To a stirred suspension of N-[2-(2-amino-benzoyl)-5-chloro-pyridin-3-yl]-4-chloro-N-methoxymethyl-3-trifluoromethyl-benzenesulfonamide in pyridine (1 mL) was added methanesulfonyl chloride (26 mg, 0.226 mmol). After 2 h the reaction mixture was poured into 1 M HCl and the aqueous portions were subsequently extracted with EtOAc. The combined extracts were dried and concentrated under reduced pressure. The resulting residue was dissolved in THF (5 mL), treated with TBAF (1 M in THF, 200 μL, 0.200 mmol), and then stirred at room temperature for 3-4 h. The reaction mixture was subsequently poured into 1 M HCl and the aqueous layer was extracted with EtOAc. The combined organic extracts were dried (Na2SO4), filtered, and concentrated under reduced pressure to provide 4-chloro-N-[5-chloro-2-(2-methanesulfonylamino-benzoyl)-pyridin-3-yl]-N-methoxymethyl-3-trifluoromethyl-benzenesulfonamide. MS m/z: 634.0 (M+Na).
