Potassium Carbonate → Ethyl 4-oxobutanoate

Beteiligte Stoffe

Reaktionsschritte

A mixture of 4-[4-(3-chloropropoxy)-3,5-difluorophenyl]-4-oxo-butyric acid ethyl ester (5 g, 14.9 mmol), K2CO3 (7.2 g, 52.1 mmol), NaI (220 mg, 1.4 mmol), and Benzenesulfonate; (R)-methylpyrrolidinium (8 g, 33 mmol) in CH3CN (110 mL) was heated under argon at 80° C. for 36 h. The reaction was concentrated and partitioned between saturated aqueous sodium bicarbonate solution and methylene chloride. The aqueous layer was extracted twice with methylene chloride and the combined organics was washed with brine, dried (Na2SO4), filtered, and concentrated to provide a crude material (96% purity). The crude material was purified by ISCO (80 g silica gel column) chromatography using 2% to 9% methanol in methylene chloride to 10% methanol containing 0.1% ammonium hydroxide in methylene chloride. The isolated material was dissolved in methylene chloride and washed with saturated aqueous sodium bicarbonate solution, brine, dried (Na2SO4), filtered, and concentrated. The isolated material was crystallized with a mixture of methylene chloride, ether and hexane to obtain 4-{3,5-difluoro-4-[3-(R)-2-methyl-pyrrolidin-1-yl)-propoxy]-phenyl}-4-oxo-butyric acid ethyl ester (3.97 g, 70%, 99% purity), MS m/z=384 (M+H).

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