Triethylsilane → 2-(3-Bromo-phenyl)-8-fluoro-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-7-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

To a stirred mixture solution of 2-(3-bromo-phenyl)-8-fluoro-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-7-carboxylic acid methyl ester (63.0 g, 154 mmol) and triethylsilane (60 mL) at 25° C. was added trifluoroacetic acid (30 mL) dropwise. The resulting mixture solution was stirred at 25° C. for 3 hours. Then the reaction mixture was concentrated in vacuo and the residue was extracted with ethyl acetate (2×200 mL), washed with saturated aqueous sodium bicarbonate solution (4×100 mL), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was triturated with methanol. The resulting precipitate was collected, dried in vacuo to afford 2-(3-bromo-phenyl)-8-fluoro-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-7-carboxylic acid methyl ester (30.2 g, 50%) as a yellow oil: LC/MS m/e calcd for C19H19BrFNO2 (M+H)+: 393.27, observed: 392.0 & 394.0. A mixture of 2-(3-bromo-phenyl)-8-fluoro-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-7-carboxylic acid methyl ester (6.0 g, 15.3 mmol), morpholine (13.3 mL, 153 mmol), copper(I) iodide (874 mg, 4.6 mmol), N,N-dimethylglycine hydrochloride (1.3 g, 9.2 mmol) and potassium carbonate (8.5 g, 61.2 mmol) in dimethyl sulfoxide (15 mL) was stirred at 120° C. for 16 h. Then the reaction mixture cooled to room temperature. The reaction mixture was extracted with ethyl acetate (2×150 mL), washed with water (2×50 mL) and saturated aqueous ammonium chloride solution (2×50 mL), dried over anhydrous sodium sulfate and then concentrated in vacuo to afford 8-fluoro-3,3-dimethyl-2-(3-morpholin-4-yl-phenyl)-1,2,3,4-tetrahydro-quinoline-7-carboxylic acid methyl ester (4.8 g, 80%) as a white solid which was used for next step without further purification: LC/MS m/e calcd for C23H27FN2O3 (M+H)+: 399.48, observed: 399.1.

Provenance & Evidence