Nitric Acid → 7-Amino-5-fluoroindolin-2-one

Participants

Reaction Steps

5-Fluoro-1,3-dihydro-indol-2-one (5.0 g, 33 mmol) was added with 98% sulfuric acid (17.6 ml) and 65%-68% nitric acid (2.1 ml) in an ice-water bath with salt at −5° C. Upon the completion of the addition, the mixture was stirred for 1 hour at room temperature and added with ice-water until precipitate was formed. The solid was filtered and washed with water (50 ml×3) and recrystallized from acetic acid and water to give 7-amino-5-fluoro-1,3-dihydro-indol-2-one (4.0 g, 62.5%) as an orange solid.

Provenance & Evidence