A greener approach for the synthesis of 3-cyanoacetamide pyrrole catalyzed by amorphous carbon-supported sulfonic acid

Abstract

Amorphous carbon-supported sulfonic acid (AC–SO₃H) is known as a new-generation solid catalyst with exceptional activity in organic synthesis. We report here the synthesis of sulfonated amorphous carbon, that possesses sulfonic acid groups, via the partial carbonization and then sulfonation of rice husk. The presence of –SO₃H groups on the surface of the amorphous carbon significantly increased the catalytic activity in organic synthesis. In this study, the catalytic activity of AC–SO₃H in the synthesis of 3-cyanoacetamide pyrrole from 1,3-diketones, primary amines, phenylglyoxal monohydrate, and malononitrile in acetone was assessed. We investigated the influence of the amine derivatives on the reaction outcome and the formation of by-products during the reaction. The main product was obtained in yields of up to 67%. The activity of the catalyst was also evaluated through a leaching test, whilst the recovery and reuse efficiency of the catalyst was also studied, with a negligible reduction in activity observed.