To a stirred solution of 2-(trifluoromethyl)aniline (0.5 mL, 4.20 mmol) in dichloromethane (10.0 mL) was added 4-chlorocarbonylpiperidine-1-carboxylic acid tert-butyl ester (1.000 g, 4.00 mmol). The reaction mixture was stirred at ambient temperature for 10 minutes, then followed by the addition of triethylamine (0.6 mL, 4.20 mmol). The reaction mixture was stirred at ambient temperature for another 10 minutes. Water (5.0 mL) was added to the mixture and the organic phase separated and washed with saturated NaCl (10 mL), dried over MgSO4 and then concentrated in vacuo. The obtained crude product was purified by column chromatography to yield the desired product, 4-(2-trifluoromethylphenylcarbamoyl)piperidine-1-carboxylic acid tert-butyl ester, in 30% yield (0.450 g). 1H NMR (300 MHz, CDCl3) δ 7.97 (d, J=8.0 Hz, 1H), 7.61 (s. 1H), 7.53 (d, J=7.9 Hz, 1H), 7.47 (t, J=7.5 Hz, 1H), 7.18 (t, J=7.6 Hz, 1H), 4.13-4.04 (m, 2H), 2.77-2.69 (m, 2H), 2.44-2.34 (m, 1H), 1.87-1.93 (m, 2H), 1.70-1.57 (m, 2H), 1.40 (s. 9H). MS (ES−) m/z 371 (M−1).
