Abstract
The one-pot condensation of aromatic aldehydes, β-dicarbonyl compounds, and urea or thiourea in the presence of H2SO4 supported on silica gel or alumina (80% m/m) in refluxing n-hexane produces 3,4-dihydropyrimidin-2(1H)-ones and their sulfur derivatives in high to excellent yields.
The authors gratefully appreciate the financial support of this work by the research council of Urmia University.
Notes
a All reactions were carried out with 1 mmol of benzaldehyde in 5 mL of solvent under reflux conditions.
a All reactions were carried out with a molar ratio of aldehyde/β-dicarbonyl/urea (thiourea) of 1:1:1.2 in refluxing n-hexane.
b Yields refer to isolated pure products.
a The reactions with H2SO4/SiO2 or Al2O3 and silica sulfuric acid were carried out in refluxing n-hexane and ethanol, respectively.