A suspension of 32.1 g (0.1 m) of 3-[[(4-nitrophenyl)sulfonyl]-amino]-benzamide and 208 g (0.1 m) of phosphorous pentachloride in a mixture of 300 ml of carbon tetrachloride and 100 ml of nitromethane was stirred and heated for 90 min. The resulting solution was cooled to 20° and 4.7 g (0.1 m) of 97% formic acid added. The reaction was stirred overnight, then the product collected by filtration, washed with carbon tetrachloride and air-dried to give 36.7 g, melts 133°-134°, solidifies 138°, melts 188°-193°.
