Water → 2-(5-Bromo-pyridin-3-yl)-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of 4-[(5-bromo-pyridin-3-ylmethylene)-amino]-benzoic acid ethyl ester (16.3 g, 49 mmol) and ytterbium(III) triflate hydrate (3.1 g, 49 mmol) in dry tetrahydrofuran (100 mL) at 25° C. was added isobutyraldehyde (4.98 mL, 55 mmol) and water (0.89 mL, 49 mmol) dropwise. The reaction mixture was stirred at 25° C. for 12 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-(5-bromo-pyridin-3-yl)-4-hydroxy-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester (16 g, 80%) as a light yellow oil which was used for next step without further purification: LC/MS m/e calcd for C19H21BrN2O3 (M+H)+: 406.29, observed: 405.1.

Provenance & Evidence