6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester → 6,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

HRID 1606328Notes

Reaction equation

HRID 1606328 reaction equation
[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:24])([CH3:23])[CH3:22])[C:8]2[O:13][CH:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH2:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2].C([O-])(=O)C.C([O-])(=O)C.C([O-])(=O)C.C([O-])(=O)C.[Pb+4]>C(O)(=O)C>[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:22])([CH3:24])[CH3:23])[C:8]2[O:13][C:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2]

Participants

4

Reactant 2

HCID 867332766,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl esterHCID 178418268HCID 178418268, compound2×

Product 1

HCID 538439426,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 3.32 parts of 6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester and 9.9 parts of lead tetraacetate was refluxed in 30 parts of glacial acetic acid for 6.5 hours. A further 9.9 parts of lead tetraacetate were added and the reflux was continued for another 3.25 hours. After cooling, the reaction mixture was extracted with ether. The ether extract was washed with sodium bicarbonate solution and water and was dried. Evaporation of the ether gave an oil which was chromatographed on silica gel using a 9:1 mixture of toluene and ethanol for elution. This yielded 0.23 parts of 6,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester, m.p. 130°-131.5°C (after crystallisation from light petroleum (b.p. 40°-60°C). This product was shown by spectral means to be the same as that of Example 13.

Workup

  1. temperatureAfter cooling
  2. extractionthe reaction mixture was extracted with ether
  3. extractionThe ether extract
  4. washwas washed with sodium bicarbonate solution and water
  5. customwas dried
  6. customEvaporation of the ether
  7. customgave an oil which
  8. customwas chromatographed on silica gel using
  9. additiona 9:1 mixture of toluene and ethanol
  10. washfor elution

Sources & evidence

ORD record
ord-c214b0f78bb34397877a9249d0282c56
Source dataset
uspto-grants-1976_04
Patent number
US03952104

Reaction notes

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