反应详情

To a solution of 20% sodium ethoxide•ethanol solution (34.0 g) diluted with ethanol (40 ml) was added a solution of diethyl malonate (16.0 g) in ethanol (40 ml) dropwise over 30 minutes in ice-cooling. After stirring in ice-cooling for additional 30 minutes, thereto was added 2-chloroacetamide (4.7 g) in one portion and the mixture was stirred in ice-cooling for 30 minutes and then at room temperature for 20 hours. The white solid precipitated was collected by filtering and washed with a small amount of ethanol. This white solid was dissolved in water (300 ml) and this resulting aqueous solution was acidified with conc. hydrochloric acid and extracted with dichloromethane (50 ml) three times. The extract was dried over magnesium sulfate, filtered and concentrated to give a yellow oil. This was purified by a flash column chromatography (n-hexane:ethyl acetate=2:1→1:1) to give ethyl 2,5-dioxopyrrolidine-3-carboxylate (5.63 g, 66%).

1. temperaturecooling
2. temperaturecooling for additional 30 minutes
3. stirringthe mixture was stirred in ice-
4. temperaturecooling for 30 minutes
5. customThe white solid precipitated
6. customwas collected
7. filtrationby filtering
8. washwashed with a small amount of ethanol
9. dissolutionThis white solid was dissolved in water (300 ml)
10. extractionextracted with dichloromethane (50 ml) three times
11. dry with materialThe extract was dried over magnesium sulfate
12. filtrationfiltered
13. concentrationconcentrated
14. customto give a yellow oil
15. customThis was purified by a flash column chromatography (n-hexane:ethyl acetate=2:1→1:1)