EPIMERIZATION-FREE PEPTIDE FORMATION FROM CARBOXYLIC-ACID ANHYDRIDES AND AZIDO DERIVATIVES

Conversion of C-terminal carboxy groups of N-protected alpha-amino aci ds to the corresponding 3,5-dinitrobenzoyl mixed anhydrides, followed by treatment with alpha-azido eaters and trialkylphosphines, affords g ood yields of peptides, without appreciable formation of epimers even for reactions involving Phe-Val and Val-Val couplings and/or Nbenroyl alpha-amino acids.