(3-Fluoro-2-nitrophenyl)acetic acid → 7-Fluoro-2,3-dihydro-1h-indol-2-one

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Reaction Steps

(3-fluoro-2-nitro-phenyl)-acetic acid (9.6 g, 48 mmol) was dissolved in acetic acid (100 mL) and hydrogenated over 10% palladium on carbon (1.3 g), at 50 psi for 24 hours. The catalyst was removed by filtration through the Celite® reagent and the solvent was evaporated. The mixture was then dissolved in ethanol (100 mL), para-toluenesulfonic acid (50 mg) was added and the mixture heated under reflux for 1 hour. The mixture was cooled, poured into water, extracted with ethyl acetate, dried (MgSO4), and evaporated. The solid was triturated with hexane/ethyl acetate (95/5) to give 7-fluoro-1,3-dihydro-indol-2-one (6 g, 83%). HRMS: calc'd for C8H6FNO, 151.0433; found (ESI, [M+H]+), 152.0515

Provenance & Evidence