It is an object of the present invention to provide a medicament for preventing or treating hyperphosphatemia. Solution: A compound represented by general formula (I) or a pharmacologically acceptable salt thereof. [In the formula, R1: a methyl group or the like, R2: a hydrogen atom or the like, R3: a hydrogen atom or the like, A: a cyclohexyl ring or the like, X: CH or the like, Y: CH or the like, Z: CH or the like, and n: 2 or the like.]
