A new protocol to synthesize 1,4-dihydropyridines by using 3,4,5-trifluorobenzeneboronic acid as a catalyst in ionic liquid:: synthesis of novel 4-(3-carboxyl-1H-pyrazol-4-yl)-1,4-dihydropyridines

3,4,5-Trifluorobenzeneboronic acid catalysed, ionic liquid mediated facile synthesis of 4-pyrazolyl 1,4-dihydropyridines at room temperature by the cyclocondensation of ethyl 3-aminocrotonate, pyrazole aldehyde and a beta-keto ester is reported. The procedure adopted was found to be eco-benign, facile at room temperature and better than the conventional, [bmim]Cl mediated and InCl3 catalysed, [bmim]Cl mediated 1,4-dihydropyridine syntheses. (C) 2005 Elsevier Ltd. All rights reserved.