パラジウム炭触媒によるイソオキサゾール環の還元的開裂反応

抄録

When 5-(p-aminobenzamido)-3, 4-dimethylisoxazole was shaken in hydrogen, in the presence of palladium-carbon, absorption of one mole of hydrogen was observed. The structure (II) was assigned to the product, C₁₂H₁₅O₂N₃, on the basis of ultraviolet and infrared spectra. In confirmation of this structure, the product was converted into 2-(p-aminophenyl)-4, 5-dimethyl-6-pyrimidinol (VI) by heating with ethanolic potassium hydroxide, aqueous ammonia, hydrazine hydrate, or 33% acetic acid. In some of these reactions, hydrolysis of the compound (II) took place simultaneously, giving ammonia, carbon dioxide, p-aminobenzamide, and methyl ethyl ketone as the end products.
Lithium aluminum hydride reduction of the compound (II) afforded 3-methyl-4-(p-aminobenzylamino)-2-butanol (VII), as shown by synthesis.
Thus it was found that the catalytic reduction of 5-(p-aminobenzamido)-3, 4-dimethylisoxazole over palladium-carbon led to cleavage of the ring rather than formation of an isoxazoline derivative.