Synthesis of Peptides with α,β‐Dehydroamino Acids, II. Synthesis of <i>tert</i>‐Butyloxycarbonyldipeptides of Dehydroalanine and Dehydrophenylalanine

Abstract

Abstract Condensation of amides of Boc‐amino acids 3) with pyruvic acid leads to Boc‐dipeptides 1 – 3 of dehydroalanine and 1‐Boc‐5‐alkyl‐2‐methyl‐4‐oxo‐2‐imidazolidinecarboxylic acids 8 – 10 . The amides, however, do not condense with phenylpyruvic acid. Boc‐dipeptides of dehydroalanine ( 1 – 3 ) and dehydrophenylalanine ( 4 – 7 ) are synthesized using (Boc) 2 O and dehydrodipeptides with a free unmasked N‐terminal amino group.