Ultrasound promoted ZrCl(4) catalyzed rapid synthesis of substituted 1,2,3,4-tetrahydropyrimidine-2-ones in solvent or dry media.

Sonication of aromatic aldehydes, urea and ethyl acetoacetate in presence of solvent (ethyl alcohol) or solvent-less dry media (bentonite clay) supported-zirconium (IV) chloride (ZrCl(4)) as catalyst at 35 kHz gives 6-methyl-4-substitutedphenyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl esters proficiently in high yields.