微波辐射一步法合成吡喃和吡喃[2,3—c]吡唑衍生物

One Pot Synthesis of Pyrans and Pyrano[2,3-c] pyrazole Derivatives under Microwave Irradiation

芳醛、丙二腈与5,5-二甲基-1,3-环己二酮或3-甲基-1-苯基-2-吡唑啉-5-酮在乙醇溶剂中用哌啶作催化剂,经微波辐射一步合成了2-氨基-3-氰基4芳基-7,7-二甲基-5-氧代-5,6,7,8-四氢苯并吡喃和6-氨基-5-氰基-4-芳基-1,4二氢吡喃[2,3-c]吡唑,反应在2～12min内完成,产率53%～91%.

2-Amino-3-cycano-4-aryl-7,7-dimethyl-5,6,7,8-tetrehydrobenzo[b]pyrans and 6-amino-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles were synthesized by one-step reaction of aromatic aldehydes, malonomtrile and dimedone or 3-methyl-1-phenyl-2-pyrazolin-5-one using piperidine as catalyst under microwave irradiation. The reactions were completed in 2 similar to 12 min in good yields.