1-methylpiperidine-2,3-dione

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

Procedure: To a solution of ethynylmagnesium bromide (0.5M in tetrahydrofuran, 4 mL, 2 mmol) maintained under nitrogen at −20° C. was added a solution of 1-methylpiperidine-2,3-dione (220 mg, 0.87 mmol) in tetrahydrofuran (3 mL) dropwise with stirring within 1 min. The reaction mixture was stirred for 2 hr at room temperature and then quenched by the addition of saturated ammonium chloride solution (1 mL). The mixture was diluted with DCM (50 mL), dried over anhydrous sodium sulfate and concentrated under vacuum. The crude residue was purified on a silica gel column, elution with ethyl acetate/petroleum ether (0:1-1:0) afforded the title compound (40 mg, 30%) as a brown oil: 1H NMR (400 MHz, CDCl3) delta 4.23 (s, 1H), 3.35-3.30 (m, 2H), 2.95 (s, 3H), 2.47 (s, 1H), 2.35-2.16 (m, 2H), 1.97-1.90 (m, 2H). LC-MS m/z=+154 [M+H]+. The reaction mixture was stirred for 2 hr at room temperature quenched by the addition of saturated ammonium chloride solution (1 mL) The mixture was diluted with DCM (50 mL) dried over anhydrous sodium sulfate concentrated under vacuum The crude residue was purified on a silica gel column, elution with ethyl acetate/petroleum ether (0:1-1:0)

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

Procedure: To a solution of 3-hydroxy-1-methylpiperidin-2-one (1 g, 7.59 mmol) in acetone (50 mL) was added Jones-reagent (2 mL) dropwise at room temperature. The resulting solution was stirred for 10 min at room temperature. The solid material was removed by filtration. The filtrate was concentrated in vacuo at 30-40° C. The residue was dissolved in DCM (50 mL), dried over anhydrous sodium sulfate and concentrated in vacuo to afford the title compound (220 mg, 11%) which was used in next step immediately without further purification. The solid material was removed by filtration The filtrate was concentrated in vacuo at 30-40° C The residue was dissolved in DCM (50 mL) dried over anhydrous sodium sulfate concentrated in vacuo