2,4-Dihydroxybenzaldehyde → 3-[(2,4-Dihydroxyphenyl)methylidene]-1,3-dihydro-2H-indol-2-one

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Reaction Steps

A mixture of 1.33 g of indole-2-one (10 mmol), 1.38 g of 2,4-dihydroxybenzaldehyde (10 mmol) and 3 drops of piperidine are refluxed in 40 ml of ethanol for 5 hours. The desired product precipitates as a yellow solid during the reaction. After cooling to room temperature, the product is filtered off, washed with ethanol and dried in vacuo. Yield 1.28 g (51%).

Provenance & Evidence