6-Chloro-3-alkylamino-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide derivatives potently and selectively activate atp sensitive potassium channels of pancreatic β-cells

6-Chloro-3-alkylamino-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide derivatives were synthesized and characterized as activators of adenosine 5‘-triphosphate (ATP) sensitive potassium (KATP) channels in the β-cells by measuring effects on membrane potential and insulin release in vitro. The effects on vascular tissue in vitro were measured on rat aorta and small mesenteric vessels. Selected compounds were characterized as competitive inhibitors of [3H]glibenclamide binding to membranes of HEK293 cells expressing human SUR1/Kir6.2 and as potent inhibitors of insulin release in isolated rat islets. 6-Chloro-3-(1-methylcyclobutyl)amino-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide (54) was found to bind and activate the SUR1/Kir6.2 KATP channels in the low nanomolar range and to be at least 1000 times more potent than the reference compound diazoxide with respect to inhibition of insulin release from rat islets. Several compounds, e.g., 3-propylamino- (30), 3-isopropylamino- (34), 3-(S)-sec-butylamino- (37...