Thioglycolic Acid → 5-Fluoro-1-benzothiophene-2-carboxylic acid

In a glass pressure bottle, 2,5-difluorobenzaldehyde (11 ml, 0.1 mol) was added to a solution of 2-mercaptoacetic acid (9 ml) in potassium hydroxide (16.5 g) and water (155 ml). The bottle was then sealed and heated in a hot oil bath to 125±5° C. for 1.25 hours. The bottle was then removed from the hot oil bath and cooled. A pale yellow precipitate was obtained in the bottle. At ambient temperature, the bottle was opened and sufficient water was added to dissolve the precipitate. The resultant aqueous material was washed with ether and then acidified with hydrochloric acid to produce a pale yellow solid. The pale yellow solid was collected on a filter, washed with water and dried, to produce 15.5 g of 5-fluoro-2-benzo-[b]thiophenecarboxylic acid (80.1% yield, mp>300° C.).

1. customThe bottle was then sealed
2. customThe bottle was then removed from the hot oil bath
3. temperaturecooled
4. customA pale yellow precipitate was obtained in the bottle
5. customAt ambient temperature
6. dissolutionto dissolve the precipitate
7. washThe resultant aqueous material was washed with ether
8. customto produce a pale yellow solid
9. customThe pale yellow solid was collected on a filter
10. washwashed with water
11. customdried

ORD record

ord-8597088b936b4e00b8463565dad44c73

Source dataset

uspto-grants-1999_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05965749