General procedure for the synthesis of N-(4-(N-(5-methylisoxazol-3-yl)aminosulfonyl)phenyl)acetamide from 3-amino-5-methylisoxazole and p-acetamidobenzenesulfonyl chloride: a mixture of 4-acetamidobenzene-1-sulfonyl chloride (4.27 mmol), 5-methylisoxazol-3-amine (4.49 mmol) and DMAP (0.21 mmol) in an anhydrous The mixture in pyridine (10 mL) was stirred at room temperature for 12 hours. After completion of the reaction, the solvent was evaporated to dryness and the residue was diluted with water and extracted with ethyl acetate. The combined organic layers were washed sequentially with water and 1 M aqueous HCl, dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The resulting solid residue was purified by fast column chromatography using heptane to ethyl acetate (50-100%) gradient elution to afford the target compound N-(4-(N-(5-methylisoxazol-3-yl)aminosulfonyl)phenyl)acetamide. Yield: 59%; ESIMS m/z calculated value C12H13N3O4S [M + H]+, 296.07; measured value 296.06; 1H NMR (400 MHz, (CD3)2SO): δ 11.30 (bs, 1H), 10.35 (bs, 1H), 7.79-7.73 (m, 4H), 6.12 (s, 1H). 2.29 (s, 3H), 2.07 (s, 3H).13C NMR (100 MHz, (CD3)2SO): δ 170.71, 169.57, 158.07, 144.01, 133.36, 128.50, 119.15, 95.84, 24.57, 12.48.
