反应详情

To a suspension of glutaric anhydride (3.42 g, 30 mmol) and benzimidazol-2(3H)-one (4.02 g, 30 mmol) in tetrachloroethane (100 ml), was added aluminium chloride from a freshly opened container (14.0 g, 105 mmol) in small portions. This mixture was heated to 120 C for 105 min, cooled to room temperature, then poured onto a mixture of ice (75 g) and concentrated hydrochloric acid (20 ml). The suspension was stirred overnight to break up solids that had formed. The tetrachloroethane was azeotropically distilled from the mixture with water under reduced pressure, leaving a brown solid suspended in an aqueous phase. The solid was filtered off and washed with dilute aqueous hydrochloric acid, then water. The solid was added to boiling aqueous sodium carbonate (5% w/v, 150 ml) and the solution filtered. Decolourizing charcoal was added to the cooled filtrate, which was then boiled for 5 min. The charcoal was removed by filtration, and the filtrate treated with concentrated hydrochloric acid until the pH of the solution was 4. The precipitated solid was allowed to stir overnight, filtered off, and dried in a vacuum oven at 50 C/20 mmHg until a constant weight was achieved (1.6 g of brown solid). Nmr indicates that some starting material still remains. Recrystallization of a portion of this solid from acetic acid, as indicated by Kosyakovskaya, did not afford recovery of any product. A portion of the brown solid (300 mg) was dissolved in aqueous sodium bicarbonate (5% w/v, 10 ml) and insoluble material removed by filtration. The filtrate was acidified with concentrated hydrochloric acid and the precipitate formed filtered off and dried at the pump (30 mg).

1. temperatureThis mixture was heated to 120 C for 105 min
2. customhad formed
3. distillationThe tetrachloroethane was azeotropically distilled from the mixture with water under reduced pressure
4. customleaving a brown solid
5. filtrationThe solid was filtered off
6. washwashed with dilute aqueous hydrochloric acid
7. additionThe solid was added
8. filtrationthe solution filtered
9. additionDecolourizing charcoal was added to the cooled filtrate, which
10. waitwas then boiled for 5 min
11. customThe charcoal was removed by filtration
12. additionthe filtrate treated with concentrated hydrochloric acid until the pH of the solution
13. stirringto stir overnight
14. filtrationfiltered off
15. customdried in a vacuum oven at 50 C/20 mmHg until a constant weight
16. customRecrystallization of a portion of this solid from acetic acid
17. customdid not afford recovery of any product
18. custominsoluble material removed by filtration
19. customthe precipitate formed
20. filtrationfiltered off
21. customdried at the pump (30 mg)