Ultrasound Assisted Synthesis of 1,5-Disubstituted Pyrazole using Cu(I) Catalyst

Abstract

A new efficient and convenient approach towards the synthesis of pyrazole is described. The α,β-unsaturated cyanoesters were obtained from substituted benzaldehyde and ethyl cyanoacetate by reported methods. 1,5-Disubstituted pyrazoles were synthesized from α,β-unsaturated cyanoester and phenyl hydrazine using sodium ethoxide as a base in the presence of 10 mol % Cu(I) catalyst in high yields within 75-90 min under ultrasound irradiation at 60 ºC. The reaction rate is enhanced tremendously under ultrasound irradiation as compare to conventional methods with improved yields are recorded.