Acrolein → 2H-1-Benzopyran-3-carboxaldehyde, 6-bromo-

HRID 466182Notes

Reaction equation

HRID 466182 reaction equation
[Br:1][C:2]1[CH:9]=[C:6]([CH:7]=O)[C:5]([OH:10])=[CH:4][CH:3]=1.C(=O)([O-])[O-].[K+].[K+].[CH:17]([CH:19]=[CH2:20])=[O:18]>O1CCOCC1>[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:20][C:19]([CH:17]=[O:18])=[CH:7][C:6]=2[CH:9]=1

Participants

5

Reactant 3

HCID 7847AcroleinHCID 11430Potassium CarbonateHCID 728635-Bromosalicylaldehyde

Product 1

HCID 424272H-1-Benzopyran-3-carboxaldehyde, 6-bromo-

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

The starting material is prepared as follows: A mixture of 5-bromosalicylaldehyde (10.3 g, 51.1 mmol) and potassium carbonate (7.0 g, 51.1 mmol) in 30 ml of 1,4-dioxane is treated with acrolein (4.3 g, 76.6 mmol). The mixture is heated at reflux for 2 hours and allowed to cool. This is partitioned between ether and water, and separated. The aqueous layer is extracted once with ether, and the organic phases are combined, dried (MgSO4) and evaporated. Flash chromatography (silica gel, 8% ethyl acetate/hexane) yields 6-bromo-2H-1-benzopyran-3-carboxaldehyde, m.p. 103°-104° C., which is converted to the final product as described above.

Workup

  1. customThe starting material is prepared
  2. temperatureThe mixture is heated
  3. temperatureat reflux for 2 hours
  4. temperatureto cool
  5. customThis is partitioned between ether and water
  6. customseparated
  7. extractionThe aqueous layer is extracted once with ether
  8. dry with materialdried (MgSO4)
  9. customevaporated

Sources & evidence

ORD record
ord-8861b9acb8b44147b5eb8ce4a81fafe2
Source dataset
uspto-grants-1992_10
Patent number
US05155130

Reaction notes

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