A mixture of 6.00 g (0.035 mole) of 1-(3-aminopropyl)-4-methylpiperazine and 6.97 g (0.043 mole) of 1,1'-carbonyldiimidazole in 400 ml of tetrahydrofuran was stirred at room temperature for 1 hr. A solution of 8.17 g (0.036 mole) of N-(2-phenylsulfonylethyl)-2-propanamine in 100 ml of tetrahydrofuran was added, and the mixture was refluxed for 16 hr. The solvent was removed in vacuo and the residue was partitioned between methylene chloride and water. The solution was dried over magnesium sulfate, and the solvent was removed in vacuo to give an oil. The oil was dissolved in methanol; a solution of two equivalents of maleic acid in methanol was added, and a white solid precipitated. This was collected to give 15.48 g (68.8%) of white crystalline solid; m.p. 162°-163° C. with decomposition.
