反应详情

A solution of methyl 3-(ethoxycarbonylacetamido)-3-methylbutyrate (45 g) and sodium metal (4.22 g) in anhydrous methanol (450 ml) was heated at a reflux for 3 hours. The cooled mixture was evaporated under reduced pressure and the residue dissolved in water (200 ml). The aqueous solution was washed with ether (3×100 ml), acidified with 2N hydrochloric acid and the acidic mixture extracted with dichloromethane (3×100 ml). The combined extracts were washed with water (2×100 ml), dried over magnesium sulphate and evaporated under reduced pressure to give methyl 6,6-dimethylpiperidine-2,4-dione-3-carboxylate (26.3 g), mp 170°-172° C., as a cream crystalline solid.

1. temperaturea reflux for 3 hours
2. customThe cooled mixture was evaporated under reduced pressure
3. dissolutionthe residue dissolved in water (200 ml)
4. washThe aqueous solution was washed with ether (3×100 ml)
5. extractionthe acidic mixture extracted with dichloromethane (3×100 ml)
6. washThe combined extracts were washed with water (2×100 ml)
7. dry with materialdried over magnesium sulphate
8. customevaporated under reduced pressure