Nitric Acid → 5-Bromo-7-nitroisatin

Participants

Reaction Steps

To a solution of 5-bromo-1H-indole-2,3-dione (5 g, 22.1 mmol) in conc. H2SO4 (22.5 mL) was added fuming nitric acid (1.45 mL) very slowly at −5 to 0° C. The reaction mixture was stirred at the same temperature for one hour. After completion of the reaction, the reaction mixture was poured on to crushed ice and the resulting precipitate was filtered, washed with water (2-3 times) and dried under vacuum to obtain the title compound as yellow solid (5.5 g, 91.8%) which was used for the next step directly.

Provenance & Evidence