Hydrochloric Acid → 7-Fluoro-2,3-dihydro-1h-indol-2-one

Participants

Reaction Conditions

Reaction Steps

To a mixture of 7-fluoro-1H-indole-2,3-dione (100 g, 0.606 mol) in ethylene glycol (500 mL) was added an aqueous hydrazine solution (54% wt, 73 g, 1.21 mol) dropwise over 30 minutes. The mixture was heated to 120° C. and stirred for 6 hours. The mixture was cooled to room temperature and water (500 mL) was added. Concentrated hydrochloric acid (HCl; 60 mL) was added, the mixture was warmed to about 35 to about 40° C., and the mixture was stirred for 1 hour. The mixture was then cooled to about 0 to about 5° C. The solid compound was filtered, washed with cold water and dried at 55° C. under vacuum to give an off-white solid (76 g) in 83% yield with 96% HPLC purity.

Provenance & Evidence