Abstract
A novel ionic liquid, 3‐carboxymethyl‐1‐methylimidazolium bisulfate (CMImHSO4), was synthesized and used as a recyclable catalyst for the Biginelli reaction under solvent‐free conditions. High yields of various substituted 3,4‐dihydropyrimidin‐2(1H)‐ones (or thiones) were obtained. The ionic liquid can be recovered and recycled easily without loss of activity.
Acknowledgment
We are grateful to the Education Foundation of Zhejiang Province (Project No. 20040847) for financial support.