Nucleophilic substitution of protected 2-amino-4-butanoic acid. An easy route to exotic amino acids and conformationally constrained peptides.

The synthesis of a series of novel alpha-amino acids based on the nucleophilic substitution of protected 2-amino-4-bromobutanoic acid (1) is described. Basic, acidic or neutral amino acids can be obtained; chimerical amino acids carrying a coenzyme type structure in the side chain, multifunctional amino acids for the synthesis of cross-linked peptides or dendrimers and conformationally constrained peptides can also be obtained. (C) 1998 Elsevier Science Ltd. ALI rights reserved