SYNTHESIS OF NEW PYRIDAZIN- 6-ONES, PYRIDAZIN-6-IMINES, 4-PYRIDAZINALS, AND PYRIDINES

3-Dimethyl-1-[3-methyl-(4H)-5-phenylimidazol[2,1-b]thiazol-2-yl]prop-2-enone 4 couples smoothly with benzenediazonium chloride to yield propanal 5 which is a key intermediate for the synthesis of pyridazinones 9–13, 16 and pyridazine-6-imine 8, 19. Pentadienonitrile 18 was converted into pyridine-3-carbonitrile 20 on refluxing in ethanolic sodium ethoxide solution. Pyrazole 24 was synthesized from the reaction of 5 with 1-chloro-2-phenylhydrazono propan-2-one 22.