Boron tribromide → (6-Hydroxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester

HRID 250263Notes

Reaction equation

HRID 250263 reaction equation
[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[C:7]2[CH:14]=[CH:13][C:12]([O:15]C)=[CH:11][C:8]=2[S:9][CH:10]=1)[CH3:2].B(Br)(Br)Br>ClCCl>[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[C:7]2[CH:14]=[CH:13][C:12]([OH:15])=[CH:11][C:8]=2[S:9][CH:10]=1)[CH3:2]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 21816275Ethyl 2-(6-methoxybenzo[b]thiophen-3-yl)acetate

Product 1

HCID 57431998(6-Hydroxy-benzo[b]thiophen-3-yl)-acetic acid ethyl esterYield 93.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a −78° C. solution of (6-methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester (3.81 g, 15.22 mmol) in dichloromethane (50 mL) is added boron tribromide (38.1 mL, 38.1 mmol) dropwise. The mixture is allowed to warm to room temperature and stirred for 16 hours. The mixture is cooled to 0° C. and quenched with water (100 mL). The organic layer is separated, and the aqueous layer is extracted with EtOAc (50 mL). The combined organic layers are dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product is purified by flash chromatography eluting with 30-40% EtOAc/Hexanes. The appropriate fractions are combined and concentrated under reduced pressure to afford the title compound (3.35 g, 93%). ES/MS m/e 237.0 (M+1); 235.0 (M−1).

Workup

  1. temperatureThe mixture is cooled to 0° C.
  2. customquenched with water (100 mL)
  3. customThe organic layer is separated
  4. extractionthe aqueous layer is extracted with EtOAc (50 mL)
  5. dry with materialThe combined organic layers are dried over Na2SO4
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customThe crude product is purified by flash chromatography
  9. washeluting with 30-40% EtOAc/Hexanes
  10. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-78c143d3d3194da7a98c4d99967daa1d
Source dataset
uspto-grants-2011_01
Patent number
US07863302B2

Reaction notes

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