Rearrangement of ethyl 2-(3-amino-4-pyridinyl)hydrazinecarboxylate hydrochloride to 1-amino-1H-imidazo[4,5-c]pyridin-2(3H)one hydrochloride

In a study of the synthesis (unsuccessful) of pyrido3,4-e]-as-triazino-3 (4H)one (6) , the acidification of 2-(3-amino-4-pyridyl)hydrazinecarboxylate hydrochloride (8) unexpectedly gave 1-amino-1H-imidazo4,5-c]pyridin-2(3H) one hydrochloride (10). The isolation and characterization of 10 has been described.