反应详情

A solution of 5-fluoroindole (5 g, 37.0 mmol) in DMF (40 mL) was treated at 0° C. with trifluoroacetic anhydride (6.1 mL, 42.6 mmol). After 30 min, the reaction was poured into water and the resulting precipitate collected by filtration, washed with water, then dried in vacuo. The solid was then dissolved in 10% aqueous NaOH (200 mL) and heated at reflux for 1 h. The reaction mixture was then cooled, washed with dichloromethane and acidified with aqueous HCl. The resulting white precipitate was collected by filtration, washed with water, taken up in dichloromethane, washed with water, dried (MgSO4) and evaporated in vacuo. The resulting material (5 g, 75%) was dissolved in methanol (80 mL) and treated with concentrated sulphuric acid (2 mL) then heated at reflux overnight. The reaction was cooled and the resulting precipitate collected, washed with water and evaporated in vacuo to give 5-fluoro-1H-indole-3-carboxylic acid methyl ester as a peach-coloured solid (4.5 g, 83%).

1. filtrationthe resulting precipitate collected by filtration
2. washwashed with water
3. customdried in vacuo
4. dissolutionThe solid was then dissolved in 10% aqueous NaOH (200 mL)
5. temperatureheated
6. temperatureat reflux for 1 h
7. temperatureThe reaction mixture was then cooled
8. washwashed with dichloromethane
9. filtrationThe resulting white precipitate was collected by filtration
10. washwashed with water
11. washwashed with water
12. dry with materialdried (MgSO4)
13. customevaporated in vacuo
14. dissolutionThe resulting material (5 g, 75%) was dissolved in methanol (80 mL)
15. additiontreated with concentrated sulphuric acid (2 mL)
16. temperaturethen heated
17. temperatureat reflux overnight
18. temperatureThe reaction was cooled
19. customthe resulting precipitate collected
20. washwashed with water
21. customevaporated in vacuo