A mixture of 4-[2-methyl-4-(2,4,6-trimethyl-phenylamino)-pyrimidine-5-sulfonyl]-phenol (46 mg, 0.12 mmol), prepared as described in Example 2, acetic anhydride (0.023 mL, 0.24 mmol), triethylamine (0.05 mL, 0.36 mmol) and CH2Cl2 (4 mL) was stirred at room temperature under N2 for 4 h. The reaction mixture was treated with saturated sodium bicarbonate, and extracted (3×) with CH2Cl2. The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by chromatography on silica gel (50:50 hexanes/EtOAc) to provide the target compound (47 mg, 92%) as a white solid: mp 142–144° C.; 1H NMR (300 MHz, CDCl3) δ 8.76 (s, 1H), 8.23 (br s, 1H), 7.99 (d, J=8.7 Hz, 2H), 7.29 (d, J=8.7 Hz, 2H), 6.92 (s, 2H), 2.40 (s, 3H), 2.33 (s, 3H), 2.31 (s, 3H), 2.01 (s, 6H); APCI MS m/z 426 [(M+H)+, calcd for C22H24N3O4S, 426.1].
