Acetyl chloride → 5-acetyl-2,3-dihydro-1H-indol-2-one

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Reaction Steps

171 g (1.28 mol) aluminium chloride in 500 ml 1,2-dichloroethane are cooled in the ice bath. Then 78 g (1.1 mol) acetylchloride are added dropwise, so that the temperature does not exceed 10° C. After 1 h, 71.3 g (0.53 mol) 2-indolinone (1,3-dihydro-indol-2-one) are added in 4 batches and the temperature is kept at 10–12° C. The reaction mixture is left overnight to warm up slowly to ambient temperature. Then the solution is slowly added to 1 kg ice with vigorous stirring. The slurry is diluted with 1 l water and stirred for another 30 min. Then the precipitate is suction filtered.

Provenance & Evidence