Hydrochloric Acid → 5-Bromo-7-nitroindoline

Participants

Reaction Steps

5.05 g (17.7 mmol) of 1-acetyl-5-bromo-7-nitroindoline was dissolved into a mixed solution of 6 ml of ethanol and 40 ml of 6 N hydrochloric acid, followed by heating under reflux for 3 hours. After neutralizing by adding sodium carbonate thereto, the mixture was extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and concentrated. Then, the residue was purified by silica gel column chromatography, to give 4.13 g of 5-bromo-7-nitroindoline. 301 mg (1.24 mmol) of this compound was added to 10 ml of toluene, and then 580 mg (2.55 mmol) of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone was added thereto. After heating under reflux for 3.5 hours while stirring, the insoluble matters were filtered off and the filtrate was concentrated. The residue was purified by silica gel column chromatography, to give 252 mg of the title compound.

Provenance & Evidence