Preparation of anionic active ester derivatives of amino acids

Abstract

Benzyloxycarbonyl amino acids were condensed with the 2,4,6-trimethylbenzyl esters of 4-hydroxy-3-nitro-benzoic and-phenylacetic acids to give crystalline protected active esters, which could then beconverted into anionic derivatives by either selective or complete removal of the protecting groups.Several anionic active esters of aliphatic dicarboxylic acids were also prepared similarly.