Hydrochloric Acid → 1-Phenyloxindole

Participants

Reaction Conditions

Reaction Steps

To a solution of commercially available 1-phenyl-1H-indole-2,3-dione (10.10 g, 45.7 mmol) in ethylene glycol (125 mL) is added powdered potassium hydroxide (7.4 g, 112 mmol), hydrazine hydrate (16.35 mL) and water (4 mL). The reaction is heated to 160° C. for 1.5 hr after which it is cooled to room temperature, made acidic with conc. hydrochloric acid, diluted with water and the resulting solids are collected by filtration. The solid is washed with water, dissolved in dichloromethane, dried and the solvent removed to give the 1-phenyl-1H-indol-2-one (8.6 g, 90% yield) as a solid.

Provenance & Evidence