反应详情

温度

90 °C

5-Oxo-2-pyrrolidinepropanoic acid (15.7 g, 0.1 mol) was added to 45 ml of acetic anhydride and the mixture was heated slowly to 90° C. and held at that temperature for six hours. The mixture was cooled and the volatile materials stripped off at a temperature of 60° C. under vacuum. The residue (14.2 g) was dissolved in 230 ml of isopropyl alcohol, the solution decolorized, filtered, and concentrated to 30 ml. This solution was cooled 0°-5° C. for two hours, and the solid which separated was collected by filtration, washed twice with 25-ml portions of isopropyl alcohol to yield 12.5 g (89.9%) of dihydro-1H-pyrrolizine-3,5-(2H,6H)-dione, mp 180.2°-181.8° C. which was found to be 99.5% pure by high pressure liquid chromatographic (HPLC) analysis.

1. temperatureThe mixture was cooled
2. customstripped off at a temperature of 60° C. under vacuum
3. filtrationfiltered
4. concentrationconcentrated to 30 ml
5. temperatureThis solution was cooled 0°-5° C. for two hours
6. customthe solid which separated
7. filtrationwas collected by filtration
8. washwashed twice with 25-ml portions of isopropyl alcohol