Hydrochloric Acid → 2-Amino-3-fluorobenzoic acid

Temperature

70 °C

A mixture of 19.27 g of the product of Step B and 197 ml of 10N sodium hydroxide solution was heated to 70° C. with stirring and heating was ceased to add 36.5 ml of 30% hydrogen peroxide over 20 minutes during which the temperature rose to 80° C. and descended to 70° C. At the end of the addition, the mixture was heated to 80° C. and held there for 10 minutes and then was cooled during which a mass formed. The latter was added to 200 ml of water with stirring and the pH was adjusted to 1 by addition of concentrated hydrochloric acid at a temperature less than 20° C. The mixture was stirred for 90 minutes and was vacuum filtered. The product was empasted twice with iced water and dried under reduced pressure at 70° C. The product was crystallized from 100 ml of a 1-1 ethanol-water mixture and 3 ml of acetic acid. The mixture was iced for one hour and was vacuum filtered. The product was empasted with a 1-1 ethanol-water mixture and dried at 70° C. under reduced pressure to obtain 14.8 g of 2-amino-3-fluoro-benzoic acid melting at 188° C.

1. temperatureheating
2. customrose to 80° C.
3. customdescended to 70° C
4. additionAt the end of the addition
5. temperaturethe mixture was heated to 80° C.
6. temperaturewas cooled during which a mass
7. customformed
8. stirringwith stirring
9. stirringThe mixture was stirred for 90 minutes
10. filtrationfiltered
11. customdried under reduced pressure at 70° C
12. customThe product was crystallized from 100 ml of a 1-1 ethanol-water mixture and 3 ml of acetic acid
13. waitThe mixture was iced for one hour
14. filtrationfiltered
15. customdried at 70° C. under reduced pressure

ORD record

ord-38f156c34e6040289ff3047bd5f8975b

Source dataset

uspto-grants-1988_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04736033