A compound represented by the formula (I) below or a pharmaceutically acceptable salt thereof has an effect of inhibiting binding between S1P and its receptor Edg-1(S1P1), and is useful as a pharmaceutical product. [where A represents a sulfur atom, an oxygen atom, a formula —SO— or a formula —SO2—; R1 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or the like; R2 represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms or the like; R3 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R4 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group or the like; R5 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; and R6 represents an alkyl group having 1 to 6 carbon atoms, a phenyl group or a substituted phenyl group].