反应详情

温度

98 °C

Twenty-eight grams of dihydro-1H-pyrrolizine-3,5(2H,6H)-dione (III) are dissolved in 76 g of benzyl alcohol and 0.2 ml of concentrated hydrochloric acid is added. The solution is heated at 98° C. for 104 hours. The mixture is cooled and excess benzyl alcohol is distilled at 0.1 mm pressure to a maximum bath temperature of 100° C. The residual oil is dissolved in 1 l of anhydrous diethylether, 1 g of activated charcoal is added and the resulting suspension is filtered through filter aid. The filtrate is concentrated at reduced pressure and the resulting crystals are isolated by filtration. Recrystallization from cyclohexane containing 12% methylene chloride yields 5-oxo-2-pyrrolidinepropanoic acid benzyl ester with a melting point of 79°-80° C.

1. temperatureThe mixture is cooled
2. distillationexcess benzyl alcohol is distilled at 0.1 mm pressure to a maximum bath temperature of 100° C
3. dissolutionThe residual oil is dissolved in 1 l of anhydrous diethylether
4. addition1 g of activated charcoal is added
5. filtrationthe resulting suspension is filtered
6. filtrationthrough filter aid
7. concentrationThe filtrate is concentrated at reduced pressure
8. customthe resulting crystals are isolated by filtration
9. customRecrystallization from cyclohexane containing 12% methylene chloride