反应详情

Ethyl isonipecotate (3.0 g, 19.1 mmol) was added to a mixture of 90% formic acid (10 mL) and 30% aqueous formaldehyde (10 mL, 100 mmol) then the mixture was heated at reflux for 24 h. After cooling, the mixture was concentrated in vacuo to give an oil which was dissolved in dichloromethane. Solid sodium bicarbonate (1 g) was added and the mixture stirred for 1 h then filtered. The filtrate was concentrated in vacuo to afford 1-methyl-piperidine-4-carboxylic acid ethyl ester (2.0 g, 61%) as a liquid, which was used as such for the next step.

1. temperaturethe mixture was heated
2. temperatureat reflux for 24 h
3. temperatureAfter cooling
4. concentrationthe mixture was concentrated in vacuo
5. customto give an oil which
6. filtrationthen filtered
7. concentrationThe filtrate was concentrated in vacuo