Simple and Efficient Three Component One-Pot Synthesis of Pyrazolo[1,5,<i>a</i>]Pyrimidines

Abstract

A series of novel 5-(2-bromophenyl)-N-cyclohexyl-2-(methylthio)-6-nitro-7-phenyl-4,7-dihydropyrazolo [1,5-a] pyrimidine-3-carboxamides were synthesized by a one-pot reaction of 5-amino-N-cyclohexyl-3-(methylthio)-1H-pyrazole-4-carboxamide, 1-(2-bromophenyl)-2-nitroethanone and aryl aldehydes in the presence of boric acid in water at refluxing temperature. Structures of compounds were demonstrated by Fourier transform infrared, 1H NMR, 13C NMR and elemental analysis. The advantages of this method are mild reaction condition, good yields, and operational simplicity.