Lithium perchlorate efficiently catalyzes the three-component condensation reaction
of aldehyde, β-keto ester and urea in refluxing acetonitrile to afford the corresponding
dihydropyrimidinones in high yields under neutral conditions. LiOTf is also found
to be an efficient catalyst for the synthesis of dihydropyrimidinones from aldehyde,
β-keto ester and urea.
Biginelli reaction - lithium perchlorate - lithium triflate - dihydropyrimidinones