Short-RInChIKey=SA-FUHFF-UHFFFADPSC-URBKDTWJYJ-UHFFFADPSC-NUHFF-NUHFF-NUHFF-ZZZ

1,2-Phenylenediamine (5.00 g, 46.2 mmol, 1.00 equiv) was dissolved in methylene chloride (150 mL) then pyridine (14.6 g, 14.9 mL, 185 mmol, 4.00 equiv) was added at 0 °C. 4-Methylbenzenesulfonyl chloride (18.5 g, 97.1 mmol, 2.10 equiv) in methylene chloride (100 mL) was added dropwise to the solution at 0 °C. The solution was stirred for 12 h at 21 °C. Brine (500 mL) was added and the aqueous phase was extracted 3x with methylene chloride (500 mL). The organic layers were combined, dried over Na2SO4, filtered and the solvent was removed under reduced pressure.