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-carboxamid e-1,1-dioxide and the analogous N-(2-thiazolyl)-compound, effective antiinflammatory agents.
A process for the synthesis of N-aryl-3,4-dihydro-2-alkyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides by treatment of N-aryl-N'-alkyl-N'-(2'-alkoxycarbonylbenzenesulfonyl)glycineamides, useful intermediates for said process, with an alkali or alkaline earth metal hydride in a reaction-inert solvent at 50.degree.-150.degree.C., said products being antiinflammatory agents.