M. Martinmartinez et al., STUDIES ON THE SYNTHESIS OF SUBSTITUTED 3,6-DIOXOPERHYDROPYRROLO[1,2-A]PYRAZINES AS NONPEPTIDE SCAFFOLDS FOR PEPTIDOMIMETICS, Heterocycles, 45(9), 1997, pp. 1723-1732
Intramolecular reductive amination of 4-keto diesters, derived from Z-
Xaa-Yaa dipeptides, and subsequent gamma-lactamization is a versatile
method for the preparation of 3,6-dioxoperhydropyrrolo[1,2-a]pyrazines
bearing amino acid side chains at C-1, C-4 and C-7 positions, as Xaa-
Yaa-Zaa (Yaa not equal Gly) tripeptide mimetics.