[F:1][C:2]1[CH:3]=[C:4]([CH:14]([CH3:20])[C:15]([O:17]CC)=[O:16])[CH:5]=[CH:6][C:7]=1[CH2:8][NH:9][S:10]([CH3:13])(=[O:12])=[O:11].[OH-].[Li+]>O1CCCC1.O>[F:1][C:2]1[CH:3]=[C:4]([CH:14]([CH3:20])[C:15]([OH:17])=[O:16])[CH:5]=[CH:6][C:7]=1[CH2:8][NH:9][S:10]([CH3:13])(=[O:11])=[O:12]The ethyl 2-(3-fluoro-4-(methylsulfonamidomethyl)phenyl)propanoate (12.5 g, 40.4 mmol) was dissolved in tetrahydrofuran-water mixture (120 mL, 2:1), lithium hydroxide (2.8 g, 121.1 mmol) was added and refluxing carried out for 12 h. After evaporation of the organic solvent under reduced pressure, the reaction mixture was extracted with diethyl ether (2×100 mL). The aqueous layer was acidified using 1 N HCl solution to pH=2 and extracted with dichloromethane (3×250 mL). The combined organic layer was dried over magnesium sulfate and concentrated under reduced pressure to afford 2-(3-fluoro-4-(methylsulfonamido-methyl)phenyl)propanoic acid (9.56 g, 86%).
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