苯丙烯酰苯和甲肼反应的研究

STUDY ON THE REACTION OF CHALCONE WITH METHYLHYDRAZINE

α,β-不饱和醛或酮与单取代肼反应生成Δ-吡唑啉的反应机理,一般认为是通过1,2加成脱水生成腙,然后闭环而得.分离得到的中间体腙在酸性溶液中加热亦可得到Δ-吡唑啉.等人曾报道烯键上无取代基的α,β-不饱和酮与单取代肼反应是经过1,4加成所生成的β-肼基取代的酮闭环而得Δ-吡唑啉.我们在研究苯丙烯酰苯和甲肼的反应中,发现用略微过量的甲肼与苯丙烯酰苯(摩尔比

Reaction of chalcone with methylhydrazine(mol ratio 1:1.05)in an alcoholic solution at temperature lower than-5℃produces an intermediate,1-methyl-3,5-diphenyl-3-hydroxy-pyrazolidine(1)which can be dehydrated to give 1-methyl-3,5-diphenyl-⊿~3-phrazoline(2).The dehydration process can be monitored by IR.and UV spectroscopy and is shown to be first order with respect to 1.