C([O:3][C:4](=[O:33])[C:5]([F:32])=[CH:6][C:7]1[S:11][C:10]2[CH:12]=[CH:13][CH:14]=[C:15]([C:16]3[CH:21]=[C:20]([CH:22]([CH3:24])[CH3:23])[CH:19]=[C:18]([CH:25]([CH3:27])[CH3:26])[C:17]=3[O:28][CH2:29][CH2:30][CH3:31])[C:9]=2[CH:8]=1)C.C1COCC1.[Li+].[OH-]>CO>[F:32]/[C:5](=[CH:6]/[C:7]1[S:11][C:10]2[CH:12]=[CH:13][CH:14]=[C:15]([C:16]3[CH:21]=[C:20]([CH:22]([CH3:23])[CH3:24])[CH:19]=[C:18]([CH:25]([CH3:26])[CH3:27])[C:17]=3[O:28][CH2:29][CH2:30][CH3:31])[C:9]=2[CH:8]=1)/[C:4]([OH:33])=[O:3]A mixture of 0.450 mmol of 2-fluoro-3-[4-(2-n-propoxy-3,5-di-iso-propylphenyl)-benzo[b]thien-2-yl]-prop-2-enoic acid ethyl ester, 3 mL of THF, 3 mL of methanol and 1 mL of LiOH (2N aqueous) was refluxed for 2 hours. After cooling at room temperature, the mixture was acidified to pH=2 and extracted with ethyl acetate. The organic layer was dried over MgSO4 and after evaporation of the solvents, the crude acid was recrystallized from acetonitrile. (E)-2-Fluoro-3-[4-(2-n-propoxy-3,5-di-iso-propylphenyl)-benzo[b]thien-2-yl]-prop-2-enoic acid was isolated as a white solid. 1H-NMR (CDCl3), δ: 7.83 (d, J=7.7 Hz, 1H), 7.49 (broad s, 1H), 7.46 (s, 1H), 7.42 (t, J=7.0 Hz, 2H), 7.18 (d, J=2.1 Hz, 1H), 7.00 (d, J=2.1 Hz, 1H), 3.42 (dt, J=13.7, 6.8 Hz, 1H), 3.32 (m, 1H), 3.19 (m, 1H), 2.92 (dt, J=13.8, 6.9 Hz, 1H), 1.29 (m, 14H), 1.22 (m, 2H), 0.45 (t, J=7.3 Hz, 3H).
Loading…