A mixture of 40.94 g (0.20 mole) of [(2-chloroethyl)sulfonyl]benzene, 27.85 g (0.217 mole) of N-(2-aminoethyl)piperidine and 28.0 g (0.277 mole) of triethylamine in 800 ml of acetonitrile was stirred at room temperature overnight. The solvent was removed in vacuo, and the residue was partitioned between methylene chloride and dilute sodium hydroxide. The methylene chloride solution was dried over magnesium sulfate, and the solvent was removed in vacuo. The residue was dissolved in methanol, a solution of 2 equivalents of maleic acid in methanol was added, and the product crystallized from the solution at room temperatue to give 64.35 g (60.78%) of title compound as a white crystalline solid, mp 154°-155.5° C.
