Water → 2-(3-Bromo-phenyl)-6-chloro-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-8-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

To a stirred mixture solution of 2-[(3-bromo-benzylidene)-amino]-5-chloro-benzoic acid methyl ester (39.8 g, 113.2 mmol) and ytterbium(III) triflate hydrate (10.5 g, 16.9 mmol) in dry tetrahydrofuran (100 mL) at 25° C. was added isobutyraldehyde (10.4 mL, 113.2 mmol) and water (2.1 mL, 113.2 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-chloro-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-8-carboxylic acid methyl ester (48 g, quant.) as a light yellow oil which was used for next step without further purification: LC/MS m/e calcd for C19H19BrClNO3 (M+H)+: 425.73, observed: 405.9 & 407.9.

Provenance & Evidence