反应详情

97.8 g of 5,6-dimethoxyindoline are dissolved in 400 ml of 47% hydrobromic acid and the solution is refluxed for four hours. The hydrobromic acid is evaporated under reduced pressure and the residue is taken up in 0.5 l of ethanol and treated with active charcoal under ethanol reflux for 30 minutes and the mixture is then filtered through celite. A volume of ethyl ether is then added progressively to the cooled filtrate. 94.8 g of 5,6-dihydroxyindoline hydrobromide are obtained.

1. temperaturethe solution is refluxed for four hours
2. customThe hydrobromic acid is evaporated under reduced pressure
3. additiontreated with active charcoal under ethanol
4. temperaturereflux for 30 minutes
5. filtrationthe mixture is then filtered through celite
6. additionA volume of ethyl ether is then added progressively to the cooled filtrate