduction of l/d-Ala-OMe into aniline oligomers to induce chirality organization of the π-conjugated aniline oligomer moieties, wherein the formation of intramolecular hydrogen bonds was demonstrated to play an important role to regulate the aniline oligomer moieties conformationally.
Roth Christian - - 2010
During two-dimensional chiral conglomerate formation of tartaric acid on the copper(110) surface, the growth of one enantiomorph is suppressed by the opposite chirality of a coadsorbed malic acid enantiomer, forming a quasi-racemic, semi-ordered mixture.
Cant Alastair A - - 2010
ortho C-H activation of benzoic acids with Pd(II) generates an oxapalladacycle that can decarboxylate to produce a palladium-associated aryne. The arynes then undergo [2+2+2] trimerisation to afford triphenylenes.
Nguyen Thanh Binh - - 2010
The first enantioselective chiral phosphoric acid-catalyzed transfer hydrogenation of unprotected ortho-hydroxyaryl alkyl N-H ketimines using Hantszch di-tert-butyl ester as a reductant is reported. A variety of ortho-hydroxybenzylamines were obtained in good to excellent yields and enantiomeric excesses.
Furuta Takumi - - 2010
Novel optically active axially chiral amino acid and amino alcohols have been synthesized efficiently via lactam ring-opening, with the aid of an optically active alcohol, amidoaza[5]helicene 5, which has been readily prepared by an additive-ligand-free Pd catalyzed domino coupling reaction in a single step. The stereostructures of these chiral molecules ...
Songis Olivier - - 2010
A general synthetic methodology for the preparation of functionalized (hetero)helicenes has been developed. It employs the sequence of a double propargyl organometallics (Li, Mg, Ga/In) addition to a tolan-2,2'-dialdehyde-type intermediate, a cobalt-catalyzed/cobalt-mediated [2 + 2 + 2] cycloisomerization of a triyne intermediate, and a double silica gel-assisted acetic acid elimination ...
Kinzel Tom T Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United - - 2010
Boronic acids which quickly deboronate under basic conditions, such as polyfluorophenylboronic acid and five-membered 2-heteroaromatic boronic acids, are especially challenging coupling partners for Suzuki-Miyaura reactions. Nevertheless, being able to use these substrates is highly desirable for a number of applications. Having found that monodentate biarylphosphine ligands can promote these coupling ...
Chen Hongzhang - - 2011
In this study, solid superacid was employed to catalyze the decomposition of steam exploded rice straw (SERS) for the production of levulinic acid, a versatile platform chemical. The results revealed that solid superacid, S(2)O(8)(2-)/ZrO(2)-SiO(2)-Sm(2)O(3), could be used as a substitute for homogenous acid to catalyze the production of LA from ...
Nakao Yoshiaki - - 2010
Direct C-4-selective addition of pyridine across alkenes and alkynes is achieved for the first time by nickel/Lewis acid cooperative catalysis with an N-heterocyclic carbene ligand. A variety of substituents on both alkenes and pyridine are tolerated to give linear 4-alkylpyridines in modest to good yields. The addition across styrene, on ...
Calmes Monique - - 2011
The chiral β-nitroacrylate 2 derived from the (R)- or (S)-4-(3-hydroxy-4,4-dimethyl-2-oxopyrrolidin-1-yl) benzoic acid 1 acts as a reactive dienophile in a diastereoselective Diels-Alder reaction with 1,3-cyclohexadiene. The major cycloadducts have been isolated and transformed into enantiopure trans(2S,3S)- or (2R,3R)-N-Boc-3-aminobicyclic[2,2,2]octane-2-carboxylic acids 5. The trans-(2S,3S)- or (2R,3R)-N-Boc 3-(hydoxymethyl)-2-aminobicyclic[2,2,2]octane 6 derivatives were also obtained. ...
Huang Yan-Jun - - 2010
The exciplex formation between a pyridinium boronic acid and phenyl group connected via a propylene linker can be monitored using fluorescence. Addition of pinacol affords a cyclic boronate ester with enhanced Lewis acidity that increases the strength of its cation-π stacking interaction causing a four-fold fluorescence enhancement.
Morán-Ramallal Roberto - - 2010
Several racemic trans-3-arylaziridine-2-carboxamides were prepared and then resolved by Rhodococcus rhodochrous IFO 15564-catalyzed hydrolysis. The resulting enantiopure (2R,3S)-3-arylaziridine-2-carboxamides are adequate substrates to undergo fully stereoselective nucleophilic ring-openings at the C-3 ring position to finally yield enantiopure, unnatural d-α-aminocarboxylic acids. Experimental evidence is provided that suggests the fate of the (2S,3R)-3-arylaziridine-2-carboxylic ...
Ghosn Marwan W - - 2010
Suzuki cross-coupling of a 1,8-dihalonaphthalene with 4-methoxy-3-methylphenylboronic acid or 4-acetamidophenylboronic acid and subsequent functional group transformation gave 1,8-bis(3'-methyl-4'-anilino)naphthalene, 16, and 1,8-bis(4'-anilino)naphthalene, 21, in 65% and 90% overall yield, respectively. These congested compounds exhibit two cofacial aniline rings that favor a proximate, parallel arrangement of covalently attached cinnamoyl units suitable for ...
Susperregui Nicolas - - 2010
The mechanism of ring-opening of ε-caprolactone by methanol catalyzed by trifluoromethane and methane sulfonic acids has been studied computationally at the DFT level of theory. For both elementary steps, the sulfonic acid was predicted to behave as a bifunctional catalyst. The nucleophilic addition proceeds via activation of both the monomer ...
Yamano Yumiko - - 2010
The synthesis of 3'-deoxycapsanthin (1) and 3,4-didehydroxy-3'-deoxycapsanthin (2), carotenoids of paprika, has been achieved by employing Lewis acid-promoted regio- and stereoselective rearrangement of the C(15)-epoxy dienal 5a. The absolute stereochemistry of the newly formed C-5 chiral center of rearrangement product 6a was determined to be (R) from its alternative synthesis ...
Maruoka Keiji - - 2010
A series of chiral quaternary ammonium salts derived from commercially available (R)- or (S)-binaphthol have been designed as new C(2)-symmetric chiral phase transfer catalysts. In order to realize the flexible design of these phase transfer catalysts, the combinatorial design approach has been developed. These chiral high-performance organocatalysts have been successfully ...
Chuang Ta-Hsien - - 2010
A series of disubstituted pyridine derivatives was synthesized from the corresponding acryloyl azides by acetic acid-promoted cycloaddition. This represents a novel and convenient synthetic approach to the symmetric 3,5-disubstituted pyridines. The nature of the substituent on the double bond and the utilized solvent were found to be crucial to the ...
Orthaber Andreas - - 2010
The synthesis, structure and reactivity of the fluoroaryl phosphinic acid HF(4)C(6)-P(O)HOH is reported and compared to a sterically comparable yet non-fluorinated analog with similar size. The fluoroaryl phosphinic acid undergoes reversible P-H addition to the carbonyl functionality of ketones under formation of a P-C bond which is retained in the ...
Seiple Ian B IB Department of Chemistry and Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, - - 2010
A direct arylation of a variety of electron-deficient heterocycles with arylboronic acids has been developed. This new reaction proceeds readily at room temperature using inexpensive reagents: catalytic silver(I) nitrate in the presence of persulfate co-oxidant. The scope with respect to heterocycle and boronic acid coupling partner is broad, and sensitive ...
Mughal Ehsan U - - 2010
A series of tribenzotriquinacene derivatives bearing three oxy-functionalised alkyl groups at the benzhydrylic bridgeheads (C-4b, C-8b and C-12b) have been synthesised. The 4b,8b,12b-triallyl derivative was used to generate the corresponding TBTQ-tris-acetaldehyde and TBTQ-tris(acetic acid), in which the functional groups stretch out from the convex rigid molecular surface. The corresponding tribromo ...
Berkecz Róbert - - 2010
Chiral discrimination of seven enantiomeric pairs of β-3-homo-amino acids was studied by using the kinetic method and trimeric metal-bound complexes, with natural and unnatural α-amino acids as chiral reference compounds and divalent metal ions (Cu(2+) and Ni(2+) ) as the center ions. The β-3-homo-amino acids were selected for this study ...
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