Hydrogen Bromide → 5,6-Dihydroxyindoline hydrobromide

HRID 1646139Notes

Reaction equation

HRID 1646139 reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][C:11]=1[O:12]C)[NH:8][CH2:7][CH2:6]2.[BrH:14]>>[BrH:14].[OH:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][C:11]=1[OH:12])[NH:8][CH2:7][CH2:6]2

Participants

3

Reactant 2

HCID 260Hydrogen BromideHCID 110629785,6-Dimethoxyindoline

Product 1

HCID 220204375,6-Dihydroxyindoline hydrobromideYield 75%

Procedure

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.

Workup

  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

Sources & evidence

ORD record
ord-ee0d0dae436f4a4da08e282089cd025f
Source dataset
uspto-grants-1993_01
Patent number
US05178637

Reaction notes

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