Abstract

SYNTHESIS OF SUBSTITUTED ETHYL ?-CYANOCINNAMATES FROM 1-CYANOACETYL-3,5-DIMETHYLPYRAZOLE

*Madhavi Kuchana

ABSTRACT

A simple and efficient one-pot synthesis of substituted ethyl α-cyanocinnamates from 1-cyanoacetyl-3,5-dimethylpyrazole was reported. In the present study, the title compounds were prepared by refluxing 1-cyanoacetyl-3,5-dimethylpyrazole and substituted benzaldehydes in absolute ethyl alcohol containing catalytic amount of piperidine for about 5 to 10 minutes. In this reaction, 1-cyanoacetyl-3,5-dimethylpyrazole first reacts with O-nucleophile ethoxide, the conjugate base of ethanol, leading to insitu generation of ethyl cyanoacetate and it was simultaneously condensed with substituted bezaldehyde in presence of piperidine. This synthetic route was proved to be clean and efficient with high yield of product. Hence, 1-cyanoacetyl-3,5-dimethylpyrazole was recognized as cheap, effective starting material for the knoevenagel condensation and more reactive than ethyl cyanoacetate. Total eight compounds were synthesized through this synthetic route and they were characterized by their physical and spectral data.

Keywords: 1-cyanoacetyl-3,5-dimethylpyrazole, Knoevenagel condensation, ethyl ?-cyanocinnamates.