Ethyl Acetate → Tert-butyl 6-bromo-2H-chromene-3-carboxylate

HRID 1277187Notes

Reaction equation

HRID 1277187 reaction equation
[Br:1][C:2]1[CH:9]=[C:6]([CH:7]=O)[C:5]([OH:10])=[CH:4][CH:3]=1.[C:11]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])(=[O:14])[CH:12]=[CH2:13].CC(C)([O-])C.[K+].C(OCC)(=O)C>C(O)(C)(C)C>[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:13][C:12]([C:11]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])=[CH:7][C:6]=2[CH:9]=1

Participants

6

Reactant 4

HCID 8857Ethyl AcetateHCID 15458tert-Butyl acrylateHCID 728635-BromosalicylaldehydeHCID 23665647Potassium tert-butoxide

Product 1

HCID 10566979Tert-butyl 6-bromo-2H-chromene-3-carboxylate

Reagents, catalysts & solvents 1

HCID 6386tert-ButanolSolvent

Procedure

To a solution of 5-bromosalicylaldehyde (10.0 g) and tert-butyl acrylate (17.5 ml) in tert-butanol (100 ml) was added potassium tert-butoxide (1.67 g) at room temperature, and the mixture was refluxed for 66 hours and cooled to room temperature. To the mixture was added ethyl acetate, and the mixture was washed with water, 1N sodium hydroxide and saturated sodium chloride solution, dried with magnesium sulfate and concentrated. The residue was separated and purified with column chromatography (ethyl acetate/hexane=1:19) to give tert-butyl 6-bromo-2H-1-benzopyran-3-carboxylate (10.86 g) as pale yellow crystals.

Workup

  1. temperaturethe mixture was refluxed for 66 hours
  2. washthe mixture was washed with water, 1N sodium hydroxide and saturated sodium chloride solution
  3. dry with materialdried with magnesium sulfate
  4. concentrationconcentrated
  5. customThe residue was separated
  6. custompurified with column chromatography (ethyl acetate/hexane=1:19)

Sources & evidence

ORD record
ord-54ca61cd09a74cc0a9f5734447714415
Source dataset
uspto-grants-2000_12
Patent number
US06166006

Reaction notes

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