TaBr5-catalyzed Biginelli reaction:: one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones under solvent-free conditions

An efficient TaBr5 (5-10 mol %)-catalyzed Biginelli reaction under solvent-free conditions for one-pot syntheses of 3,4-dilhydropyrimidin-2-(] H)-ones (DHPMs) and their thione analogs is reported. The catalyst is stable at room temperature and employed under mild and environmentally friendly conditions. (c) 2007 Elsevier Ltd. All rights reserved.