Effect of the α-Methyl Substituent on Chemoselectivity in Esterase-Catalyzed Hydrolysis of <i>S</i>-Acetyl Sulfanylalkanoates
作者:Ish Kumar、Ravinder S. Jolly
DOI:10.1021/ol990544+
日期:1999.7.1
The isomeric compounds 1 and 3, which differ only in the position of a methyl substituent, give opposite chemoselectivities in an esterase-catalyzed hydrolysis reaction. The esterase was chemoselective for the oxoester in 1, but for the thiol ester group in 3. A high enantioselectivity was observed for both 1 and 3.
Evidence for α-lactone formation in the thioacetylation of some α-hydroxy acids with the aid of <i>Mitsunobu</i>
-type reagent
作者:Bert Strijtveen、Richard M. Kellogg
DOI:10.1002/recl.19871061006
日期:——
(S-Mandelic acid, (S)-lactic acid, and (S)-2-hydroxy-3-phenylpropionic acid react with thioacetic acid in the presence of the salt of diisopropyl azodicarboxylate and triphenylphosphine to give the α-(acetylthio)-substituted products. (S)-Mandelic acid reacts with predominant retention of configuration whereas (S)-lactic acid and (S)-2-hydroxy-3-phenylpropionic acid react predominantly with inversion
Compounds containing a fused bicycle ring and processes therefor
申请人:Bristol-Myers Squibb Company
公开号:US05508272A1
公开(公告)日:1996-04-16
Compounds of the formula ##STR1## wherein X is O or S--(O).sub.t ; n is one or two; m is zero or one; Y is CH.sub.2, O, or S--(O).sub.t provided that Y is O or S--(O).sub.t only when m is one; and A is ##STR2## are dual inhibitors of NEP and ACE. Compounds wherein A is ##STR3## are selective ACE inhibitors. Also disclosed are methods of preparation and intermediates.
A Flexible Route to (5<i>R</i>)-Thiolactomycin, a Naturally Occurring Inhibitor of Fatty Acid Synthesis
作者:Jill M. McFadden、Gojeb L. Frehywot、Craig A. Townsend
DOI:10.1021/ol026685k
日期:2002.10.1
[formula: see text] A new and efficient asymmetric synthesis of naturallyoccurring (5R)-thiolactomycin (1) using D-alanine as the source of chirality is described.
描述了一种以D-丙氨酸为手性来源的天然高效(5R)-硫代催乳素(1)的新型高效合成方法。
Process for preparing homocystein analogs useful as intermediates for
申请人:Bristol-Myers Squibb Co.
公开号:US05616775A1
公开(公告)日:1997-04-01
Homocysteine analogs of the formula ##STR1## wherein P.sub.1 is a nitrogen protecting group and R.sub.6 is alkyl, substituted alkyl or benzyl are prepared by esterifying N-protected L-methionine, oxidizing, treating the resulting sulfoxide with an acid anhydride, treating the resulting product with an alkali metal hydroxide followed by removal of formaldehyde and the treatment with an acid anhydride or acid halide. The L-homocysteine analogs are useful as intermediates in the preparation of compounds containing a fused bicyclic ring.