Synthesis of Peptides with α,β‐Dehydroamino Acids, I. Synthesis of N‐Benzyloxycarbonyl and N‐Trifluoroacetyl Dipeptides of Dehydroalanine and Dehydrophenylalanine

Abstract
Condensation of amides of N‐(benzyloxycarbonyl)‐ and N‐(trifluoroacetyl)amino acid with pyruvic and phenylpyruvic acid yields, in the presence of p‐toluenesulfonic acid as a catalyst, N‐(benzyloxycarbonyl)‐ and N‐(trifluoroacetyl)dehydro dipeptides with C‐terminal Δ Ala and ΔPhe, respectively (Table 2 and 3).