Acetonitrile → 1,2-Benzoxazol-3-ylmethanesulfonimidic acid

Temperature

65 °C

1,2-Benzisoxazole-3-methanesulfonic acid (1) (20.0 g, 93.8 mmol) was mixed with acetonitrile (60 mL) and heated to reflux. The clear solution was cooled to 65° C. and phosphorous oxychloride (5.7 mL; 62.3 mmol) was added. The mixture was heated to reflux for 10 hours and then cooled to room temperature. Ethyl acetate (100 mL) was added and the mixture was filtered through CELITE™, which was subsequently washed with ethyl acetate (40 mL). The filtrate was cooled in an ice bath and ammonia gas was bubbled through the solution for 1 hour. The mixture was concentrated and water (100 mL) was added. The mixture was heated to reflux and cooled. It was concentrated, cooled in an ice-bath and filtered to yield crude zonisamide. Purification was achieved by recrystallization from iso-propanol/water. The yield of purified product was 78.8%.

1. temperatureheated to reflux
2. temperatureThe mixture was heated
3. temperatureto reflux for 10 hours
4. temperaturecooled to room temperature
5. filtrationthe mixture was filtered through CELITE™, which
6. washwas subsequently washed with ethyl acetate (40 mL)
7. temperatureThe filtrate was cooled in an ice bath
8. customammonia gas was bubbled through the solution for 1 hour
9. concentrationThe mixture was concentrated
10. additionwater (100 mL) was added
11. temperatureThe mixture was heated
12. temperatureto reflux
13. temperaturecooled
14. concentrationIt was concentrated
15. temperaturecooled in an ice-bath
16. filtrationfiltered

ORD record

ord-9f1f208744f14ca49caead027988a965

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07375233B2