Lithium Hydroxide → 3-{4-[2-(2,2,2-Trifluoroethoxy)-3-tert-butyl-5-methylphenyl]benzo[b]thien-2-yl}but-2-enoic acid

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Reaction Steps

A mixture of 198 mg (0.41 mmol) of 3-{4-[2-(2,2,2-trifluoroethoxy)-3-tert-butyl-5-methylphenyl]benzo[b]thien-2-yl}but-2-enoic acid ethyl ester disolved in 4 mL of methanol, 5 mL of THF and 1 mL of a 2N aqueous solution of LiOH was heated to reflux for 2 hours. After cooling at room temperature and acidic work-up, the crude acid was purified using preparative HPLC (kromosil column, eluent: 8/92 water/methanol+0.1% TFA). Collection of the desired fractions, evaporation of the solvents and recrystallization from acetonitrile affords 110 mg (0.23 mmol, yield: 58%) of 3-{4-[2-(2,2,2-trifluoroethoxy)-3-tert-butyl-5-methylphenyl]benzo[b]thien-2-yl}but-2-enoic acid as a white solid. 1H NMR (400 MHz, CDCl3) d: 7.80 (d, J=8.2 Hz, 1H), 7.43 (t, J=7.7 Hz, 1H), 7.40 (s, 1H), 7.38 (d, J=8.2 Hz, 1H), 7.24 (d, J=1.9 Hz, 1H), 7.06 (d, J=1.9 Hz, 1H), 6.32 (s, 1H), 3.61 (m, 1H), 3.58 (m, 1H), 2.58 (s, 3H), 2.37 (s, 3H), 1.46 (s, 9H).

Provenance & Evidence