Methanesulfonyl chloride → 4-Ethyl-N-hexyl-4-(3-methanesulfonylaminophenyl)piperidine

To 4-(3-aminophenyl)-4-ethyl-N-hexylpiperidine (Preparation 64, 50.0 mg, 0.174 mmol) in anhydrous pyridine (4 ml) under nitrogen at 0° C. was added methanesulfonyl chloride (0.2 ml, 1.18 mmol). The solution was stirred at room temperature for 48 h. Ice (5 g) was added and, after 30 min, the reaction mixture was extracted with dichloromethane (10 ml). The organic extract was dried (Na2SO4), filtered and concentrated in vacuo to give the crude product which was purified by silica (5 g) column chromatography, eluting with ethyl acetate:hexane:0.880 ammonia (40:60:1), then ethyl acetate:0.880 ammonia (100:1) and then methanol:ethyl acetate:0.880 ammonia (10:89:1) to give the title compound as an oil (20 mg, 29%).