ethyl 6,6-dimethyl-2,4-dioxopiperidine-3-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl 6,6-dimethyl-2,4-dioxopiperidine-3-carboxylate (0.69 g, 3.23 mmol) was dissolved in acetonitrile containing 1% of water (15 mL) and the resulting solution was refluxed for 2 hours. After evaporating to dryness, the crude material was suspended in isopropyl ether, kept under vigorous stirring and filtered to give the title compound (387 mg, Y=85%) as a light brown solid. the resulting solution was refluxed for 2 hours After evaporating to dryness filtered

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of sodium ethoxide, obtained from sodium metal (0.122 g, 5.55 mmol) in anhydrous ethanol (7 mL), a solution of ethyl 3-[(3-ethoxy-3-oxopropanoyl)amino]-3-methylbutanoate (1.2 g, 4.62 mmol) in dry toluene (7 mL) was added dropwise at room temperature, under stirring. The reaction mixture was heated at 80° C. for 2 hours then it was concentrated to reduced volume and the residue was dissolved in toluene (15 mL). The organic phase was extracted with water (40 mL), the aqueous phase was acidified to pH 2-3 with 1 N HCl and extracted with ethyl acetate (4×50 mL). The organic phase was washed with brine, dried over anhydrous sodium sulphate and concentrated to give ethyl 6,6-dimethyl-2,4-dioxopiperidine-3-carboxylate as a yellow solid (0.7 g, Y=71%) which was used for the next step without further purification. it was concentrated to reduced volume the residue was dissolved in toluene (15 mL) The organic phase was extracted with water (40 mL) extracted with ethyl acetate (4×50 mL) The organic phase was washed with brine dried over anhydrous sodium sulphate concentrated