Triphosgene (60 mg; 0.20 mmol) is added to a solution of methyl-[1-(4-trifluoromethyl-phenyl)-piperidin-4-ylmethyl]-amine (150 mg; 0.60 mmol) and triethylamine (185 μL; 1.33 mmol) in acetonitrile (6 mL). After stirring for 15 minutes a solution of (4-nitro-3-trifluoromethyl-phenyl)-piperidin-4-yl-amine (173 mg; 0.60 mmol, in acetonitrile (10 mL) is added. After 2 hours reaction time at room temperature, the mixture is poured into water (10 m) and the aqueous layer is extracted with ethyl acetate (3×50 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated under reduced pressure. The crude product is purified by column chromatography on silica gel (Ethyl acetate:heptane 8:2) to afford the desired product (267 mg; 0.45 mmol). The structure was confirmed using Protocol II-E. Calculated mass=564; observed mass=564; HPLC retention time=7.73 min.
