The Structure of Viscosin, A Peptide Antibiotic: I: Syntheses of D- and L-3-Hydroxyacyl-L-leucine Hydrazides Related to Viscosin

Abstract

Sixteen D-and L-3-hydroxyacyl-L-leucine hydrazides related to viscosin have been synthesized. Condensation of dl-3-hydroxy fatty acids with L-leucine methyl ester by the azide method or the active ester method gave DL-3-hydroxyacyl-L-leucine methyl esters, which were then converted to their hydrazides. Each of the racemic hydrazides could readily be resolved into the respective optically active diastereoisomers by means of fractional crystallization using alcohols. All of the d-and L-3-hydroxyacyl-L-leucine hydrazides prepared showed antimicrobial activity against four kinds of microorganisms only comparable to or less than that of the saturated straight chain fatty acids of corresponding carbon numbers. © 1971, The Pharmaceutical Society of Japan. All rights reserved.