Synthesis of N-Aryl-2-(1′,6′-dihydro-6′-pyridazinone-3′-carbonyl) Thiosemicarbazides and Their Related Heterocyclic Compounds

Dihydro-3-hydrozinocarbonyl-6-pyridazinone（compound 2） were prepared from α-ketoglutaric acid and hydrazine hydrate. A series of N-aryl-2-（1′,6′-dihydro-6′-pyridazinone-3′-carbonyl） thiosemicarbazides 3a3f were synthesized from the reaction of aryl isothiocyanates with compound 2. The terminal compounds 1,3,4-thiadiazole, 1,3,4-oxadiazole and 1,2,4-triazol-5-thione derivatives were cyclized from compounds 3a3f. Their structures were confirmed by IR, 1H NMR, MS and elemental analyses.