b) 6-Bromo-N-(tert-butyl)pyridine-2-sulfonamide (478 mg, 1.63 mmol) was dissolved in trifluoroacetic acid (TFA, 2 mL), and the reaction mixture was stirred for 3 hours at 60 °C. After completion of the reaction, TFA was evaporated under reduced pressure and the residue was treated with a solvent mixture of petroleum ether and ethyl ether (Et2O) to precipitate a brown solid. The solid was collected by filtration and ground three times with ether to give the final white solid product 6-bromopyridine-2-sulfonamide (125 mg, 32% yield). The product was characterized by 1H NMR (DMSO-d6, ppm): 7.98 (t, J=7.5 Hz, 1H), 7.91 (dd, J=7.5 and 1.2 Hz, 1H), 7.87 (dd, J=7.5 and 0.9 Hz, 1H).
