A synthesis of N‐phthaloyl amino acids and amino acid esters under mild conditions

Abstract

AbstractThe racemization‐free synthesis of N‐phthaloyl amino acids (Pht‐amino acids) from amino acid esters, by using o‐methoxycarbonylbenzoyl chloride in anhydrous media, is described. The N‐phthaloyl amino acids and esters from proteins were obtained in high yields.Three N‐phthaloyl amino acids were synthesized for the first time: N‐Pht‐LTrp, N‐Pht‐S‐Bzl‐LCys and N‐Pht‐Nim‐Bzl‐LHis.In the case of some sterically hindered amino acids, LIle and α‐amino‐isobutyric acid, the intermediate N‐(o‐methoxycarbonylbenzoyl) amino acid derivative could be isolated.