碱性离子液体催化“一锅法”合成1,4-二氢吡喃并[2,3-c]吡唑

在碱性离子液体氢氧化1-丁基-3-甲基咪唑(bmim]OH)催化作用下,由芳香醛、丙二腈、苯甲酰乙酸乙酯和肼或苯肼"一锅法"合成了一系列1,4-二氢吡喃并2,3-c]吡唑化合物.实验中考察了催化剂、反应温度、催化剂用量、溶剂对反应的影响,确定了最优反应条件,给出了可能的反应机理.此外催化剂可以方便地收回,且循环使用四次其催化活性并没有显著降低.目标产物经过了1H NMR,IR,MS和元素分析确证.合成方法条件温和、反应时间短、产率高且对环境友好.

One-Pot Synthesis of 1,4-Dihydropyrano[2,3-c]pyrazoles Catalyzed by Basic Ionic Liquids

A series of 1,4-dihydropyrano2,3-c]pyrazoles were synthesized via four-component one-pot reaction of aromatic aldehyde,malononitrile,ethyl benzoylacetate and hydrazine or hydrazinobenzene.1-Butyl-3-methyl imidazolium hydroxide(bmim]OH) was used as basic ionic liquid catalyst.The effect of catalyst,reaction temperature,catalyst amount and solvent on the yield were investigated.The optimum reaction condition was determined and the possible mechanism was proposed.Besides,the catalyst could be recovered conveniently and reused for at least four times without evident loss of activity.Theproducts were identified by 1H NMR,IR,MS techniques and elemental analysis.The present methodology offers several ad-vantages such as milder reaction condition,shorter reaction time,excellent yield and environmental friendliness.