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

Participants

Reaction Conditions

Reaction Steps

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%.

Provenance & Evidence