The synthesis of pyrrolo[1,2-a]pyrazin-1(2H)-ones and pyrrolo[1,2-b]pyridazin-6(5H)-ones

The pyrrolo[1,2-a]pyrazin-1(2H)-ones (10), (11), (12) and (13) and the pyrrolo[1,2-b]pyridazin-6(5H-one (18) were prepared either a) directly by Chichibabin quaternisation-cyclisation of the corresponding methoxy- methylpyrazine or pyridazine or b) by hydrogen halide hydrolysis of methoxypyrrolo[1,2-a]pyrazines and methoxypyrrolo[1,2-b]pyridazines. Protonation studies and some reactivity of the systems are discussed