Acetic Anhydride → Benzofuran, 5-bromo-

HRID 2261073Notes

Reaction equation

HRID 2261073 reaction equation
C([C:3]1[CH:13]=[C:12]([Br:14])[CH:11]=[CH:10][C:4]=1[O:5][CH2:6][C:7](O)=O)=O.C([O-])(=O)C.[Na+].C(OC(=O)C)(=O)C>C(O)(=O)C>[Br:14][C:12]1[CH:13]=[CH:3][C:4]2[O:5][CH:6]=[CH:7][C:10]=2[CH:11]=1

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 517045Sodium AcetateHCID 9688792-(4-bromo-2-formylphenoxy)acetic acid

Product 1

HCID 90015Benzofuran, 5-bromo-Yield 40%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a mixture of 2-formyl-4-bromophenoxy acetic acid (50 g, 0.192 mol), sodium acetate (100 g, 1.21 mol) in acetic acid (250 mL) at 100° C. was added acetic anhydride (100 mL) portions during a period of 3 h. The reaction mixture was then refluxed for 20 h. The solvent was removed by distillation and residue diluted with 3N HCl (500 mL) and refluxed for 2 h. The reaction mixture was then concentrated under vacuum and product extracted with pet. ether (3×200 mL). The organic layer was washed with 10% NaHCO3 solution and evaporated to give 5-bromo-1-benzofuran (15 g, 40%) as a pale yellow liquid.

Workup

  1. temperatureThe reaction mixture was then refluxed for 20 h
  2. customThe solvent was removed by distillation and residue
  3. additiondiluted with 3N HCl (500 mL)
  4. temperaturerefluxed for 2 h
  5. concentrationThe reaction mixture was then concentrated under vacuum and product
  6. extractionextracted with pet. ether (3×200 mL)
  7. washThe organic layer was washed with 10% NaHCO3 solution
  8. customevaporated

Sources & evidence

ORD record
ord-115187c9d5c94aec858b0e67b7151d76
Source dataset
uspto-grants-2010_12
Patent number
US07846925B2

Reaction notes

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