| abstract |
The object is to provide a compound having an excellent inhibitory effect on acid secretion and showing an anti-ulcer activity or the like. Disclosed is a proton pump inhibitor comprising a compound represented by the formula (I) or a salt thereof or a prodrug of the compoun or the salt: (I) wherein the ring A represents a saturated or unsaturated 5- or 6-membered ring group which, in addition to a carbon atom, may have 1 to 4 heteroatoms each selected a nitrogen atom, an oxygen atom and a sulfur atom as the ring-constituting atoms; the ring-constituting atoms X1 and X2 independently represent a carbon atom or a nitrogen atom; the ring-constituting atom X3 represents a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom; R1 represents an aryl group which may be substituted or a heteroaryl group which may be substituted; R2 represents an alkyl group which may be substituted, an aryl group which may be substituted or a heteroaryl group which may be substituted; and R3 is a substituent on a ring-constituting atom other than X1, X2 and X3 and represents an aminomethyl group which may be substituted by 1 to 2 lower alkyl groups, provided that the ring A may further has a substituent selected from a lower alkyl group, a halogen atom, a cyano group and an oxo group. |