Sulfuric Acid → 4-Chloro-2,3-dioxo-2,3-dihydro-1H-indole-5-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

2-chloro-4-[(-2-(hydroxyimino)ethanoyl)amino]benzoic acid (300 mg, 1.24 mmol) was dissolved in concentrated sulfuric acid (5 mL). It was stirred at 80° C. for 3 h. The reaction mixture was cooled to rt, poured into ice water and it was extracted twice with ethylacetate. The title compound was obtained as an orange solid (256 mg, 92%) containing 12% of the regioisomer (6-chloro-2,3-dioxoindoline-5-carboxylic acid).

Provenance & Evidence