A mixture of 60.24 g (0.350 mole) of [(2-chloroethyl)thio]benzene, 84 g (0.72 mole) of N,N-diethylethylenediamine, and 80.0 g (0.75 mole) of sodium carbonate in 1.5 liters of acetonitrile was refluxed for 16 hr. 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 sodium sulfate, and the solvent was removed in vacuo to give an oil. This was dissolved in 800 ml of methanol. A solution of approximately 2 equivalents of maleic acid in methanol was added followed by the addition of anhydrous diethyl ether until the solution became slightly cloudy. A white solid precipitated at -5° C. to give 73.15 g (43.2%) of title compound, a white crystalline solid, mp 131°-133° C.
