Sulfuric Acid → 4,5-Dimethylisatin

Participants

Reaction Conditions

Reaction Steps

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

Provenance & Evidence