Provided is a compound having a superior acid secretion suppressive action, antiulcer activity and the like. A compound represented by the formula (I) wherein R1 is a substituent； R2 (i) is a hydrogen atom,(ii) a C1-6 alkyl group optionnally having a halogen atom, or (iii) a cyano group； R3 is (i) a hydrogen atom, (ii) a halogen atom, a (iii) cyano group, (iv) a C1-6 alkyl group optionally having a halogen atom, or a C1-6 alkoxy group optionally having a halogen atom； one of R2 and R3 is a hydrogen atom and the other is a substituent other than a hydrogen f.
