Ring closure of diethyl 2-methoxy-2-[N-(5-amino-1-benzylimidazolyl-4-carbonyl)amino]malonate: Product structures and pathways of product formation

Abstract

Ring closure of the title compound (1) with sodium methoxide in methanol yielded three products, one 5∶6-fused and two 5∶7-fused heterocyclic systems: 9-benzyl-2-methoxycarbonylhypoxanthine (2), 3-benzyl-4,5,7,8-tetrahydro-6-methoxy-6-methoxycarbonyl-6H-imidazo[4,5-e][1,4]-diazepine-5,8-dione (3), and 3-benzyl-4,5,7,8-tetrahydro-6-methoxy-6H-imidazo[4,5-e][1,4]-diazepine-5,8-dione (4). Structures and pathways of formation of all three products have been described. Structures of2 and3 were confirmed by single-crystal X-ray diffraction analyses.