反应详情

温度

80 °C

Into a 50-mL round bottomed flask was added ethanol (4 mL) under argon, followed by sodium (0.121 g, 5.25 mmol). The mixture was stirred at room temperature for 15 min, during which a solution of ethyl 3-((3-ethoxy-3-oxopropyl)(methyl)amino)-3-oxopropanoate (1.17 g, 4.77 mmol) in ethanol (5 mL) was added. The resulting clear, colorless mixture was heated at 80° C. for 1 h, during which LC-MS indicated completion of reaction and a clean conversion to the desired ethyl 1-methyl-2,4-dioxopiperidine-3-carboxylate intermediate. Upon cooling to room temperature, the reaction was diluted with Et2O, resulting in the formation of a white precipitate (desired product). The white precipitate was collected via filtration, taken up in 5% aqueous HCl solution (8 mL), and refluxed for 1 h. The cooled mixture was extracted with CH2Cl2 (5×) and the combined organic extracts were dried (MgSO4), filtered, and concentrated in vacuo. Flash column chromatography (20% EtOAc/Hexanes to 100% EtOAc) afforded 1-methylpiperidine-2,4-dione as a viscous milky oil. [M+1]=128.1.

1. additionwas added
2. customcompletion of reaction
3. temperatureUpon cooling to room temperature