Lithium Hydroxide → (E)-2-Fluoro-3-[4-(2-n-propoxy-3,5-di-iso-propylphenyl)-benzo[b]thien-2-yl]-prop-2-enoic acid

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Reaction Steps

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).

Provenance & Evidence