PROCESS FOR MAKING PHARMACEUTICALLY USABLE 2-METHYL-4-CARBOXY-4-MEZYLOXY-2H-1,2-BENZOTHIAZINE-1,1-DIOXIDE-3-N,N-DIMETHYLACETAMID SOLVATES

摘要

This invention relates to a method for the preparation of a pharmaceutically usable 2-methyl-4-hydroxy-2H-1,2-benzothiazine-1,1-dioxide with formula I IMG I In accordance with the invention 2-methyl-4-mesyloxy-2H,1,2-benzothiazine-1,1-dioxide-3-carboxylic acid with formula II IMG II is reacted with 2-aminopyridine in the presence of thionyl chloride in an inert solvent. The invention relates also to the intermediate with formula II which can be used in the method.