South African Journal of Chemistry
On-line version ISSN 1996-840X
MIRJALILI, Bi Bi Fatemeh and ZAMANI, Leila. Nano-TiCl4.SiO2: a versatile and efficient catalyst for synthesis of dihydropyrimidones via Biginelli condensation. S.Afr.j.chem. (Online) [online]. 2014, vol.67, pp. 21-26. ISSN 1996-840X.
Nano-TiCl4.SiO2 has been found to be an extremely efficient catalyst for the preparation of 3,4-dihydropyrimidinones/thiones via three-component reactions of an aldehyde, β-ketoester or β-diketone and urea or thiourea under mild conditions. Nano-TiCl4.SiO2 as a solid Lewis acid has been synthesized by reaction of nano-SiO2 and TiCl4. The structural characterization of this acid has been studied by FT-IR (ATR), XRD, SEM and TEM. This process was simple and environmentally benign with high to excellent yields. Furthermore, the catalyst could be recovered conveniently and reused for at least three times.
Keywords : Nano-TiCl4.SiO2; heterogeneous catalyst; multi-component reaction; β-ketoester; β-diketone; urea.