Abstract
Novel one-pot Biginelli-type reaction has been developed. Aromatic and aliphatic aldehydes with β-dicarbonyl compounds and thiourea in the presence of catalytic amount 5 mol% of Yb(OTf)3 at 100° C for 60–90 min under solvent-free conditions proceeded smoothly to afford corresponding dihydropyrimidin-thiones. The yields of the classical Biginelli reaction can be increased from 20–50% to 81–91% while the reaction time was shortened from 18–48 h to 60–90 min. In addition the catalyst can be easily recovered and reused.
Acknowledgment
We thank the National Nature Science Foundation of China and the Science Foundation of East China University of Science and Technology for their financial support.