Ethyl chloroformate → Ethyl 5-bromo-3-oxo-2,3-dihydro-1-benzofuran-2-carboxylate

HRID 931375Notes

Reaction equation

HRID 931375 reaction equation
C(=O)([O-])[O-].[K+].[K+].[Br:7][C:8]1[CH:9]=[CH:10][C:11]2[O:15][CH2:14][C:13](=[O:16])[C:12]=2[CH:17]=1.Cl[C:19]([O:21][CH2:22][CH3:23])=[O:20]>CC(C)=O>[Br:7][C:8]1[CH:9]=[CH:10][C:11]2[O:15][CH:14]([C:19]([O:21][CH2:22][CH3:23])=[O:20])[C:13](=[O:16])[C:12]=2[CH:17]=1

Participants

5

Reactant 3

HCID 10928Ethyl chloroformateHCID 11430Potassium CarbonateHCID 105127485-Bromobenzo[b]furan-3(2H)-one

Product 1

HCID 58458886Ethyl 5-bromo-3-oxo-2,3-dihydro-1-benzofuran-2-carboxylate

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

Potassium carbonate (1.66 g, 12 mmol) is added to a solution of 5-bromo-1-benzofuran-3(2H)-one (2.13 g, 10 mmol) in acetone (25 mL). The stirred mixture is treated dropwise with ethyl chloroformate (1.05 mL, 11 mmol). The mixture is then heated at reflux for 18 h. The solids are filtered off and the filtrate concentrated in vacuo. The residue is partitioned between EtOAc and saturated aqueous NaHCO3. The layers are separated and the organic layer washed with brine, dried (Na2SO4), filtered and concentrated in vacuo. The residue is purified by silica gel chromatography (gradient elution with hexanes-EtOAc) to afford the title compound.

Workup

  1. temperatureThe mixture is then heated
  2. temperatureat reflux for 18 h
  3. filtrationThe solids are filtered off
  4. concentrationthe filtrate concentrated in vacuo
  5. customThe residue is partitioned between EtOAc and saturated aqueous NaHCO3
  6. customThe layers are separated
  7. washthe organic layer washed with brine
  8. dry with materialdried (Na2SO4)
  9. filtrationfiltered
  10. concentrationconcentrated in vacuo
  11. customThe residue is purified by silica gel chromatography (gradient elution with hexanes-EtOAc)

Sources & evidence

ORD record
ord-591bf07ed2904349b7415ea6bc6a6304
Source dataset
uspto-grants-2016_03
Patent number
US09296750B2

Reaction notes

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