Phenylhydrazide as a Protective Group in Peptide Synthesis. The Oxidation of γ-Phenylhydrazides of N-Carbobenzoxy-α-L-glutamylamino Acid Esters with Manganese Dioxide
Phenylhydrazide as a Protective Group in Peptide Synthesis. The Oxidation of γ-Phenylhydrazides of N-Carbobenzoxy-α-L-glutamylamino Acid Esters with Manganese Dioxide
Carboxylates react rapidly and smoothly with 3-unsubstitutedisoxazoliumsalts under very mild conditions to yield enol esters. In this paper we report the application of this reaction as the carboxyl-activating step in a simple and practical synthesis of peptides. The utility of the specific peptide forming reagent, N-ethyl-5-phenylisoxazolium-3′-sulfonate, is described in some detail.