To a solution of 2-(trifluoromethyl)piperazine (135 mg, 0.876 mmol) in dichloromethane (6 mL) was added di-tert-butyl dicarbonate (0.224 mL, 0.963 mmol) and the reaction mixture was stirred for 3 hours at room temperature. After completion of the reaction, the mixture was concentrated and the residue was purified by silica gel column chromatography (eluent: 0-100% hexane solution of ethyl acetate) to afford 1-Boc-3-trifluoromethylpiperazine (200 mg, 0.787 mmol, 90% yield) as a light yellow solid. Mass spectrometry (ES+) analysis: the theoretical value of C10H17F3N2O2 was 254 and the measured value was 155 [M+H]+ - Boc group.
