To a solution of 1-[2,4-bis(trifluoromethyl)benzyl]piperidine-4-carbaldehyde (520 mg) and N,N-dimethyl-N3-(2-oxo-2,5-dihydro-1,3-thiazol-4-yl)-β-alaninamide (330 mg) in 2-propanol (60 mL) was added piperidinium acetate (223 mg). The reaction mixture was stirred at 80° C. for 4 hr and concentrated. Water was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/methanol). The obtained solid was recrystallized from ethyl acetate/heptane to give the title compound (356 mg).
