反应详情

A mixture of 34.1 parts of ethyl 3-ethoxy-4,4-dimethoxy-1-piperidinecarboxylate and 1110 parts of a sulfuric acid solution 1% in water was stirred and refluxed for 3 hours. The reaction mixture was cooled and saturated with sodium carbonate. The product was extracted with dichloromethane. The extract was washed with a small amount of water, dried, filtered and evaporated. The residue was stirred in petroleumether. The product was separated and distilled, yielding 21.1 parts of ethyl 3-ethoxy-4-oxo-1-piperidinecarboxylate bp. ±95° C. at 0.05 mm. pressure (intermediate 68).

1. temperaturerefluxed for 3 hours
2. extractionThe product was extracted with dichloromethane
3. washThe extract was washed with a small amount of water
4. customdried
5. filtrationfiltered
6. customevaporated
7. stirringThe residue was stirred in petroleumether
8. customThe product was separated
9. distillationdistilled