Into a solution of 91.9 g of 3-{1-[3-(4-cyanophenoxy)propyl]-4-piperidinyl}propyl methanesulfonate in 460 mL of dimethylsulfoxide, 66.9 g of potassium carbonate and 28.8 g of 4-cyanophenol were added at room temperature, and the solution was stirred at 60° C. for 2 hours. To the reaction mixture, after being cooled down to room temperature, 640 mL of water was dropped over 20 min, and then the mixture was stirred at room temperature for 35 min, and under water cooling for 30 min. The solid matter was collected by filtration, and washed twice with 180 mL of water and then 360 mL of 2-propanol to obtain 90.0 g of 4-(3-{4-[3-(4-cyanophenoxy)propyl]-1-piperidinyl}propoxy)benzonitrile as a white solid.
