| abstract |
The invention relates to a method for the production of 3-isopropyl-1H-2,1,3-benzothiazine-4(3H)-one-2,2-dioxide (I) or its salt. The method is characterized in that anthranilic acid isopropylamide (II) is reacted simultaneously with sulphur trioxide or chlorosulphonic acid in the presence of an organic base, or with sulphur trioxide adducts on organic bases, and phosphoroxychloride at 50 DEG C until reflux temperature, and then optionally transformed into their salts. |