2-[(2-Pyridylmethyl) sulfinyl] thienoimidazoles were synthesized and investigated as potential inhibitors of gastric H+/K+-ATPase. The [3, 4-d] isomers of the two possible thienoimidazole series were found to be potent inhibitors of gastric acid secretion in vitro and in vivo. Structure-activity relationships indicate that especially lipophilic alkoxy, benzyloxy, and phenoxy substituents with additional electron-demanding properties in the ...