Nitric Acid → 5-Nitro-2-oxindole

Participants

Reaction Conditions

Reaction Steps

2-Oxindole (6.5 g) was dissolved in concentrated sulfuric acid (25 ml) and the mixture maintained at −10 to 15° C. while fuming nitric acid (2.1 ml) was added dropwise. After the addition of the nitric acid the reaction mixture was stirred at 0° C. for 0.5 hour and poured into ice-water. The precipitate which formed was collected by filtration, washed with water and crystallized from 50% acetic acid. The final crystalline product was then filtered, washed with water and dried under vacuum to give 6.3 g (70%) of 5-nitro-2-oxindole.

Provenance & Evidence