Malonic Acid → 8-Ethyl-4-hydroxy-2H-1-benzopyran-2-one

HRID 1272260Notes

Reaction equation

HRID 1272260 reaction equation
[CH2:1]([C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[OH:9])[CH3:2].[C:10](O)(=[O:15])[CH2:11][C:12](O)=[O:13].P(Cl)(Cl)(Cl)=O.C(=O)([O-])[O-].[Na+].[Na+]>[Cl-].[Zn+2].[Cl-].O>[CH2:1]([C:3]1[CH:8]=[CH:7][CH:6]=[C:5]2[C:4]=1[O:9][C:12](=[O:13])[CH:11]=[C:10]2[OH:15])[CH3:2]

Participants

7

Reactant 4

HCID 867Malonic AcidHCID 69972-EthylphenolHCID 10340Sodium CarbonateHCID 24813Phosphorus oxychloride

Product 1

HCID 547077918-Ethyl-4-hydroxy-2H-1-benzopyran-2-oneYield 24.1%

Reagents, catalysts & solvents 2

HCID 3007855ZincchlorideCatalystHCID 962WaterSolvent

Procedure

A mixture of 2-ethylphenol (Aldrich) (6.1 g; 50 mmole), malonic acid (Aldrich) (5.2 g; 50 mmole), zinc chloride (20.4 g, 150 mmole) and phosphorous oxychloride (Merck) (14 mL; 150 mmole) was heated under stirring for 24 hours at 70–75° C., whereupon the reaction was stopped and a mixture of water and ice was added. The reaction mixture was stirred for further 2 hours at room temperature and then 10% sodium carbonate (150 mL) was added to the filtered brown precipitate while stirring. The insoluble part was filtered and the filtrate was acidified with concentrated hydrochloric acid, whereat a brown precipitate was precipitated, which was then filtered and washed with cold water. By recrystallization from 50% ethanol there were obtained 2.29 g (24%) of brown powdery 8-ethyl-4-hydroxycoumarin.

Workup

  1. temperaturewas heated
  2. additionwas added
  3. stirringThe reaction mixture was stirred for further 2 hours at room temperature
  4. stirringwhile stirring
  5. filtrationThe insoluble part was filtered
  6. customwas precipitated
  7. filtrationwhich was then filtered
  8. washwashed with cold water
  9. customBy recrystallization from 50% ethanol

Sources & evidence

ORD record
ord-0f673c9790ca4d0caf171f9adcfa9d61
Source dataset
uspto-grants-2007_04
Patent number
US07208518B2

Reaction notes

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