采用丙烯酸酯基桥联γ-取代的β-二酮分别与水合肼和盐酸羟胺反应,合成并表征了含有长链和共轭结构的吡唑和异嗯唑类新化合物,研究了不同溶剂对反应的影响.实验结果表明,当用乙醇为反应溶剂时,γ-取代的β-二酮与盐酸羟胺反应得到异嗯唑化合物;与水合肼反应不能得到目标吡唑化合物,而得到α,β-不饱和双键被还原的酰肼化合物;当用乙酸作为反应溶剂时,γ-取代的卢一二酮与水合肼反应得到目标毗唑类化合物.进一步探讨了生成酰肼化合物的反应历程。
Synthesis and characterization of a series of long-chain conjugated pyrazoles and isoxazoles were achieved through reaction the of acrylic ester bridged γ-substituted β-diketone with hydrazine hydrate and hydroxylamine hydrocholoride respectively. The influence of different solvents on the reactions was studied and the results reveal that the reaction outcome depends on the solvent. When alcohol was used as the solvent, isoxazoles were obtained via reaction of γ-substituted β-diketone and hydroxylamine hydrocholoride, while no target pyrazole compounds but α,β-saturated hydrazines were formed via reaction of γ-substituted β-diketone and hydrazine hydrate. When using acetic acid as the solvent, the target pyrazole compounds were obtained. The reaction mechanisms for the formation of α,β-saturated hydrazines were discussed.