PREPARATION OF 3,4-DIHYDRO-2-METHYL-4-OXO-2H-1,2-BENZOTHIAZINE-3-CARBOXYLIC ACID-1,1-DIOXIDE,AND ITS USE AS AN INTERMEDIATE IN THE PREPARATION OF THE CORRESPONDING N-(2-PYRIDYL)-AND N-(2-THIAZOLYL)CARBOXAMIDES

摘要

Process for production of 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide by hydrolysis, in the presence of hydroxide ions, of an alkyl or aralkyl ester thereof followed by precipitation of the acid at pH below 6.0 and its use as an intermediate for the production of N-(2-pyridyl)-3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carbox amide-1,1-dioxide and the analogous N-(2-thiazolyl)-compound, effective antiinflammatory agents.