Reaction Steps
A mixture of 0.450 mmol of 3-{7-[2-(3-fluoropropoxy)-3,5-diisopropylphenyl]-benzo[b]furan-2-yl}-but-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. 3-{7-[2-(3-Fluoropropoxy)-3,5-diisopropylphenyl]-benzo[b]furan-2-yl}-but-2-enoic acid was isolated as a white solid. 1H-NMR (CDCl3),: 7.58 (d, J=6.7 Hz, 1H, Ar—H), 7.56 (d, J=6.2 Hz, 1H, Ar—H), 7.29 (t, J=7.6 Hz, 1H, Ar—H), 7.28 (d, J=2.2 Hz, 1H, Ar—H), 7.17 (d, J=2.1 Hz, 1H, Ar—H), 7.11 (s, 1H, furan-H), 6.59 (s, 1H, C═C—H), 4.25 (dt, J=47.1 Hz, J=6.1 Hz, 2H, O—CH2—CH2—CH2F), 3.46 (t, J=5.9 Hz, 2H, O—CH2—CH2—CH2F), 3.38 (m, 1H, CH3—CH—CH3), 2.95 (m, 1H, CH3—CH—CH3), 2.56 (s, 3H, C═C—CH3), 1.70 (m, 2H, O—CH2—CH2—CH2F), 1.32 (d, J=5.7 Hz, 6H, CH3—CH—CH3), 1.30 (d, J=6.6 Hz, 6H, CH3—CH—CH3).
