反应详情

A mixture of concentrated sulfuric acid (3.6 mL) and concentrated nitric acid (0.7 mL) was added slowly to a solution of 4-bromo-1,3-dihydro -2H-indol-2-one (2 g, 9.48 mmol) (prepared according to T. Kosuge et al., Chem. Pharm. Bull. 33(4):1414-1418 (1985)) in concentrated sulfuric acid (20 mL) at −5° C., with stirring. The mixture was stirred for an additional 1 h at −5° C., then poured in ice. After standing for 1 h, precipitate formed was collected by filtration and washed with water, and dried in a vacuum oven to give 4-bromo-1,3-dihydro-5-nitro-2H-indol-2-one. (Yield 2.33 g, 96%).

1. stirringThe mixture was stirred for an additional 1 h at −5° C.
2. additionpoured in ice
3. customprecipitate formed
4. filtrationwas collected by filtration
5. washwashed with water
6. customdried in a vacuum oven