A facile four-component Gewald reaction under organocatalyzed aqueous conditions

Abstract

In the presence of water and triethylamine, a four-component process involving ethyl cyanoacetate, an α-methylene carbonyl compound, a primary or a secondary amine, and elemental sulfur leads to efficient room-temperature formation of 2-amino-3-carboxamide derivatives of thiophene in short time periods. The products, which precipitate from the reaction mixtures, are easily obtained by simple filtration and recrystallization from ethyl acetate/hexanes.