Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
RUSSOWSKY, Dennis et al. Multicomponent Biginelli's synthesis of 3,4-dihydropyrimidin-2(1H)-ones promoted by SnCl2.2H2O. J. Braz. Chem. Soc. [online]. 2004, vol.15, n.2, pp. 165-169. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532004000200002.
The ability of SnCl2.2H2O as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, ethyl acetoacetate and urea or thiourea is described. The reaction was carried out in acetonitrile or ethanol as solvents in neutral media and represents an improvement of the classical Biginelli protocol and an advantage in comparison with FeCl3.6H2O, NiCl2.6H2O and CoCl2.6H2O which were used with HCl as co-catalyst. The synthesis of 3,4-dihydropyrimidinones was achieved in good to excelent yields.
Keywords : Biginelli reaction; multicomponent reaction; dihydropyrimidinones; tin(II) chloride hydrate; Lewis acid.