5,6-difluoro-indoline-2,3-dione

370-55-8

774-47-0

GENERAL PROCEDURE: To a stirred 18.1 M aqueous sulfuric acid solution (0.68 mL/mmol), isonitrosoacetanilide (1 equiv.) was added in batches at 60 °C. The reaction mixture was placed in a heating block and stirred at an internal temperature of 80 °C for 30 min, followed by cooling to room temperature. The reaction solution was slowly poured into a saturated ice-water mixture (5 mL/g) and stirred at room temperature for 10 minutes. The resulting solid was collected by filtration, dried and purified according to standard methods.