ZnO NANOROD-CATALYZED THREE-COMPONENT REACTION OF EUPARIN, ALDEHYDE, AND DIALKYL ACETYLENEDICARBOXYLATE: GREEN SYNTHESIS OF CHROMENE DERIVATIVES

Abstract

New chromene derivatives, 9H-furo[2,3-f]chromene-7,8-dicarboxylates, have been synthesized in high yields by a three-component reaction of euparin (isolated from Petasites hybridus), an aldehyde, and dialkyl acetylenedicarboxylate in the presence of PPh₃ and catalytic amount of ZnO nanorods under solvent-free conditions at room temperature. ZnO nanorods showed a strong effect on improving the yield of the desired products. Chromene derivatives can be easily separated from the reaction mixture in a simple work-up, and the catalyst may be recovered and reused without considerable loss of activity.