Dimethylformamide → 6-Formyl-4-methoxy-quinoline-3-carboxylic acid methyl ester

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Reaction Steps

A mixture of 6-iodo-4-methoxy-quinoline-3-carboxylic acid methyl ester (example 1d) (1.37 g, 4 mmol), triethylamine (1.4 mL, 10 mmol), diphenylpropylphosphine (dpp, 45 uL, 0.2 mmol) and palladium(II) acetate (45 mg, 0.2 mmol) in dry N,N-dimethylformamide (30 mL) in pressure tube was stirred under carbon monoxide at 75 psi at room temperature for 10 min. After addition of trihexylsilane (2.8 mL, 8 mmol), the mixture was then stirred under carbon monoxide at 75 psi at 80° C. for 3 h. The reaction was allowed to cool to 25° C. and then extracted with methylene chloride (2×100 mL). The combined organic layers were successively washed with a saturated aqueous sodium bicarbonate solution (3×50 mL) and water (3×50 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70-230 mesh, 0%-40% ethyl acetate in hexanes in 30 min) afforded 6-formyl-4-methoxy-quinoline-3-carboxylic acid methyl ester (0.48 g, 50%) as a white solid.

Provenance & Evidence