Synthesis and biological effects of new 3-alkylamino-4H-1,2,4- benzothiadiazine 1,1-dioxides on insulin-secreting cells

3-Alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides with nitro, amino or acetylamino groups in the 7-position have been synthesized in an attempt to discover new tissue-selective K(ATP)-channel openers. The compounds were tested as putative pancreatic β-cells K(ATP)-channel openers by measuring their inhibitory activity on the insulin releasing process. The influence of the substituent in the 7-position on the acidic character (pK(a)) and on biological activity is discussed. The nitrobenzene derivatives were biologically active, but less so than the un-derivatized parent pyridothiadiazine dioxides.