Aniline → N-benzene sulfonyl phenyl cyanamide

To a 3 liter 3-necked flask equipped with a stirrer, addition funnel, thermometer, and drying tube was charged 93.1 g (1.0 mole) of aniline, 111 g (1.1 moles) of triethylene diamine and 250 ml. of tetrahydrofuran. To this reaction mixture was added dropwise a solution of 176.6 g (1 mole) of benzenesulfonyl chloride in 300 ml. of tetrahydrofuran. The reaction mixture was stirred at room temperature for 2.5 hours and was then filtered. To the filtrate was added 111 g of triethylene diamine and this solution was added dropwise to a solution of 87 g (1.41 moles) of cyanogen chloride in 100 ml. of THF which was maintained at -5° C. with cooling. After this addition was complete the stirred reaction mixture was allowed to return to room temperature over a 161/2 hour period. The reaction mixture was filtered and the filament was added to water to precipitate the product. The product was recrystallized from aqueous methanol to yield 218 g (84.7%) of N-benzene sulfonyl phenyl cyanamide, m.p. 65°-66° C.