1983 Volume 103 Issue 6 Pages 631-643
Chemical properties of 5-phenylpyrido[2, 3-d]pyridazine 7-oxide (II), obtained in the reaction of 5-phenylpyrido[2, 3-d]pyridazine (I) with m-chloroperbenzoic acid, were studied. Compound II reacted with nucleophiles to give 5-phenyl-8-substituted (R1)-pyrido[2, 3-d]pyridazine or 5-phenyl-8-substituted (R2)-pyrido[2, 3-d]pyridazine 7-oxide. Nucleophiles[Products] ; phosphoryl chloride, sulfuryl chloride, tosyl chloride and potassium carbonate [XVIII (R1=-C1)], benzoyl chloride and potassium cyanide [III (R1=-CN)], sodium hydroxide [XVII (R1=-OH) and I], methylmagnesium iodide, ethyl-(isopropyl) magnesium bromide [IVa, b, c (R2=-CH3, -C2H5, -CH(CH3)2], acetophenone [IVa, in the presence of NaOH ; IVa and VI (R1=-CH2COPh), in the presence of CH3ONa], ethyl cyanoacetate [IX (R1=NC-C^^^〓H-CO2C2H5), in Ac2O ; X (R1=NC-C^^^〓H-CO2CH3) and XI (R1=-OCH3), in the presence of CH3ONa]. Application of Reissert-Henze reaction to IVb gave α-methyl-5-phenyl-8-pyrido[2, 3-d]pyridazinylmethyl benzoate (VII). Reaction of II and dimethyl acethylenedicarboxylate afforded three products (XIIa, b, c), which showed the same molecular formula (C19H15NO5). The structures of XIIa and XIIb were presumed to be methyl 6-methoxycarbonyl-α-oxo-5-phenyl-6H-cyclopenta[b]pyridine-6-ethanoate (XIIa), methyl 5-phenylpyrido[3, 2-c]oxepine-7, 8-dicarboxylate (XIIb), respectively. It is considered that these products are formed by the liberation of nitrogen from 1, 3-dipolar cycloadducts. In these reactions, the poor yield of the expected product was accompanied in majority of cases with viscous substance with unknown structure.
