Hydrochloric Acid → 6-Fluoro-1,3-dihydro-5-methyl-2H-indol-2-one

Participants

Reaction Steps

An intimate mixture of 11.62 g (57.6 mmol) of N-(2-chloroacetyl)-3-fluoro-4-methylaniline and 30.6 g (229.5 mmol) of anhydrous aluminum chloride was heated to 210°-220° C. After 4 hours, the reaction mixture was cooled and then added to 100 ml of 1N hydrochloric acid and 50 ml of ice. A tan solid formed, which was collected by filtration and recrystallized from aqueous ethanol. Three crops were obtained, weighing 4.49 g, 2.28 g and 1.0 g, respectively. The first two crops comprised a mixture of isomers (4-fluoro-5-methyl and 6-fluoro-5-methyl-2-oxindoles). The crop weighing 1.0 g was further recrystallized from water to give 280 mg of the title compound, mp 168.5°-171° C.

Provenance & Evidence