Co(OAc)2-catalyzed tandem reaction: Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones from β-keto ester, substituted aldehydes and urea/thiourea using microwaves under solvent free condition

Cobalt (II) acetate efficiently catalyzes the three-component coupling of β-keto ester, substituted arylaldehyde and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones/thiones respectively, the new protocol for the Biginelli reaction under microwave irradiation works in the absence of solvent, the yields are high and the reactions go to completion within one minute