C[O:2][C:3](=[O:19])[CH:4]([C:11]1[CH:16]=[CH:15][CH:14]=[C:13]([O:17][CH3:18])[CH:12]=1)[CH2:5][CH:6]1[CH2:10][CH2:9][CH2:8][CH2:7]1.[OH-].[Na+].O>O1CCCC1.O.CO>[CH:6]1([CH2:5][CH:4]([C:11]2[CH:16]=[CH:15][CH:14]=[C:13]([O:17][CH3:18])[CH:12]=2)[C:3]([OH:19])=[O:2])[CH2:10][CH2:9][CH2:8][CH2:7]1A solution of 3-cyclopentyl-2-(3-methoxy-phenyl)-propionic acid methyl ester (1.39 g, 5.29 mmol) in tetrahydrofuran/water/methanol (13.2 mL, 3:1:1) at 25° C. was treated with a 2N aqueous sodium hydroxide solution (3.97 mL, 7.94 mmol). The reaction was stirred at 25° C. for 48 h. At this time, the reaction mixture was poured into water (50 mL) and extracted with chloroform (3×25 mL). The aqueous layer was acidified to pH=1 with a 1N aqueous hydrochloric acid solution. The aqueous layer was extracted with a solution of chloroform/methanol (9:1). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 70/30 hexanes/ethyl acetate with glacial acetic acid) afforded 3-cyclopentyl-2-(3-methoxy-phenyl)-propionic acid (1.05 g, 79.8%) as a clear wax: EI-HRMS m/e calcd for C15H20O3 (M+) 248.1412, found 248.1409.
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