0.37 g of 1-[2-(4-Fluorophenyl)-2-(4-methylpiperazino)ethyl]piperazine obtained in Example 2 (4) was dissolved in 4.0 ml of dimethylformamide, and 0.19 g of N-ethyldiisopropylamine and 0.31 g of 4-(6-fluoro-1,2-benzisoxazol-3-yl)butyl chloride were added, followed by stirring at 120° C. for 3 hours. The reaction solution was cooled to room temperature, diluted with ethyl acetate and washed with water and a saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous sodium sulfate. After removal of the drying agent by filtration, the filtrate was concentrated under reduced pressure. The residue was purified by a silica gel column chromatography (Chromatorex NH, hexane:ethyl acetate=1:1) to give 0.22 g of 1-[2-(4-fluorophenyl)-2-(4-methylpiperazino)ethyl]-4-[4-(6-fluoro-1,2-benzisoxazol-3-yl)butyl]piperazine as an oil.
