Boron tribromide → 6-Bromo-5-hydroxy-1H-indole-2-carboxylic acid ethyl ester

HRID 493991Notes

Reaction equation

HRID 493991 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][C:11]([O:15]C)=[C:10]([Br:17])[CH:9]=2)=[O:5])[CH3:2].B(Br)(Br)Br.C(=O)(O)[O-].[Na+]>ClCCl>[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][C:11]([OH:15])=[C:10]([Br:17])[CH:9]=2)=[O:5])[CH3:2]

Participants

5

Reactant 3

HCID 25134Boron tribromideHCID 516892Sodium BicarbonateHCID 14546582HCID 14546582, compound

Product 1

HCID 670179076-Bromo-5-hydroxy-1H-indole-2-carboxylic acid ethyl esterYield 72.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

The solution of 8.30 g (27.8 mmol) 6-bromo-5-methoxy-1H-indole-2-carboxylic acid ethyl ester (prepared according to J. Org. Chem. 1974, 39, 3580) in 160 mL dichloromethane was cooled to −78° C. At this temperature, 55.7 mL boron tribromide (55.7 mmol; 1M solution in dichloromethane) were added. The solution was allowed to warm to room temperature and after 30 min. The solution was poured on 10% aqueous sodium bicarbonate solution, the phases were separated and the aqueous phase was extracted three times with ethyl acetate. The combined organic layers were washed with water followed by brine, dried over magnesium sulfate, filtered and evaporated. The residue was flash-chromatographed on silica gel with n-hexane: ethyl acetate (2:1 v/v) as eluant to give 5.7 g (72%) of the product as a light yellow solid. MS (m/e): 282.2 (M−H+, 100%).

Workup

  1. customthe phases were separated
  2. extractionthe aqueous phase was extracted three times with ethyl acetate
  3. washThe combined organic layers were washed with water
  4. dry with materialdried over magnesium sulfate
  5. filtrationfiltered
  6. customevaporated
  7. customThe residue was flash-chromatographed on silica gel with n-hexane: ethyl acetate (2:1 v/v) as eluant

Sources & evidence

ORD record
ord-7b1742bc8b93473987aad281717736a7
Source dataset
uspto-grants-2009_05
Patent number
US07538101B2

Reaction notes

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