Sodium hydride → tert-Butyl 2-[4-(5-chloro-2-cyanophenyl)-5-methoxy-2-oxopyridin-1(2H)-yl]-4-methoxybutanoate

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Reaction Steps

A little at a time, 405 mg (10.1 mmol) of sodium hydride (60% in mineral oil) were added to a suspension of 2.4 g (9.2 mmol) of 4-chloro-2-(5-methoxy-2-oxo-1,2-dihydropyridin-4-yl)benzonitrile in 70 ml of tetrahydrofuran, and the mixture was stirred at RT for another 1 h. 4.45 g (13.8 mmol) of tert-butyl 4-methoxy-2-{[(trifluoromethyl)sulphonyl]oxy}butanoate (racemate) as a solution in 20 ml of THF were quickly added dropwise to the resulting reaction solution, and after the addition had ended the mixture was stirred at RT for another 1.5 h. The reaction was terminated by addition of 150 ml of saturated aqueous ammonium chloride solution and 150 ml of methyl tert-butyl ether. The phases were separated and the aqueous phase was extracted three times with 130 ml of methyl tert-butyl ether. The combined organic phases were dried over magnesium sulphate and filtered, and the solvent was removed under reduced pressure. The crude product was purified by flash chromatography (120 g silica cartridge, 85 ml/min, cyclohexane/ethyl acetate gradient), giving the title compound. Yield: 1.73 g (43% of theory)

Provenance & Evidence