Microwave Assisted Synthesis of Pyrazolo[1,5-a]pyrimidine, Triazolo[1,5-a]pyrimidine, Pyrimido[1,2-a]benzimdazole, Triazolo[5,1-c] [1,2,4]triazine and Imidazo[2,1-c] [1,2,4]triazine

摘要

Background: This paper describes the synthesis of novel fused heterocycles, from the reaction 2-cyano-N-cyclohexyl-3-acrylamide derivatives 5a-f with nitrogen nucleophilic reagents, which carried out under microwave irradiation. Reactivity of 3 towards diazonium amines salts to afford hydrazones undergo cyclization to give amino pyrazole and the fused heterocyclic compounds incorpo-rating cyclohexyl moiety. The synthesized compounds excellently utilized microwave irradiation in short time and high yield. Methods: Synthesis of Fused heterocycles derivatives from 2-cyano-N-cyclohexyl acetamide utilizing Microwave irradaition. Results: Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-N-cyclohexyl acetamide (3) with appropriate aldehydes to afford the corresponding acrylamide derivatives 5a-f under microwave irradiation. Acrylamides 5 reacts with hydrazine derivatives affording the corresponding pyrazole derivatives 7a and 7b, furthermore the treatment of acrylamides 5 with 2-amino benzimidazole, amino pyrazole, and aminotriazole derivatives to gives corresponding pyrimido[1,2-a]benzimdazole 10, pyrazolo[ 1,5-a]pyrimidine 12 and triazolo[1 ,5-a]pyrimidine 14; respectively in good yield. Reactivity of 3 towards diazonium amines salts afforded hydrazones derivatives, which undergo cyclization to give the corresponding derivatives 19a and the fused pyrazolo[5,1 -c][1,2,4]triazine 22,triazolo[5,1 -c][ 1,2,4]triazine 24 and imidazo[2,1 -c][ 1,2,4]triazine 28 incorporating cyclohexyl moiety. Conculsion: In this investigation, we have synthesized innovative pyrimido[ 1,2-a]benzimdazole, and triazolo[1,5-a]pyrimidine,pyrazolo[ 1,5-a]pyrimidine, 2-amino benzimidazole, amino pyrazole, aminotriazole, fused pyrazolo[5,1 -c][ 1,2,4]triazine, triazolo[5,1 -c][ 1,2,4]triazine and imidazo[2,1-c][1,2,4]triazine derivatives incorporating cyclohexyl moiety utilizing microwave irradiation. The compounds were obtained under microwave reaction in excell