ZnO nanoparticles as an efficient catalyst for the selective synthesis of 4-hydroxychromenes via the reaction of salicylaldehydes with dimethyl or diethyl acetylenedicarboxylate in [bmim]BF4

Abstract

ZnO nanoparticles as a highly effective heterogeneous base catalyst selectively catalyzes the reaction between salicylaldehydes and dialkyl acetylenedicarboxylates in ionic liquid [bmim]BF4 to obtain 4-hydroxy-4H-chromenes in high to excellent yields. The advantages of this method include the selectivity of reaction, one-pot procedure, mild reaction conditions, operational simplicity, and use of inexpensive and non-toxic catalyst. .