Synthesis of Pyridazine Derivatives. XI. Synthesis of N1-4-Pyridazinylsulfanilamide Derivatives

Reactions of 4-amino-3, 6-dichloropyridazine (I) with caustic alkali in methanol and of 4-amino-3, 6-dimethoxypyridazine (III) with acetylsulfanilchloride in pyridine were studied. In the former reaction, the reaction sequence to the formation of (III), 4-amino-6-chloro-(IV) and 4-amino-6-methoxy-3(2H) pyridazinone (V) was clarified. In the latter condensation reaction, it was found by thin-layer chromatography that 2-p-acetylaminobenzenesulfonyl-5-amino-6-methoxy-3(2H) pyridazinone (XI), two demethylated compounds (IX and X) of N1-(3, 6-dimethoxy-4-pyridazinyl)-N4-acetylsulfanilamide (VIII) as well as the main product (VIII) were produced and their structures were proved. The demethylation reactions of VIII and its deacetylated compound (XII) with pyridine hydrochloride were examined.