A solution of N-phenylbenzenesulphonamide (2.34 g) in dry N,N-dimethylformamide (10 cc) is added dropwise to a suspension of sodium hydride (0.24 g, 80% suspension in oil) in N,N-dimethylformamide (50 cc). After 15 minutes' stirring, a solution of 1-(3-chloropropyl)-4-phenyl-1,2,3,6-tetrahydropyridine (2.34 g) in N,N-dimethylformamide (20 cc) is added. The reaction mixture is heated to 140° C. for 1 hour and then cooled and poured into a mixture of water (200 cc) and ethyl acetate (200 cc). The organic phase is washed with water, is dried over magnesium sulphate and is concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a column of silica gel (0.2-0.063-mm particle size, 4-cm diameter, 40-cm height) and eluted with dichloromethane and with a mixture of dichloromethane and ethanol (98-2 and 96-4 by volume), fractions 250-cc being collected. Fractions 5 to 9 are combined and concentrated to dryness under reduced pressure (2.7 kPa). After recrystallization from isopropyl ether (150 cc), N-[3-(4-phenyl-1,2,3,6-tetrahydropyridyl)propyl]-N-phenylbenzenesulphonamide (2.4 g) is obtained, melting at 112° C.
