Hydrochloric Acid → 6-Methoxy-1-benzofuran-2-carboxylic acid

To a suspension of 2-hydroxy-4-methoxybenzaldehyde (20.0 g) and potassium carbonate (20.0 g) in2-butanone (80 ml) was added diethyl bromomalonate (39.3 g), and the mixture was refluxed under nitrogen atmosphere for 7 hours and cooled. To the mixture was added water, and the mixture was made acidic with 1N hydrochloric acid and 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 dark brown oil was suspended in a solution of potassium hydroxide (20.0 g) in ethanol (200 ml). The suspension was refluxed for 1 hour and cooled, and to the mixture was added water. The mixture was made acidic with 1N hydrochloric acid and extracted with ethylacetate(twice). The organic layer was washed with water and saturated brine, and dried with magnesium sulfate. Under reduced pressure, the solvent was evaporated, and the resulting solid was washed with hexane to give yellow solid of 6-methoxybenzofuran-2-carboxylic acid (11.8 g).

1. temperaturethe mixture was refluxed under nitrogen atmosphere for 7 hours
2. temperaturecooled
3. extractionextracted 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 1 hour
8. temperaturecooled
9. additionto the mixture was added water
10. extractionextracted with ethylacetate(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
14. washthe resulting solid was washed with hexane

ORD record

ord-79f5bae4553c4b91b1499b809ee56d04

Source dataset

uspto-grants-2001_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06235771B1