Sodium Hydroxide → 6-Amino-5-fluoroindolin-2-one

Participants

Reaction Steps

(2,4-Diamino-5-fluoro-phenyl)-acetic acid 9c (7.12 g, 38.7 mmol) was dissolved in 100 mL of hydrochloric acid (1 M) under stirring at room temperature, and the reaction solution was heated to reflux for 1 hour. The reaction was completed until TLC showed the disappearance of starting materials. The reaction mixture was naturally cooled down to room temperature, followed by an ice-water bath cooling, and 100 mL of sodium hydroxide solution (1M) was then added dropwise to neutralize the reaction solution. The mixture was extracted with ethyl acetate (125 mL ×4). The combined organic extracts were washed with saturated brine (100 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give the title compound 5-fluoro-6-amino-1,3-dihydro-indol-2-one 9d (5.3 g, yield 82.8%) as a yellow solid.

Provenance & Evidence