REACTIVITY OF METHYL(3,6-DICHLOROPYRIDAZIN-4-YL)ACETATE TOWARDS NUCLEOPHILES

Methyl (3,6-dichloropyridazin-4-yl)acetate, prepared from methyl (3,6-dihydroxypyridazin-4-yl)acetate by chlorination with phosphorus oxychloride, was used for studies of nucleophilic displacement reactions. Cl at position 6 was displaced with hydrazine. With diluted hydrochloric acid both Cl were diplaced with the 6-oxo isomer predominating. By turning the aromatic ring of pyridazine into an o-quinoid system, the Cl at position 3 became mobile. Cyclization of (6-hydrazino-s-triazolo-[4,3-b]pyridazine-7-yl)acetic acid hydrazide gave 6-aminopyrrolo[3,2-e]s-triazolo[4,3,-b]-pyridazin-7(8H)one. Compounds were tested for pharmacological activity.