Heterocyclic imines and amines. Part XVII. Confirmation of the structures of two aminopyridazinones
Abstract
Only the 3-substituent of 4-amino-6-chloro-3-methoxypyridazine was attacked on acidic or alkaline hydrolysis or by thiourea in boiling ethanol. With potassium acetate in acetic acid at 170°, however, 5-amino-6-methoxy-pyridazin-3(2H)-one was obtained, together with 4-amino-1,2-dihydropyridazine-3,6-dione. Heating the former product with hydrazine gave 5-amino-6-hydrazinopyridazin-3(2H)-one. A mixture of the two pyridazinones simulated the product from interaction of 3,6-dimethoxypyridazine and hydrazine, so confirming previous tentative conclusions. Heating 4-amino-6-chloro-3-hydrazinopyridazine with potassium acetate in acetic acid gave 8-amino-6-chloro-3-methyl-s-triazolo[4,3-b]pyridazine.