South African Journal of Chemistry
On-line version ISSN 1996-840X
WU, Ming Shu; HE, Ping and ZHANG, Xiang Zhu. An environmentally friendly solvent-free synthesis of 3,4-dihydropyrimidinones using a p-aminobenzene sulfonic acid catalyzed Biginelli reaction. S.Afr.j.chem. (Online) [online]. 2010, vol.63, pp. 224-226. ISSN 1996-840X.
Anhydrous p-aminobenzene sulphonic acid mediated solvent-free protocol is described for the synthesis of dihydropyrimidi-nones by the cyclocondensation of aldehydes, β-ketoesters and urea/thiourea. Yields obtained are significantly higher than those obtained utilizing classical Biginelli reaction conditions.
Keywords : Anhydrous p-aminobenzene sulphonic acid; 3,4-dihydropyrimidinones; Biginelli reaction.