CONDENSATION AND CYCLIZATION REACTIONS OF THSALAZINYLTHIO]-6-(P-TOLYL)-4,5-DIHYDROPYRIDAZINE

3-Hydrazinopyridazine (5) has been synthesized by a four-step route. T he hydrazine (5) on treatment with ethyl acetoacetate and/or acetylace tone undergo cyclization to afford pyrazolone derivative (6) and 3-(py razol-1-yl)pyridazine derivatives (7) respectively. Condensation of 5 with ethyl chloroacetate and/or diethyloxalate furnish 1,2,5-triazino- fused ketones (8 and 9) of the tide pyridazine respectively. Also, con densation of 5 with aromatic aldehydes and/or acetic anhydride afford 3-aryl- and 3-methyl substituted 1,2,5-triazolo-fused pyridazines (11 and 13) respectively. Diazotization of 5 with nitrous acid give 3-azid opyridazine (14) which undergo thermal cyclization to furnish the tetr azolopyridazine (15).