A direct strategy to obtain N-acyl amino acid oxime esters has been developed through the dynamic kinetic resolution of azlactones with oximes. In the presence of a chiral bisguanidinium salt catalyst, a variety of chiral N-acyl amino acid oxime esters were generated in excellent enantiomeric excesses (up to 97%) and high yields (up to 99%). The active oxime esters could be used in dipeptide sy...

Methyl esters of polyunsaturated fatty acids labeled with tritium were prepared by partial stereoselective reduction of the corresponding acetylenic esters with tritiated disiamylborane, followed by protonolysis with tritiated acetic acid. The labeling was strictly specific, and the tritium atoms were located only at the carbon atoms forming the unsaturated bond(s). Synthesis of some tritiated ...

The present communication deals with the local anesthetic activity and toxicity of 16 basic alkyl esters of substituted pyrrolidine dicarboxylic acids.t In an accompanying article5 the intestinal, uterine, and depressor activity of these compounds is presented. Twelve of the compounds were 2, 5-di-(3-diethylaminoethyl) esters and 3 were 2, 5-di-(y-diethylaminopropyl) esters. One was 2-(Zdiethyl...

this study presents the influence of hydroxypropyl-β-cyclodextrin (hpbcd) on the aqueous solubility of acyl esters of cyproterone. first, a number of esters of cyproterone were synthesized. then the phase solubility analysis of the compounds in the presence of hpbcd was investigated in phosphate buffer solution at a ph of 7.4. to gain a better understanding of the complexation mechanism, the sy...

ethoxylated fatty acids or polyoxyethylene esters of fatty acids possess surface active characteristic depending on ethoxylation degree (glycol type used).they have a wide range of applications and are known by formulated trade names.fatty acids used as starting materials are obtained by the hydrolysis of fats and oils and thus the final products are fully biodegradable.the objective of this in...

Reaction of dialkyl acetylenedicarboxylates 1a-c andpyrrole derivatives 2a-e in the presence of triphenylphosphite (TPP) was investigated and the effect of the pyrrole substitution was established. Diastereoselectivity is observed with pyrroles, 2a,b, yieldingphosphonate ester derivatives 3a-f and 4,and their relative configuration is determined by 1H/13C and 31</...

Barium salts of dibenzylidene cystines 8a-c were obtained from the reaction of Lcystine with benzaldehyde or its derivatives in the presence of barium hydroxide. Their reduction with zinc and hydrochloric acid in methanol yielded the Narylmethylcysteines ?9a-c?. These can, in turn, be converted by esterification into the methyl esters ?10 a-c. ?Reaction of N, N'-carbonyl diimidazole (Im C...

Retinol and retinyl esters are measured in serum or plasma samples by gradient, normal-phase, adsorption "high-performance" liquid chromatography, with ultraviolet detection at 325 nm. The four major circulating retinyl esters in humans (esters of palmitate, stearate, oleate, and linoleate) are coeluted as a single peak. Retinyl acetate is included as an internal standard, to correct for variab...

Interferons (IFNs) induce the expression of a variety of cellular RNAs. Phorbol esters can inhibit IFN-induced expression of some of these RNAs, including ISG-54K. The actions of phorbol esters on IFN-activated ISG-54K transcription are cell specific and are reversed by inhibitors of protein synthesis. In those cell lines in which phorbol esters inhibit IFN-induced ISG-54K transcription, prolon...

The cuticular surface lipids of the red harvester ant, Pogonomyrmex barbatus, were found to contain minor amounts of novel wax esters, in addition to the major components, hydrocarbons. The wax esters ranged in carbon number from C19 to C31 and consisted of esters of both odd- and even-numbered alcohols and acids. Each wax ester with a given carbon number eluted at several different retention t...