Water → 6-(2-Bromo-ethoxy)-chromen-2-one

HRID 1416947Notes

Reaction equation

HRID 1416947 reaction equation
[OH:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7](=[O:12])[CH:6]=[CH:5]2.[Br:13][CH2:14][CH2:15]Br.C(=O)([O-])[O-].[K+].[K+].O>CC(C)=O.C(OCC)(=O)C>[Br:13][CH2:14][CH2:15][O:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7](=[O:12])[CH:6]=[CH:5]2

Participants

7

Reactant 4

HCID 962WaterHCID 78391,2-DibromoethaneHCID 11430Potassium CarbonateHCID 994776-hydroxy-2H-chromen-2-one

Product 1

HCID 154622996-(2-Bromo-ethoxy)-chromen-2-oneYield 26%

Reagents, catalysts & solvents 2

HCID 180AcetoneSolventHCID 8857Ethyl AcetateSolvent

Procedure

A mixture of 6-hydroxy-chromene-2-one, which can be synthesized in accordance with the procedure set forth by T. Harayama, K. Katsuno, H. Nishioka, M. Fujii, Y. Nishita, H. Ishii, and Y. Kaneko, Heterocycles, 1994;39:613, (3.2 g, 19.7 mmol), 1,2-dibromoethane (6.7 mL, 14.6 g, 78 mmol), and potassium carbonate (5.4 g, 39 mmol) in 150 mL of acetone is stirred at reflux for 48 hours. The cooled reaction mixture is added to 1.0 L of water and 250 mL of ethyl acetate. The mixture is filtered, and the insoluble material is washed with a small amount of additional ethyl acetate. The combined filtrates are separated, and the aqueous layer is washed several times with fresh ethyl acetate. The combined organic layers are washed with 5% aqueous sodium carbonate solution and brine, then dried (sodium sulfate), and evaporated. The residue is purified by flash chromatography (1% methanol in dichloromethane elution) to give 1.4 g (26%) of product. A sample recrystallized from ethyl acetate-hexane had melting point (mp) 101-102° C.

Workup

  1. customcan be synthesized in accordance with the procedure
  2. temperatureat reflux for 48 hours
  3. customThe cooled reaction mixture
  4. filtrationThe mixture is filtered
  5. washthe insoluble material is washed with a small amount of additional ethyl acetate
  6. customThe combined filtrates are separated
  7. washthe aqueous layer is washed several times with fresh ethyl acetate
  8. washThe combined organic layers are washed with 5% aqueous sodium carbonate solution and brine
  9. dry with materialdried (sodium sulfate)
  10. customevaporated
  11. customThe residue is purified by flash chromatography (1% methanol in dichloromethane elution)

Sources & evidence

ORD record
ord-84f15846de6049e2b5b726c0e72c9b52
Source dataset
uspto-grants-1999_06
Patent number
US05916914

Reaction notes

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