Carbonyldiimidazole (CDI) Mediated Synthesis of Nα-Protected Amino Acid Azides: Application to the One-pot Preparation of Ureidopeptides

Synthesis of Nα-protected amino acyl azides starting from corresponding acids via the carbonyldiimidazole (CDI) activation is described. The protocol is extended for a one-pot preparation of ureido peptides that circumvents the isolation of acyl azide and isocyanate intermediates. The reaction was accomplished without using any additives and base. The protocol is simple, clean, high yielding and free from racemization.