Abstract
The synthesis of 3,4-dihydropyrimidin-2(1H)-one phosphonates by the Biginelli reaction of β-ketophosphonates, aldehydes and urea derivatives was studied under microwave conditions. The molar ratio of the starting materials, temperature and reaction time was changed to find the optimal parameters. An efficient zinc-triflate-catalyzed solvent-free method was developed. The condensation was extended and carried out with different β-ketophosphonates, aromatic or aliphatic aldehydes and urea derivatives.