Hydrogen Bromide → 5,6-Dihydroxyindoline hydrobromide

Participants

Reaction Steps

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.

Provenance & Evidence