Sulfuric Acid → 4,5-Dimethylisatin

Participants

Reaction Conditions

Reaction Steps

To a solution of concentrated sulfuric acid (85 ml) in water (17 ml) there was slowly added N-(3,4-dimethylphenyl)-2-hydroxyimino-acetamide (30 g, 0.156 mmol), and the mixture was stirred at 85° C. for 2 hours. The obtained solution was poured into ice water, and the precipitated orange solid was filtered out. The obtained solid was dissolved in 10% aqueous sodium hydroxide, active carbon was added, and the mixture was stirred. The obtained solution was filtered, and acetic acid was used for acidification to obtain 4,5-dimethyl-1H-indole-2,3-dione as crystals.

Provenance & Evidence