To a solution of 1-benzylpiperidin-4-one (26.42 mmol, 1.0 equiv.) and acetic acid (26.42 mmol, 1.0 equiv.) in methanol (10 ml) were added water (600 ml), N-cyclopropyl piperazine (29.06 mmol, 1.1 equiv.), and potassium cyanide (26.42 mmol, 1.0 equiv.). The resulting reaction mixture was stirred at room temperature for 1 h by which time a solid had separated. The solid was collected by filtration, washed with water and dried to obtain the desired product which was used in the next step without further purification. Yield: 53%.
