Trifluoroacetic acid → 2-(5-Fluoro-2-methyl-phenyl)-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a mixture of 2-(5-fluoro-2-methyl-phenyl)-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethylester (3.78 g, 10.6 mmol) and triethylsilane (10 mL) at 25° C. was added trifluoroacetic acid (2 mL) dropwise. The resulting mixture was stirred at 25° C. for 1 h. Then the reaction mixture was concentrated in vacuo and the residue was extracted with ethyl acetate (2×50 mL), washed with saturated aqueous sodium bicarbonate solution (2×20 mL), dried over anhydrous sodium sulfate and concentrated in vacuo. Purification on flash silica gel chromatography (silica gel from QingDao, 200-300 mesh, glass column from Shanghai SD company) (10% ethyl acetate/hexanes) to afford 2-(5-fluoro-2-methyl-phenyl)-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester (0.70 g, 19%) as a white solid: LC/MS m/e calcd for C21H24FNO2 (M+H)+: 342.4, observed: 342.3.

Provenance & Evidence