摘要:
Catalytic hydrogenation of 2,3-diphenyl-6-nitroquinoxaline led to the corresponding amine 1 which in turn afforded products 3a-i on reaction with alkoxymethylene derivatives 2a-i. Thermal cyclization of 3b and 3f yielded substituted pyrazinoquinolones 5b and 5f, respectively. Optimal conditions for the successful hydrolysis of ester 5b were found. The structures of all products were deduced from their IR, UV, H-1, and C-13 NMR spectroscopic data.