Boron tribromide → 4-fluoro-2-methyl-1H-indol-5-ol

HRID 2180114Notes

Reaction equation

HRID 2180114 reaction equation
[F:1][C:2]1[C:10]([O:11]C)=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[C:5]([CH3:13])[NH:6]2.B(Br)(Br)Br>C(Cl)Cl>[F:1][C:2]1[C:10]([OH:11])=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[C:5]([CH3:13])[NH:6]2

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 220307284-Fluoro-5-methoxy-2-methyl-1H-indole

Product 1

HCID 103520364-fluoro-2-methyl-1H-indol-5-olYield 70.7%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent3×

Procedure

To a solution of 4-fluoro-5-methoxy-2-methylindole (709 mg, 3.95 mmol) in methylene chloride (9 ml) cooled at −30° C. was added a solution of boron tribromide (2.18 g, 8.7 mmol) in methylene chloride (1 ml). After stirring for 1 hour at ambient temperature, the mixture was poured onto water and was diluted with methylene chloride. The pH of the aqueous layer was adjusted to 6. The organic layer was separated, washed with water, brine, dried (MgSO4) and evaporated. The residue was purified by column chromatography, eluting with ethyl acetate/petroleum ether (3/7) to give 4-fluoro-5-hydroxy-2-methylindole (461 mg, 70%).

Workup

  1. additionthe mixture was poured onto water
  2. customThe organic layer was separated
  3. washwashed with water, brine
  4. dry with materialdried (MgSO4)
  5. customevaporated
  6. customThe residue was purified by column chromatography
  7. washeluting with ethyl acetate/petroleum ether (3/7)

Sources & evidence

ORD record
ord-5792d1df8434498ba89cb527f4c5f7d9
Source dataset
uspto-grants-2005_05
Patent number
US06887874B2

Reaction notes

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