This invention relates to compounds of the formula (I) or a pharmaceutically acceptable salt thereof, wherein X is O or NH, and -A-B- is -0-CH2-, -CH2-O-, -S-CH2- or -CH2-S- or a pharmaceutically acceptable salt, and compositions containing such compounds and the use of such compounds in the treatment of a condition mediated by acid pump antagonistic activity such as, but not limited to, gastrointestinal disease, gastroesophageal disease, gastroesophageal reflux disease (GERD), peptic ulcer, gastric ulcer, duodenal ulcer, NSAID- induced ulcers, gastritis, infection of Helicobacter pylori, dyspepsia, functional dyspepsia, Zollinger-Ellison syndrome, non- erosive reflux disease (NERD), visceral pain, heartburn, nausea, esophagitis, dysphagia, hypersalivatiop, airway disorders or asthma.
