Phthalaldehydic acid → 1-oxo-1H-isochromene-3-carboxylic acid

HRID 259252Notes

Reaction equation

HRID 259252 reaction equation
[C:1]([C:4]1[CH:11]=[CH:10][CH:9]=[CH:8][C:5]=1[CH:6]=O)([OH:3])=[O:2].Br[CH:13](C(OCC)=O)[C:14]([O:16]CC)=[O:15].C(=O)([O-])[O-].[K+].[K+]>C(C(C)=O)C>[C:1]1([C:4]2[C:5](=[CH:8][CH:9]=[CH:10][CH:11]=2)[CH:6]=[C:13]([C:14]([OH:16])=[O:15])[O:3]1)=[O:2]

Participants

5

Reactant 3

HCID 8406Phthalaldehydic acidHCID 11430Potassium CarbonateHCID 69637Diethyl bromomalonate

Product 1

HCID 3455611-oxo-1H-isochromene-3-carboxylic acid

Reagents, catalysts & solvents 1

HCID 6569Methyl Ethyl KetoneSolvent

Procedure

A mixture of 2- carboxybenzaldehyde (20.0g), diethyl bromomalonate (20.0g) and anhydrous potassium carbonate (20.0g) in ethyl methylketone (200ml.) was heated under reflux, with stirring, for 5 hours. The cooled mixture was evaporated to dryness and water (300ml.) added to the residue. After extraction with a mixture of ether-chloroform, the organic extracts were washed with water, dried and evaporated to dryness. The residual solid was heated under reflux with a mixture of concentrated hydrochloric acid (360ml.) -- acetic acid (240ml.) for 2 hours. After cooling, the mixture was poured into iced water (1,200ml.). Filtration gave the product as a white solid, m.p. 241°-2° (lit mp. 239-240°), (Found: C, 62.87; H, 3.39. C10H6O4 requires C, 63.16; H 3.18).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux
  3. customThe cooled mixture was evaporated to dryness and water (300ml.)
  4. additionadded to the residue
  5. extractionAfter extraction
  6. additionwith a mixture of ether-chloroform
  7. washthe organic extracts were washed with water
  8. customdried
  9. customevaporated to dryness
  10. temperatureThe residual solid was heated
  11. temperatureunder reflux with a mixture of concentrated hydrochloric acid (360ml.)
  12. waitacetic acid (240ml.) for 2 hours
  13. temperatureAfter cooling
  14. additionthe mixture was poured into iced water (1,200ml.)
  15. filtrationFiltration

Sources & evidence

ORD record
ord-201fefbd76214ed9a17f4d005d953b7a
Source dataset
uspto-grants-1977_07
Patent number
US04036964

Reaction notes

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