FOERFARANDE FOER FRAMSTAELLNING AV 4-HYDROXI-3-(5-METYL-3-ISOXAZOLYLKARBAMOYL)-2-METYL-2H-1,2-BENSOTIAZIN-1,1-DIOXID SAMT VID FOERFARANDET ANVAENDBARA MELLANPRODUKTER

A process for the preparation of 4-hydroxy-3- (5-methyl-3-isoxazolyl-carbamoyl) -2-methyl-2H-1,2-benzothiazine 1,1-dioxide of the formula i ** (see formula) ** Characterized in that in its embodiment it comprises the following steps: A) reacting 3-amino-5-methylisoxazole (II) with a haloacetyl halide to form compound iii ** (see formula) ** B) reacting said compound iii with a saccharin salt to form compound iv: ** (see formula) ** C) reacting the above compound iv with an alkali metal alkoxide of a lower alcohol in an inert solvent at a controlled temperature followed by acidification to form the compound v: ** (see formula) ** D) methylating the above-formed compound v by reaction at controlled temperature, with a methylating agent in aqueous inert solvent containing excess base, followed by acidification to obtain compound vi: ** (see formula) ** And finally E) heating the above compound vi with an organic base in an inert solvent to obtain a desired compound i. (Machine-translation by Google Translate, not legally binding)