Novel glycine like amino acids from glyco-α-aminonitriles as building blocks for peptide synthesis

Our interest in the glycoaminocyanation reaction led us to apply this methodology to introduce amino acids on a monosaccharide using the N-terminal position. The GAAs described in this paper are characterized by having the amino and carboxylic acid functionalities on a disubstituted position of the saccharide backbone leading to alpha,alpha-disubstituted glycines. These new sugar amino acids showed a restricted conformation involving a spontaneous intramolecular cyclization between the C- and N-terminal positions during hydrolysis or hydrogenolysis to give the corresponding oxopiperazine. Tripeptide mimics were obtained by the introduction of an additional amino acid using one-pot conditions starting from these cyclic by-products under basic media. We demonstrated that these pseudo tripeptides are good candidates for extension of the peptidic scaffold and cyclization. (c) 2007 Elsevier Ltd. All rights reserved.