A fast and highly effcient protocol for synthesis of dihydropyrano[2,3]pyrazole compounds using acidic ionic liquid 3-methyl-1-sulfonic acid imidazolium chloride ([Msim]Cl) as catalyst and green solvent

Abstract

A new, effcient, and environmentally benign protocol for the one-pot, fourcomponent synthesis of dihydropyrano[2,3-c]pyrazoles by condensation of ethylacetoacetate, hydrazine hydrate, aromatic aldehyde, and malononitrile catalyzed by 3-methyl-1-sulfonic acid imidazolium chloride ([Msim]Cl) as an ecofriendly catalyst with high catalytic activity and reusability at 30ffC under solvent-free conditions is reported. The reactions proceed to be completed within 5-15 min in 87-97% yield.