Synthesis and reactions of some 6-aryl and 2,6-diaryl-4-(4'-antipyrinyl)-2,3,4,5-tetrahydropyridasin-3-ones and screening for their antibacterial activities

Some new pyridazinone derivatives（3） were synthesized through addition of antipyrin to β-aroylacrylic acids （1） followed by cyclization of the adducts. Reactions of 3 with ethyl bromoacetate,benzenesulfonyl chloride, benzoyl chloride and POClgive N-substituted products and monochlorosub-stituted pyridazines （4）, respectively. The reactions of the latter with thiourea give unexpected dithio-derivatives（5）, which react with phenylhydrazine to give pyrazolopyridazino pyridazine derivatives （6）.Reactions of 2 with NHOH in ethanol and pyridine afford oxime and oxazinone derivatives 7 and 8,tespectively. The antibacterial activities of several compounds were screened.