Phosphorus oxychloride → (1,2-Benzoxazol-3-yl)methanesulfonyl chloride
Reaction equation
[O:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[C:3]([CH2:10][S:11]([OH:14])(=O)=[O:12])=[N:2]1.P(Cl)(Cl)([Cl:17])=O>>[CH:8]1[CH:9]=[C:4]2[C:3]([CH2:10][S:11]([Cl:17])(=[O:14])=[O:12])=[N:2][O:1][C:5]2=[CH:6][CH:7]=1Participants
3
Procedure
1,2-Benzisoxazole-3-methanesulfonic acid (1) (1.00 g, 4.7 mmol) was mixed with xylenes (10 mL) and phosphorous oxychloride (1.0 mL, 11 mmol) and heated to reflux until the reaction was complete. The mixture was filtered through CELITE™ and evaporated to dryness to yield 1,2-benzisoxazole-3-methanesulfonyl chloride (2) as a light brown solid. It was dissolved in ethyl acetate (10 mL), cooled in an ice-bath and treated with ammonia. Work-up analogous to example 2 gave pure zonisamide.
Workup
- temperatureheated
- temperatureto reflux until the reaction
- filtrationThe mixture was filtered through CELITE™
- customevaporated to dryness