Hydrochloric Acid → Ethyl 4-[5-(4-trifluoromethylphenyl)-2-thienyl]benzoate

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Reaction Steps

To a solution (7 ml) of 2-(4-trifluoromethylphenyl) thiophene (1.71 g) in tetrahydrofuran was added dropwise n-butyl lithium (1.6 M solution in hexane, 5.00 ml) under an argon atmosphere at −78° C. This mixed solution was heated to room temperature, and a solution (14 ml) of zinc chloride (1.09 g) in tetrahydrofuran was added. This mixture was stirred for 1 hr., and ethyl 4-iodobenzoate (1.16 ml) and tetrakis(triphenylphosphine)palladium (0.202 g) were added. This mixture was stirred overnight under an argon atmosphere and poured into 0.5 M hydrochloric acid. The mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated. Ethanol (200 ml) was added to the residue, and the mixture was heated under reflux for 10 min. Insoluble materials were filtered off, and the filtrate was concentrated to give ethyl 4-[5-(4-trifluoromethylphenyl)-2-thienyl]benzoate (1.19 g, yield 45%) as a yellow crystalline powder. melting point: 203–204° C.

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