To a stirred solution of the above alcohol (1.01 g, 0.004 mol) and triethylamine (1.02 g, 0.010 mol) in toluene (25 ml) at 0° C., methanesulfonyl chloride (0.6 ml, 0.0077 mol) was added dropwise over 10 minutes. The resulting mixture, was stirred at 0° C. for 1.5 h. Water (50 ml) was added and the phases were separated. The aqueous phase was extracted with toluene (50 ml), and the combined organic phases were washed with brine (2×50 ml), dried (MgSO4) and concentrated in vacuo. The crude mesylate was mixed with 4-(4-chlorophenyl)piperidin-4-ol (0.81 g, 0.004 mol) and potassium carbonate (1.08 g, 0.008 mol) in acetonitrile (9 ml) and heated at reflux temperature for 6 h. The reaction mixture was left stirring at room temperature for 2 days. Water (50 ml) was added and the mixture was extracted with ethyl acetate (3×15 ml), washed with brine (2×20 ml), dried (MgSO4) and concentrated in vacuo. Water (50 ml) was added and the mixture was acidified by addition of concentrated hydrochloric acid (3 ml). The aqueous solution was extracted with dichloromethane (2×20 ml), washed with brine (2×20 ml), dried (MgSO4) and concentrated in vacuo. The resulting oil was dissolved in a mixture of ethyl acetate (15 ml) and methanol (2 ml). Heptane was added in small portions, just until the solution turned slightly turbid. After 4 h, crystals were filtered off, washed with heptane and dried, affording 1.1 g (61%) of the title compound as a solid.
