Ethanol → 4-Bromo-5-methoxy-1H-indole-2-carboxylic acid

HRID 454284Notes

Reaction equation

HRID 454284 reaction equation
[Br:1][C:2]1[C:10]([OH:11])=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[C:5]([C:12]([O:14]CC)=[O:13])[NH:6]2.[OH-].[K+].[CH2:19](O)C>O>[Br:1][C:2]1[C:10]([O:11][CH3:19])=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[C:5]([C:12]([OH:14])=[O:13])[NH:6]2

Participants

5

Reactant 3

HCID 702EthanolHCID 14797Potassium HydroxideHCID 22030665Ethyl 4-bromo-5-hydroxyindole-2-carboxylate

Product 1

HCID 133565154-Bromo-5-methoxy-1H-indole-2-carboxylic acidYield 96%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
50 °C

Procedure

Ethyl 4-bromo-5-hydroxyindole-2-carboxylate (1.49 g, 5 mmol), (Jnl. Org. Chem. 1984, 49, 4761), was dissolved in ethanol (10 ml) and water (3.5 ml). Potassium hydroxide (840 mg) was added and the mixture stirred at 50° C. under an atmosphere of nitrogen for 1 hour then cooled to ambient temperature. The solvent was evaporated and the residue re-dissolved in water (25 ml). 2M Aqueous hydrochloric acid was added until the reaction mixture was at pH4, giving a precipitate which was filtered off, washed with water and dried under vacuum to give 4-bromo-5-methoxyindole-2-carboxylic acid (1.30, 96%).

Workup

  1. temperaturethen cooled to ambient temperature
  2. customThe solvent was evaporated
  3. dissolutionthe residue re-dissolved in water (25 ml)
  4. addition2M Aqueous hydrochloric acid was added until the reaction mixture
  5. customgiving a precipitate which
  6. filtrationwas filtered off
  7. washwashed with water
  8. customdried under vacuum

Sources & evidence

ORD record
ord-dd313a13c74441898910f5b983deccd0
Source dataset
uspto-grants-2013_07
Patent number
US08492560B2

Reaction notes

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