Boron tribromide → 5-Hydroxybenzofuran-2-carboxylic acid

HRID 964042Notes

Reaction equation

HRID 964042 reaction equation
C([C:3]1[C:7]2[CH:8]=[C:9]([O:12]C)[CH:10]=[CH:11][C:6]=2[O:5][C:4]=1[C:14]([OH:16])=[O:15])C.B(Br)(Br)Br>ClCCl>[OH:12][C:9]1[CH:10]=[CH:11][C:6]2[O:5][C:4]([C:14]([OH:16])=[O:15])=[CH:3][C:7]=2[CH:8]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 19079540Ethyl 5-methoxybenzofuran-2-carboxylic acid

Product 1

HCID 122089725-Hydroxybenzofuran-2-carboxylic acidYield 86.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a stirred solution of ethyl 5-methoxybenzofuran-2-carboxylic acid (5.0 g, 26 mmol) in dichloromethane (CH2Cl2) (100 mL) at 0 ° C. was added boron tribromide (8.6 mL, 91 mmol) and the resulting dark solution was allowed to stir at room temperature for 2 hours. The reaction solution was poured over ice, stirred for 30 minutes and extracted with ethyl acetate, (EtOAc). The organic phase was washed with water, saturated aqueous brine, dried over sodium sulfate, (Na2SO4), and concentrated in vacuo to afford 5-hydroxybenzofuran-2-carboxylic acid (4.0 g; m.p. 223-228° C.).

Workup

  1. additionThe reaction solution was poured over ice
  2. stirringstirred for 30 minutes
  3. extractionextracted with ethyl acetate, (EtOAc)
  4. washThe organic phase was washed with water, saturated aqueous brine
  5. dry with materialdried over sodium sulfate, (Na2SO4),
  6. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-96a1bfefda624adb800b423d6d0f9cfa
Source dataset
uspto-grants-1998_06
Patent number
US05767133

Reaction notes

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