Bromine → 5-Bromo-7-fluoroindolin-2-one

Participants

Reaction Steps

7-Fluoroindolin-2-one (800 mg, 5293 μmol) was taken up in 30 mL of boiling water. Br2 (273 μL, 5293 μmol) and KBr (1260 mg, 10586 μmol) were added dropwise in 5 mL of water over 10 minutes. A white precipitate began to form as the solution was added. The mixture was stirred for 20 minutes. The mixture was then chilled in an ice bath for 30 minutes, washed with 30 mL of a saturated NaHCO3 solution and extracted twice with 50 mL of EtOAc. The organic layers were concentrated and purified with silica gel column chromatography, eluting with 0-35% EtOAc/hexane to give 5-bromo-7-fluoroindolin-2-one (913 mg, 75% yield). MS m/z: 230 (M+1). 1H NMR (400 MHz, CDCl3) δ ppm 3.58 (s, 2H), 7.20 (dd, J=10.07, 0.88 Hz, 2H), 7.63 (s, 1H).

Provenance & Evidence