反应详情

温度

5 °C

1.15 g (5 mmol) of 7-bromo-5-chloro-1H-indole were dissolved in 30 ml THF. At a temperature of −75° C. under argon 9.4 ml (15 mmol) of a 1.6 M n-butyl lithium solution in hexane were added dropwise. After complete addition the reaction mixture was stirred at 5° C. for 30 min, cooled to −75° C. and 10 g dry ice was added. The reaction mixture was warmed to rt and stirred for 15 min. It was poured onto 100 ml of water and extracted twice with EtOAc. The aqueous layer was acidified with 1N aqueous HCl solution and extracted twice with DCM. The combined organic layers were dried over sodium sulfate, filtered and the solvent was evaporated. The residue was treated with hexane and stirred for 10 min. The precipitate was filtered, washed with hexane and dried to yield 700 mg (72%) of 5-chloro-1H-indole-7-carboxylic acid as a white solid. MS (ISP) 194.0 (M−H)−.

1. additionAfter complete addition the reaction mixture
2. temperaturecooled to −75° C.
3. temperatureThe reaction mixture was warmed to rt
4. stirringstirred for 15 min
5. extractionextracted twice with EtOAc
6. extractionextracted twice with DCM
7. dry with materialThe combined organic layers were dried over sodium sulfate
8. filtrationfiltered
9. customthe solvent was evaporated
10. additionThe residue was treated with hexane
11. stirringstirred for 10 min
12. filtrationThe precipitate was filtered
13. washwashed with hexane
14. customdried