3-Trifluoromethylphenol (5 mmoles) and subsequently 3,3-dichloroacrolein (5 mmoles) are added to a mixture consisting of a 4-trifluoromethylbenzamidinium acetate (5 mmoles), sodium carbonate (40 mmoles) and acetonitrile (35 ml), which is stirred under reflux. The reaction mixture is stirred for 20 hours under reflux and subsequently cooled down to ambient temperature and filtered through silica. The organic phase is washed with ethyl acetate and concentrated in vacuo. The residue is purified by chromatography on Al2O3 (petrol ethers/ethyl acetate: 2/1) to yield 1.1 g (60%) of the pure product having a melting point of 66-67° C.
