THE PRESENT INVENTION IS DIRECTED TO PROVIDING A NOVEL COMPOUND USEFUL AS A THERAPEUTIC AGENT OR PROPHYLACTIC AGENT FOR ACID-RELATED DISEASES, WHICH HIGHLY INHIBITS GASTRIC ACID SECRETION, MORE PERSISTENTLY INHIBITS GASTRIC ACID SECRETION, AND IS APPROPRIATELY PHYSICOCHEMICALLY STABLE. SOLUTION A COMPOUND REPRESENTED BY THE FORMULA (1): [FORMULA 1) WHERE R1 AND R3 IS THE SAME OR DIFFERENT AND EACH REPRESENT A HYDROGEN ATOM OR A C1-C6 ALKYL GROUP, R2 REPRESENTS A (5,5-DIMETHYL-1,3-DIOXAN-2-YL) METHOXY GROUP OR THE LIKE R4, R5, R6 AND R7 EACH REPRESENT A HYDROGEN ATOM, HALOGEN ATOM, C1-C6 ALKYL GROUP, C1-C6 HALOALKYL GROUP, C1-C6 ALKOXY GROUP OR C1-C6 HALOALKOXY GROUP, AND W1 REPRESENTS A SINGLE BOND, METHYLENE GROUP OR ETHYLENE GROUP, OR A SALT THEREOF, OR A SOLVATE OF THESE.
