Studies on Pyridazine 1, 2-Dioxides. IV. Reduction and Substitution of 4-Nitro-3, 6-dimethylpyridazine 1, 2-Dioxide

抄録

Catalytic reduction of 4-nitro-3, 6-dimethylpyridazine 1, 2-dioxide (II) over palladiumcharcoal in ethanol, the reaction being stopped after absorption of four moles of hydrogen, afforded 4-amino-3, 6-dimethylpyridazine 1-oxide (III) and 5-amino-3, 6-dimethylpyridazine 1-oxide (IV), while after absorption of three moles of hydrogen, II gave 5-hydroxylamino-3, 6-dimethylpyridazine 1-oxide (V) in 38% yield. Heating of II with hydrochloric acid or with hydrobromic acid formed 4-chloro-3, 6-dimethylpyridazine 1, 2-dioxide (IXa) or 4-bromo-3, 6-dimethylpyridazine 1, 2-dioxide (IXb), respectively. When II was treated with acetyl chloride at room temperature for 7 days, 3, 6-dimethyl-4, 5-dichloropyridazine 1-oxide (X), 3-chloromethyl-4-nitro-6-methylpyridazine 1-oxide (XI) and 3-methyl-4, 5-dichloro-6-cyanopyridazine 1-oxide (XII) were obtained besides IXa. In addition to above-mentioned new pyridazine dioxide derivatives (IXa and IXb), 4-methoxy-3, 6-dimethylpyridazine 1, 2-dioxide (XIIIa) and 4-benzyloxy-3, 6-dimethylpyridazine 1, 2-dioxide (XIIIb) were synthesized.