3,3-dimethylpyridine-2,4(1H,3H)-dione → 6-(3,5-Difluorophenyl)-3,3-dimethylpiperidine-2,4-dione

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Reaction Steps

To a solution of 3,3-dimethylpyridine-2,4(1H,3H)-dione (978 mg, 7.03 mmol) [U.S. Pat. No. 2,525,231] in benzene (10 mL) was added 3,5-difluorophenylmagnesium bromide (50 mL of a 0.5 M solution in THF, 25 mmol) and the resulting mixture was heated to reflux for 1.5 h. The mixture was cooled, quenched with 1 N aqueous HCl (10 mL), made basic with saturated NaHCO3 solution (100 mL) and extracted with EtOAc (2×150 mL). The combined organic layers were washed with H2O (50 mL), then brine (50 mL), and dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of hexane:EtOAc—100:0 to 60:40, to give the title compound. MS: m/z=254 (M+1).

Provenance & Evidence