Nitric Acid → 7-Fluoro-5-nitroindolin-2-one

Participants

Reaction Conditions

Reaction Steps

7-fluoro-1,3-dihydro-2H-indol-2-one (8.0 g, 52.9 mmol) was slurried in H2SO4 (conc., 86 ml) and the mixture cooled to −45° C. A solution of fuming nitric acid (>90%, 3.34 g, 52.9 mmol) in H2SO4 (20 ml) was added drop wise, while maintaining the temperature at −45° C. throughout the addition. The mixture was allowed to slowly warm to RT and stirred overnight. The mixture was poured into stirred ice-cold water (1500 ml). A white precipitate resulted, and the slurry was aged at 0° C. for 1 hour. The solid was collected by filtration, triturated with cold water (2×), and dissolved into EtOAc (1 L). This solution was washed with basic brine (containing sodium bicarbonate), dried over Na2SO4, filtered, and the volatiles removed in vacuum to give the titled compound.

Provenance & Evidence