360 mg of 5-{4-(aminosulfonyl)phenyl}-2,2-dimethyl-4-(3-fluorophenyl)-3(2H)-furanone (Example 129) in 30 ml in dichloromethane was reacted with 0.8 ml acetic anhydride in the presence of 0.5 ml triethylamine and 50 mg of 4-(N,N-dimethylamino)pyridine at room temperature for 12 hours. The reaction mixture was concentrated in vacuo, which was followed by extraction with 30 ml water and dichloromethane (30 ml×3). The organic layer was concentrated under reduced pressure and then was purified by column chromatography (hexane/ethylacetate 2:1) to afford 397 mg of 5-[4-{(acetylamino)sulfonyl}phenyl]-2,2-dimethyl-4-(3-fluoro-phenyl)-3(2H)-furanone as a solid. mp: 178-179° C. NMR: δ1.57 (s, 6H), 2.08 (s, 3H), 7.05 (m, 3H), 7.34 (m, 1H), 7.82 (d, J=8.4 Hz, 2H), 8.05 (d, J=8.4 Hz, 2H), 8.20 (br s, 1H). IR (cm−1): 3238, 3198, 1431, 1261, 1159.
