不稳定中间体1-甲基-3,5-二苯基吡唑烷醇-3脱水反应的光谱研究

The Spectroscopic Study of the Dehydration of 1-Methyl-3,5-diphenyl-3-hydroxypyrazolidine

α,β-不饱和醛酮与单取代肼反应的产物是吡唑啉。据文献报道,反应是经过腙关环而得产物[1]。我们的实验发现,苯丙烯酰苯(Ⅰ)与甲肼(Ⅱ)(1:1.05)在-5℃以下反应可以分离到一个白色不稳定的中间体1-甲基-3,5-二苯基吡唑烷醇-3(Ⅲ)。它在-75℃稳定,温度升高时缓慢脱水生成产物卜甲基-3,5-二苯基吡唑啉(Ⅳ)[2]。

The reaction of chalcone with methylhydrazine produces a new compound,1-methyl-3,5-diphenyl-3-hydroxypyrazoline(Ⅲ).The unstable intermadiate can be dehydrated into pyrazoline.The dehydration process can be monitored by IR and UV,and is shown to be first order with respect to(Ⅲ).The absorption at 1680cm^(-1) in compound(Ⅲ )is assigned to the structure of ■.