Hydrochloric Acid → 7-Methoxy-1-benzofuran-2-carboxylic acid

HRID 1978773Notes

Reaction equation

HRID 1978773 reaction equation
O=[CH:2][C:3]1[CH:11]=[CH:10][CH:9]=[C:6]([O:7][CH3:8])[C:4]=1[OH:5].C(=O)([O-])[O-].[K+].[K+].Br[CH:19](C(OCC)=O)[C:20]([O:22]CC)=[O:21].Cl>CC(=O)CC>[CH3:8][O:7][C:6]1[C:4]2[O:5][C:19]([C:20]([OH:22])=[O:21])=[CH:2][C:3]=2[CH:11]=[CH:10][CH:9]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8991o-VanillinHCID 11430Potassium CarbonateHCID 69637Diethyl bromomalonate

Product 1

HCID 6060377-Methoxy-1-benzofuran-2-carboxylic acidYield 37.4%

Reagents, catalysts & solvents 1

HCID 6569Methyl Ethyl KetoneSolvent

Procedure

To a suspension of o-vanillin (25.0 g) and potassium carbonate (28.4 g) in 2-butanone (10 ml) was added diethyl bromomalonate (49.1 g), and the mixture was refluxed under nitrogen atmosphere for 7 hours and cooled. To the mixture was added 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried with magnesium sulfate. Under reduced pressure, the solvent was evaporated, and the resulting red oil was suspended in a solution of potassium hydroxide (17.5 g) in ethanol (175 ml). The suspension was refluxed for 2 hours and cooled, and to the mixture was added water. The mixture was made acidic with 1N hydrochloric acid and extracted with ethyl acetate (twice). The organic layer was washed with water and saturated brine, and dried with magnesium sulfate. Under reduced pressure, the solvent was evaporated to give yellow solid of 7-methoxybenzofuran-2-carboxylic acid (11.8 g).

Workup

  1. temperaturethe mixture was refluxed under nitrogen atmosphere for 7 hours
  2. temperaturecooled
  3. extractionthe mixture was extracted with ethyl acetate
  4. washThe organic layer was washed with saturated brine
  5. dry with materialdried with magnesium sulfate
  6. customUnder reduced pressure, the solvent was evaporated
  7. temperatureThe suspension was refluxed for 2 hours
  8. temperaturecooled
  9. additionto the mixture was added water
  10. extractionextracted with ethyl acetate (twice)
  11. washThe organic layer was washed with water and saturated brine
  12. dry with materialdried with magnesium sulfate
  13. customUnder reduced pressure, the solvent was evaporated

Sources & evidence

ORD record
ord-1f208f51eb69474392091824e1b94a77
Source dataset
uspto-grants-2001_05
Patent number
US06235771B1

Reaction notes

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