Synthesis of 9-membered dilactams derived from 1,3-diaminopropionic and glutamic acids.

Previously unknown 9-membered bridged dipeptides derived from l or d isomers of 1,3-diaminopropionic acids and l-glutamic acid were synthesized using aminoacyl incorporation reaction. Key intermediates containing internal pyroglutamyl moiety were prepared via side chain to backbone cyclization of related protected dipeptide derivatives of glutamic acid.