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

HRID 973273Notes

Reaction equation

HRID 973273 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.C([O-])(=O)C.[Pb+4].C1(C)C=CC=CC=1>C(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

6

Reactant 4

HCID 176Acetic AcidHCID 1140TolueneHCID 867332766,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl esterHCID 178418268HCID 178418268, compound

Product 1

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

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

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 tetraccetate was refluxed in 30 parts of glacial acetic acid for 6.5 hours. A further 9.9 parts of lead tetracetate 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 chromotographed 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. washfor elution

Sources & evidence

ORD record
ord-1296afe4f5f445e7909253b89299ee2e
Source dataset
uspto-grants-1977_10
Patent number
US04055654

Reaction notes

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