Lithium Hydroxide → 3-[7-(2-Ethoxy-3,5-diisopropylphenyl)-benzo[b]furan-2-yl]-but-2-enoic acid

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Reaction Steps

A mixture of 0.450 mmol of 3-[7-(2-ethoxy-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-Ethoxy-3,5-diisopropylphenyl)-benzo[b]furan-2-yl]-but-2-enoic acid was isolated as a white solid. 1H-NMR (CDCl3), δ: 7.65 (d, J=7.5 Hz, 1H, Ar—H), 7.56 (d, J=7.7 Hz, 1H, Ar—H), 7.33 (d, J=2.0 Hz, 1H, Ar—H), 7.29 (t, J=7.6 Hz, 1H, Ar—H), 7.16 (d, J=2.0 Hz, 1H, Ar—H), 7.11 (s, 1H, furan-H), 6.60 (s, 1H, C═C—H), 3.43 (m, 3H, CH3—CH—CH3, O—CH2—CH3), 2.95 (m, 1H, CH3—CH—CH3), 2.57 (s, 3H, C═C—CH3), 1.31 (d, J=6.9 Hz, 12H, CH3—CH—CH3), 0.97 (t, J=7.0 Hz, 3H, O—CH2—CH3).

Provenance & Evidence