Reaction #657284

Reaction equation

1-methoxy-4-methylamino-piperidine-4-carboxylic acid hydrochloride salt

methanol

thionyl chloride

→

1-methoxy-4-methylamino-piperidine-4-carboxylic acid methyl ester

Conditions

Workup

1. 1
   Temperaturethe reaction mixture was heated
2. 2
   Temperatureat reflux for 7 days
3. 3
   TemperatureAfter cooling
4. 4
   Concentrationthe mixture was concentrated
5. 5
   workup.ADDITIONthe residue diluted with ice water and neutralised with aqueous sodium bicarbonate
6. 6
   ExtractionThe aqueous phase was extracted with ethyl acetate (4×)
7. 7
   Washthe combined organic layers washed with brine
8. 8
   Dryingdried over sodium sulfate
9. 9
   Concentrationconcentrated
10. 10
    OtherThe residue was purified by chromatography on silica gel (gradient ethyl acetate→ethyl acetate/methanol 20:1)

Procedure

To a suspension of 1-methoxy-4-methylamino-piperidine-4-carboxylic acid hydrochloride salt (2.08 g, 9.26 mmol) in methanol (20 ml) at 0-5° C. was added thionyl chloride (2.41 ml, 3.97 g, 33.40 mmol) and the reaction mixture was heated at reflux for 7 days. After cooling, the mixture was concentrated, the residue diluted with ice water and neutralised with aqueous sodium bicarbonate. The aqueous phase was extracted with ethyl acetate (4×), the combined organic layers washed with brine, dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel (gradient ethyl acetate→ethyl acetate/methanol 20:1). Yield: 76 mg of 1-methoxy-4-methylamino-piperidine-4-carboxylic acid methyl ester (title compound P5.4) as an oil.

Source