Azobisisobutyronitrile → Ethyl 5-(bromomethyl)-1-benzofuran-2-carboxylate

HRID 252805Notes

Reaction equation

HRID 252805 reaction equation
[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([C:10]([O:12][CH2:13][CH3:14])=[O:11])=[CH:7][C:6]=2[CH:15]=1.[Br:16]N1C(=O)CCC1=O.CC(N=NC(C#N)(C)C)(C#N)C>C(Cl)(Cl)(Cl)Cl.ClCCl>[Br:16][CH2:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([C:10]([O:12][CH2:13][CH3:14])=[O:11])=[CH:7][C:6]=2[CH:15]=1

Participants

6

Reactant 3

HCID 6547AzobisisobutyronitrileHCID 67184N-bromobutanimideHCID 13157013Ethyl 5-methyl-1-benzofuran-2-carboxylate

Product 1

HCID 15675414Ethyl 5-(bromomethyl)-1-benzofuran-2-carboxylate

Reagents, catalysts & solvents 2

HCID 5943Carbon TetrachlorideSolventHCID 6344DichloromethaneSolvent

Procedure

A mixture of the ester 25 (2.26 g, 11.1 mmol), JV-bromosuccinimide (2.37 g, 13.3 mmol) and VAZO (271 mg, 1.11 mmol) was refluxed overnight in CCl4 (50 mL) under nitrogen. The reaction mixture was cooled to the room temperature, diluted with dichloromethane and washed with water. The organic layer was dried over anhydrous MgSO4 and concentrated in vacuum. The residue was purified by flash chromatography (eluent 5% EtOAc in hexane) to give ethyl 5-bromomethyl-benzofuran-2-carboxylate. This compound was dissolved in dioxane (20 ml) and a solution of NaHCO3 (1.76 g, 20.9 mmol) in water (20 ml) was added. The reaction was stirred at 80° C. during 16 h. The solvent was evaporated and the product was dissolved in EtOAc and washed with brine. The organic layer was dried over anhydrous MgSO4 and concentrated in vacuum. The residue was purified by flash chromatography (eluent 20-40% EtOAc in hexane to give the title compound 26 (2.55 g, 61%) as a white solid. 1H-NMR (DMSO) δ: 7.74 (d, J=1.0 Hz, 1H), 7.71-7.70 (m, 1H), 7.65 (d, J=8.6 Hz, 1H), 7.44 (dd, J=8.6, 1.8 Hz, 1H), 5.31 (t, J=5.8 Hz, 1H), 4.59 (d, J=5.7 Hz, 2H), 4.35 (q, J=7.1 Hz, 2H); 1.34 (t, J=7.0, 3H).

Workup

  1. washwashed with water
  2. dry with materialThe organic layer was dried over anhydrous MgSO4
  3. concentrationconcentrated in vacuum
  4. customThe residue was purified by flash chromatography (eluent 5% EtOAc in hexane)

Sources & evidence

ORD record
ord-7b06c6a9e9ab436685facddfdde90227
Source dataset
uspto-grants-2011_01
Patent number
US07868205B2

Reaction notes

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