Naslov
First application of Hexaaquaaluminium(III) tetrafluoroborate as a mild, recyclable, non- hygroscopic acid catalyst in organic synthesis: A simple and efficient protocol for the multigram scale synthesis of 3, 4-Dihydropyrimidinones by Biginelli reaction

Autori
Litvić, Mladen ; Večenaj, Ivana ; Mikuldaš Ladišić, Zrinka ; Lovrić, Marija ; Vinković, Vladimir ; Filipan-Litvić, Mirela

Izvornik
Tetrahedron (0040-4020) 66 (2010); 3463-3471

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
3; 4-dihydropyrimidinone; Biginelli reaction; heterocycles; condensation; hexaaquaaluminium(III) tetrafluoroborate

Sažetak
For the first time hexaaquaaluminium(III) tetrafluoroborate has been used as a mild acid catalyst in organic synthesis. A simple method of its preparation based on the reaction of aluminium triisopropoxide and tetrafluoroboric acid in isopropanol afforded catalyst of high purity and activity. The three component Biginelli condensation of acetoacetate esters, urea and aldehydes catalyzed by 10 mol% of [Al(H2O)6](BF4)3 in refluxing acetonitrile afforded 3, 4- dihydropyrimidonones in good to high yields on multigram scales. The tolerance to acid sensitive reactants such as thienyl and furyl carbaldehydes, applicability to sterically hindered β-ketoesters and simple recyclability without losing catalytic activity make this catalyst as good replacement to literature methods. The mechanism of the reaction includes formation of the so called “ureido- crotonate” rather than corresponding acylimino intermediate as found with Brønsted type catalysts.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA