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

HRID 973271Notes

Reaction equation

HRID 973271 reaction equation
[C:1]([C:5]1[CH:19]=[C:18]([C:20]([CH3:23])([CH3:22])[CH3:21])[CH:17]=[CH:16][C:6]=1[O:7][CH:8]([CH2:12][C:13](O)=[O:14])[C:9]([OH:11])=[O:10])([CH3:4])([CH3:3])[CH3:2].S(=O)(=O)(O)O.C(=O)(O)[O-].[Na+].[CH2:34](O)[CH3:35]>O>[C:20]([C:18]1[CH:19]=[C:5]([C:1]([CH3:4])([CH3:3])[CH3:2])[C:6]2[O:7][CH:8]([C:9]([O:11][CH2:34][CH3:35])=[O:10])[CH2:12][C:13](=[O:14])[C:16]=2[CH:17]=1)([CH3:23])([CH3:21])[CH3:22]

Participants

6

Reactant 4

HCID 702EthanolHCID 1118Sulfuric AcidHCID 516892Sodium BicarbonateHCID 214026122,4-Di-t-butylphenoxysuccinic acid

Product 1

HCID 867332766,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

A mixture of 50 parts of 2,4-di-t-butylphenoxysuccinic acid and 100 parts of concentrated sulphuric acid was stirred at room temperature for three hours. The resulting solution was poured into water, excess sodium bicarbonate solution was added and the basic solution was extracted with ether. The aqueous extract was acidified with concentrated hydrochloric acid and the product was extracted into ether. The ether extract yielded a residue which was esterified by refluxing for three hours with 200 parts of a 3% v/v solution of ethanol containing concentrated sulphuric acid. After cooling, water was added and the esterified product was extracted into ether. The ether extract was washed with sodium bicarbonate solution and water, dried and the ether was removed by evaporation. Chromatography of the resulting residue on silica gel, elutingwith a 3:2 mixture of chloroform and light petroleum (b.p. 40°-60° C), gave 1 part of 6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester as a semi-solid.

Workup

  1. additionwas added
  2. extractionthe basic solution was extracted with ether
  3. extractionThe aqueous extract
  4. extractionthe product was extracted into ether
  5. extractionThe ether extract
  6. customyielded a residue which
  7. temperatureAfter cooling
  8. extractionthe esterified product was extracted into ether
  9. extractionThe ether extract
  10. washwas washed with sodium bicarbonate solution and water
  11. customdried
  12. customthe ether was removed by evaporation
  13. additionChromatography of the resulting residue on silica gel, elutingwith a 3:2 mixture of chloroform and light petroleum (b.p. 40°-60° C)

Sources & evidence

ORD record
ord-8e76fdc349d440d686428fa5b308c880
Source dataset
uspto-grants-1977_10
Patent number
US04055654

Reaction notes

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