Synthesis, reactions and spectroscopy of 3-benzoyl-6-phenylpyridazines of expected biological activity

Oxidative decyanation of phenyl(6-phenylpyridazin-3-yl)acetonitrile (1) in methanol yielded 3-benzoyl-6-phenylpyridazine (2). Phenyl(6-phenyl-pyridazi n-3-yl)methanol (3) h as been obtained via NaBH4 reduction of ketone 2. Rea ction of 2 with hydroxylamine or its O-alkyl analogue has been found to yie ld 3-benzoyloxime-6-phenylpyridazine (4) and alkyloximes (5), respectively Treatment of 4 with a mixture of acetic acid and sulfuric acid afforded ket one 2 again and not the rearranged products (6 or 7). Beckmann rearrangemen t has however been achieved for 3-benzoyl(O-ethyloxime)-6-phenylpyridazine (5a) and oxime 4 giving solely 3-carboxanilide-6-phenylpyridazine (6), 4-Be nzoyloxime-3-phenyl-6-chloropyridazine (17) has been synthesized from the c orresponding ketone 16.