Citric acid as a green and naturally biodegradable catalyst promoted convenient synthesis of polysubstituted dihydro-2-oxypyrrole derivatives via four-condensation reaction of dialkylacetylenedicarboxylate, formaldehyde and amines

Abstract

Citric acid is found to be a green and naturally biodegradable catalyst for one-pot, four-condensation of dialkylacetylenedicarboxylate, formaldehyde and amines (aromatic and aliphatic) to afford the corresponding polysubstituted dihydro-2-oxypyrrole derivatives under ambient temperature. The remarkable features of this one-pot procedure are green and low-cost catalyst, high yields, short reaction times, simplicity of operation and work-up procedures, the availability and easy to handle of this solid acid catalyst, avoidance of hazardous or toxic catalyst and mild reaction conditions.