Acetyl chloride → 1-(7-Nitro-1H-indol-3-YL)ethanone

Participants

Reaction Steps

A 1.0M solution (11 ml) of dimethylaluminum chloride (11 mmol) in hexane was added to 50 ml of a solution of 1.2 g (7.5 mmol) of 7-nitro-1H-indole in dichloromethane at 0° C. in a nitrogen atmosphere, followed by the addition of 2.1 ml (29.5 mmol) of acetyl chloride at 0° C. The obtained mixture was stirred at room temperature for 4 hours, followed by the addition of a saturated aqueous solution of ammonium chloride. The precipitate thus formed was recovered by filtration and washed with hot ethanol sufficiently. The washings and the filtrate were combined and concentrated. Water was added to the residue and the resulting mixture was extracted with ethyl acetate. The organic phase was washed with a saturated aqueous solution of common salt, dried over magnesium sulfate and distilled in a vacuum to remove the solvent. The residue was purified by silica gel column chromatography to give 3-acetyl-7-nitro-1H-indole. This product was dissolved in 100 ml of methanol and hydrogenated in the presence of palladium-carbon at ordinary temperature under normal pressure. After the removal of the catalyst by filtration, the filtrate was concentrated to dryness to give 790 mg of the title compound.

Provenance & Evidence