Novel biocompatible glucose-based deep eutectic solvent as recyclable medium and promoter for expedient multicomponent green synthesis of diverse three and four substituted pyrazole-4-carbonitrile derivatives

Abstract

A novel biocompatible glucose-based deep eutectic solvent (DES) is reported for the first time in the multicomponent synthesis of diverse three and four substituted pyrazole-4-carbonitrile derivatives under catalyst-free condition without using any harmful organic solvent even for purification of the products. The desired products were obtained with high degree of diversity from the reaction of malononitrile, aromatic aldehydes and various hydrazine derivatives as nitrogen source at room temperature within short reaction times and good to excellent product yields. The deep eutectic solvent was also recycled and reused at least four times with only a slight loss of efficiency. A plausible mechanism was also proposed indicating the role of DES hydrogen bonding in the reaction promotion.