A FACILE SYNTHETIC APPROACH TO THE FRAGMENT D OF ANTIBIOTIC NOSIHEPTIDE, 2-[1-AMINO-3-CARBOXY-3-HYDROXY-(1<i>S</i>,3<i>S</i>)-PROPYL]-THIAZOLE-4-CARBOXYLIC ACID
The lactam corresponding to fragment D of a polypeptide antibiotic nosiheptide was prepared via oxidation of the corresponding thiazolidine-4-carboxylate obtained by the condensation of 2-azido-2,3-dideoxy-d-threo-pentoalduronate with l-cysteine methyl ester.
The reduction of aromatic ketones by borane in the presence of the inseparable diastereoisomeric mixture of 2-substituted thiazolidine-4-methanol has been investigated. Modest to high enantiomeric excesses were obtained increasing with thiazolidine steric hindrance. (C) 1997 Elsevier Science Ltd.