Water → 2-(3-Bromo-phenyl)-6-fluoro-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-5-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture solution of 5-[(3-bromo-benzylidene)-amino]-2-fluoro-benzoic acid methyl ester (51.7 g, 153.8 mmol) and ytterbium(III) triflate hydrate (14.3 g, 23.1 mmol) in dry tetrahydrofuran (100 mL) at 25° C. was added isobutyraldehyde (14 mL, 153.8 mmol) and water (2.8 mL, 153.8 mmol) dropwise. The reaction mixture was stirred at 25° C. for 16 h. Then the reaction mixture was concentrated in vacuo and the residue was extracted with ethyl acetate (2×200 mL), washed with brine, dried over anhydrous sodium sulfate and concentrated in vacuo to afford 2-(3-bromo-phenyl)-6-fluoro-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-5-carboxylic acid methyl ester (63.0 g, quant.) as a light yellow oil which was used for next step without further purification: LC/MS m/e calcd for C19H19BrFNO3 (M+H)+: 409.27, observed: 390.0 & 392.0.

Provenance & Evidence