100 g (0.608 mol) of 2-(trifluoromethyl)aniline, 131 g (0.639 mol) of 85% sodium hydrosulfite, and 20.9 g (0.0608 mol) of tetrabutylammonium hydrogen sulfate were charged to a mixed solution of 1500 ml of ethyl acetate and 1500 ml of water, and 53.9 g (0.639 mol) of sodium hydrogen carbonate was added thereto. 198 g (0.669 mol) of heptafluoroisopropyl iodide was added dropwise thereto at room temperature, followed by stirring at room temperature for 6 hours. After the liquid separation, the solvent of the organic layer was evaporated under reduced pressure, and 500 ml of ethyl acetate was charged thereto. 160 g (0.608 mol) of a 4 M hydrogen chloride/ethyl acetate solution was added dropwise thereto, followed by stirring at room temperature for 30 minutes, and then stirring at 5° C. for 1 hour. After the filtration, the filtrate was washed with water and a saturated aqueous sodium hydrogen carbonate in this order, and then dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (eluent solvent; hexane:ethyl acetate=10:1) to prepare 60.0 g (yield 30%) of a target compound.
