Potassium Hydroxide → 5-(4-Hydroxyphenyl)-2-benzofurancarboxylic acid

A mixture of 10.4 g of 11 and 7.2 g of potassium hydroxide in 170 ml of ethanol was refluxed for 2 hours. The solvent was evaporated under reduced pressure. The residue was mixed with 200 ml of water, and the mixture was acidified to pH=2 with concentrated hydrochloric acid, stirred for 30 minutes and filtered. The solid was washed with water, dried under reduced pressure and mixed with tetrahydrofuran. The mixture was refluxed and filtered. The filtrate was concentrated, the residue was washed with ether and mixed with tetrahydrofuran. The mixture was filtered, the filtrate was concentrated to about one-fourth its volume and triturated with ether. The resulting solid was collected and dried under reduced pressure to give 16, mp: 297°-300° C.

1. temperaturewas refluxed for 2 hours
2. customThe solvent was evaporated under reduced pressure
3. additionThe residue was mixed with 200 ml of water
4. filtrationfiltered
5. washThe solid was washed with water
6. customdried under reduced pressure
7. additionmixed with tetrahydrofuran
8. temperatureThe mixture was refluxed
9. filtrationfiltered
10. concentrationThe filtrate was concentrated
11. washthe residue was washed with ether
12. additionmixed with tetrahydrofuran
13. filtrationThe mixture was filtered
14. concentrationthe filtrate was concentrated to about one-fourth its volume
15. customtriturated with ether
16. customThe resulting solid was collected
17. customdried under reduced pressure

ORD record

ord-63e2892eac4e41e6ba97fd3515c48342

Source dataset

uspto-grants-1980_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04213998