Potassium Hydroxide → 4-Methyl-1-oxo-1H-2-benzopyran-3-carboxylic acid

HRID 1283596Notes

Reaction equation

HRID 1283596 reaction equation
[C:1]([C:4]1[CH:12]=[CH:11][CH:10]=[CH:9][C:5]=1[C:6]([OH:8])=[O:7])(=O)[CH3:2].Br[CH:14](C(OCC)=O)[C:15]([O:17]CC)=[O:16].[OH-].[K+]>C(O)C>[CH3:2][C:1]1[C:4]2[C:5](=[CH:9][CH:10]=[CH:11][CH:12]=2)[C:6](=[O:7])[O:8][C:14]=1[C:15]([OH:17])=[O:16]

Participants

5

Reactant 3

HCID 14797Potassium HydroxideHCID 684742-Acetylbenzoic acidHCID 69637Diethyl bromomalonate

Product 1

HCID 123882954-Methyl-1-oxo-1H-2-benzopyran-3-carboxylic acid

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 2-acetylbenzoic acid (6.21g), diethyl bromomalonate (9.0g.) and potassium hydroxide (2.12g.) in ethanol (50ml.) was heated under reflux for 6 hours. The cooled mixture was evaporated to dryness, water (100ml.) added and extracted with ether. The combined ethereal extracts were washed with water, dried and evaporated to dryness. The residue was heated under reflux with a mixture of concentrated hydrochloric acid (160ml.) -- acetic acid (100ml.) for two hours, cooled and poured into iced water (1 litre). Filtration gave the product as a white solid, mp. 250°-2°, (lit mp. 248°-9°) (Found: C, 64.59; H, 4.01. C11H8O4 requires C, 64.70; H, 3.95).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 6 hours
  3. customThe cooled mixture was evaporated to dryness, water (100ml.)
  4. additionadded
  5. extractionextracted with ether
  6. washThe combined ethereal extracts were washed with water
  7. customdried
  8. customevaporated to dryness
  9. temperatureThe residue was heated
  10. temperatureunder reflux with a mixture of concentrated hydrochloric acid (160ml.)
  11. temperaturecooled
  12. additionpoured into iced water (1 litre)
  13. filtrationFiltration

Sources & evidence

ORD record
ord-e817eef605554407a79538ee2289fed7
Source dataset
uspto-grants-1976_08
Patent number
US03975535

Reaction notes

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