反应详情

1-Acetyl-3-(2-acetoxyethyl)-4,6-dimethylindoline (2.0 g) was dissolved in AcOH (40 ml) and Br2 (1.9 g) was added, which was followed by stirring at room temperature for 30 min. The reaction mixture was poured into ice water and precipitate was collected by filtration. The precipitate was dissolved in CHCl3, and the mixture was washed with water and dried over anhydrous sodium sulfate. CHCl3 was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: CHCl3 /MeOH=50/1-10/1) to give 2.7 g of crude crystals of 1-acetyl-3-(2-acetoxyethyl)-5-bromo-4,6-dimethylindoline. The crude crystals were added by portions to a mixture of nitric acid (0.47 ml), AcOH (10 ml) and conc. hydrochloric acid (10 ml) under ice-cooling, and the mixture was stirred at the same temperature for 4 hr. The reaction mixture was poured into ice water and precipitate was collected by filtration. The precipitate was dissolved in CHCl3. After washing with water, the mixture was dried over anhydrous sodium sulfate and CHCl3 was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: CHCl3 /MeOH=50/1-10/1) to give 1.4 g of 1-acetyl-3-(2-acetoxyethyl)-5-bromo-4,6-dimethyl-7-nitroindoline.

1. filtrationwas collected by filtration
2. dissolutionThe precipitate was dissolved in CHCl3
3. washthe mixture was washed with water
4. dry with materialdried over anhydrous sodium sulfate
5. customCHCl3 was evaporated under reduced pressure
6. customThe residue was purified by silica gel column chromatography (eluent: CHCl3 /MeOH=50/1-10/1)
7. customto give 2.7 g of crude crystals of 1-acetyl-3-(2-acetoxyethyl)-5-bromo-4,6-dimethylindoline
8. temperaturecooling
9. stirringthe mixture was stirred at the same temperature for 4 hr
10. filtrationwas collected by filtration
11. dissolutionThe precipitate was dissolved in CHCl3
12. washAfter washing with water
13. dry with materialthe mixture was dried over anhydrous sodium sulfate and CHCl3
14. customwas evaporated under reduced pressure
15. customThe residue was purified by silica gel column chromatography (eluent: CHCl3 /MeOH=50/1-10/1)