Health & Environmental Research Online (HERO)


Print Feedback Export to File
1628999 
Journal Article 
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 
Litvic, M; Vecenaj, I; Ladisic, ZM; Lovric, M; Vinkovic, V; Filipan-Litvic, M 
2010 
1 
Tetrahedron
ISSN: 0040-4020 
66 
19 
3463-3471 
WOS:000277967400012 
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(H(2)O)(6)](BF(4))(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 beta-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 Bronsted type catalysts. (C) 2010 Elsevier Ltd. All rights
reserved. 
3,4-Dihydropyrimidinone; Biginelli reaction; Heterocycles; Condensation; Hexaaquaaluminium(III) tetrafluoroborate