Synthesis and Biological Properties of {[(4-Hydroxy-1-Methyl-2,2-Dioxido-1 H -2,1-Benzothiazin-3-YL)Carbonyl]Amino}-Benzoic Acids and Their Derivatives

Continuing the search for novel biologically active substances among the 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides series, we report here the synthesis of a series of {[(4-hydroxy-1-methyl-2,2-dioxido-1H-2,1-benzothiazin-3-yl)carbonyl]amino} benzoic acids asd their derivatives at the carboxyl group. Pharmacological testing showed that compounds with a free carboxyl group are of interest as potential diuretics, while carbamide derivatives have potential as analgesics. Esterification of the carboxyl group with lower alkyl alcohols was less effective.