Imidazol[1,2-a]pyrazine-3,6-diones derived from [alpha]-amino acids: A theoretical mechanistic study of their formation via pyrolysis and silica-catalyzed process

A theoretical mechanistic study of the formation of imidazo[1,2-a]pyrazine-3,6-diones derived from alpha-amino acids using pyrolysis and silica-catalyzed process is presented. The cyclocondensation of N-acylated diketopiperazincs into bicyclic amidines is endothermic for Gly and exothermic for [alpha]-aminoisobutic acid.