Synthesis of pyrazino[1,2-a]benzimidazol-1(2H)ones via a microwave assisted Buchwald–Hartwig type reaction

A convenient synthesis of substituted pyrazino[1,2-a]benzimidazol-1(2H)ones starting from 3,5-dichloropyrazinones has been accomplished. Various 3-anilino-pyrazinones were easily converted to the desired tricyclic structures by applying a microwave assisted Buchwald–Hartwig type cyclization.