1,2-Dibromoethane → 8-Bromo-2,3-dihydro-1,4-benzodioxine-6-carbaldehyde

HRID 15324

Reaction equation

HRID 15324 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([OH:11])[C:9]=1[OH:10])[CH:5]=[O:6].C(=O)([O-])[O-].[Cs+].[Cs+].Br[CH2:19][CH2:20]Br>CN(C)C=O>[Br:1][C:2]1[C:9]2[O:10][CH2:19][CH2:20][O:11][C:8]=2[CH:7]=[C:4]([CH:5]=[O:6])[CH:3]=1

Participants

5

Reactant 3

HCID 78391,2-DibromoethaneHCID 10796Cesium carbonateHCID 854055-Bromo-3,4-dihydroxybenzaldehyde

Product 1

HCID 166371768-Bromo-2,3-dihydro-1,4-benzodioxine-6-carbaldehydeYield 75%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 3-bromo-4,5-dihydroxybenzaldehyde (11.5 g, 0.52 mol) in dimethylformamide (220 ml) was added cesium carbonate (50.7 g, 1.56 mol). The mixture was stirred at ambient temperature for 30 min, then 1,2-dibromoethane (12.76 g, 0.68 mol) were added. After heating at 80° for 4 h, the dimethylformamide was removed under reduced pressure. The residue was partitioned between water and ethyl acetate, and the organic layer was washed with brine and dried. The crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate) to give the desired compound as an off-white solid (9.57 g, 75%).

Workup

  1. temperatureAfter heating at 80° for 4 h
  2. customthe dimethylformamide was removed under reduced pressure
  3. customThe residue was partitioned between water and ethyl acetate
  4. washthe organic layer was washed with brine
  5. customdried
  6. customThe crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate)

Sources & evidence

ORD record
ord-1485c067dc3942858e5d7f74b0bdc26e
Source dataset
uspto-grants-2010_06
Patent number
US07732461B2

Linked notes

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