Acetamidomalonic acid diethyl ester → Diethyl 2-acetamido-2-(5-nitropyridin-2-yl)propanedioate

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Reaction Conditions

Reaction Steps

To a stirred slurry of sodium hydride (46 g, 1 mol, 50% oil dispersion) in dimethylformamide (500 mL, distilled from calcium oxide) was slowly added a solution of diethyl acetamidomalonate (217 g, 1 mol) in dimethylformamide (1200 mL). After the initial reaction, the slurry was heated to 45° C. for 1.5 hours and then 2-chloro-5-nitropyridine (159 g, 1 mol) in DMF (800 mL) was added. The mixture became dark brown during addition of the 2-chloro-5-nitropyridine. The mixture was stirred at 45° C. overnight. After cooling, the mixture was diluted with 1000 mL hydrochloric acid (0.2 N), and then extracted with dichloromethane (3×1200 mL). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the solvent evaporated to give a dark brown oil. The oil was dry-loaded on silica gel and chromatographed on a dry-packed silica gel column. The column was eluted with petroleum ether-ethyl acetate (8:1 and then 5:1). Fractions containing the indicated compound were combined and concentrated to give pale yellow solid. Mp 82-83° C.

Provenance & Evidence