Provided is a compound having a superior acid secretion suppressive action, antiulcer activity and the like. A compound represented by the formula wherein R 1 is a substituent, R 2 is a hydrogen atom, a C 1-6 alkyl group optionally having a halogen atom or a cyano group, R 3 is a hydrogen atom, a halogen atom, a cyano group, a C 1-6 alkyl group optionally having a halogen atom or a C 1-6 alkoxy group optionally having a halogen atom, one of R 2 and R 3 is a hydrogen atom, and the other is a substituent other than a hydrogen atom, or a salt thereof.
