Patent ID: 6900333

Claim:
A process for the preparation of crystals of 1,2-benzisoxazole-3-methanesulfonamide containing residual 1,2-dichloroethane of not more than 5 ppm, which comprises adding an aqueous C 2-4 alcohol to crystals of 1,2-benzisoxazole-3-methanesulfonamide containing residual 1,2-dichloroethane of more than 5 ppm, removing said 1,2-dichloroethane by azeotropic distillation to obtain a residual mixture, followed by collecting precipitated crystals of 1,2-benzisoxazole-3-methanesulfonamide containing not more than 5 ppm of 1,2-dichloroethane from the residual mixture.