Peptide bond formation by intermolecular aminolysis of d-glucopyranosyl esters of amino acids

Abstract

The reaction of HO-protected and -unprotected d-glucopyranosyl esters of N-acylamino acids (Gly, Ala, Phe) with glycine and phenylalanine methyl esters in N, N-dimethylformamide at 38° and dichloromethane at 40°, respectively, led to rupture of the C-1 ester bond and formation of the corresponding N-acyldipeptide methyl ester. The relative reactivity of the C-1 ester bond toward aminolysis was greatly influenced by the structure of the amino acid nucleophile, the nature of the aglycon side-chain group, and the anomeric configuration of the d-glucopyranosyl ester involved. Evidence for a substantially lower acylating efficiency of the ester at C-2, as compared to that at C-1, was obtained by aminolysis of two fully acetylated 2- O-(acylaminoacyl)-β- d-glucopyranoses. Treatment of 1- O-(glycylglycylglycyl)-β- d-glucopyranose with phenylalanine methyl ester in N, N-dimethylformamide led to parallel hydrolysis and intermolecular aminolysis, to give the tripeptide and tetrapeptide methyl ester.