Phenyl-thio-carbonyl Chloride as a Group-protecting Agent

Abstract

THE use of the carbobenzoxy reagent for protection of amino-groups in the course of peptide synthesis has, in spite of its obvious advantages, some limitations. In some cases, hydrogenolysis of the benzyl group is complicated by simultaneous hydrogenation of other groups present, and also carbobenzoxy compounds are sometimes difficult to crystallize ; for example, N-carbobenzoxy-glycyl-cysteine ethyl ester. The use of another protecting unit easily removed by hydrolysis in combination with the carbobenzoxy method would considerably extend the use of the latter.