Use of N-2-cyanoethylglycine derivatives in the synthesis of peptides of N-2-carboxamidoethylglycine, an isomer of glutamine

Derivatives of N-2-cyanoethylglycine have been employed as coupling components in the synthesis of protected peptides. The nitrile group in N-2-cyano-ethylglycine is readily hydrated by hydrogen bromide treatment with formation of N-2-carboxamidoethylglycine, which is an isomer of glutamine. This reaction, conducted on cyanoethyl intermediates with simultaneous cleavage of appropriate acid-labile protecting groups, was utilized to prepare several free peptides containing N-2-carboxamidoethylglycine residues.