benzyl 2-methyl-3-oxopiperidine-1-carboxylate

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a stirred solution of 309.5 ul (3.530 mmol) oxalyl chloride in 3 ml dichloromethane at −50° C. to −60° C. was added a solution of 873 ul DMSO in 2 ml dichloromethane. The reaction mixture was stirred for 10 minutes, after which a solution of 800 mg (3.209 mmol) 3-hydroxy-2-methyl-piperidine-1-carboxylic acid benzyl ester in 3 ml dichloromethane was added over a period of 10 minutes. Stirring was continued for an additional 30 minutes. To this, was subsequently added 2.24 ml (16.05 mmol) triethylamine. The reaction mixture was stirred for 15 minutes, then allowed to warm to room temperature, taken in water, separated, and the aqueous layer extracted with dichloromethane. The combined organic layers were washed twice with water, dried over sodium sulfate, filtered and concentrated in vacuo. The crude product was purified with flash column chromatography on silica gel (Eluent: Heptane/ethyl acetate 0 to 40) to provide 600 mg (76%) of the title compound as a light yellow oil. MS (m/e): 270.2 (M+Na+). Stirring was continued for an additional 30 minutes The reaction mixture was stirred for 15 minutes separated the aqueous layer extracted with dichloromethane The combined organic layers were washed twice with water dried over sodium sulfate filtered concentrated in vacuo The crude product was purified with flash column chromatography on silica gel (Eluent: Heptane/ethyl acetate 0 to 40)