A compound, or a pharmaceutically acceptable salt thereof, represented by the formula (1), (wherein, the carbon atom marked with an * is in the R-configuration, R 1 represents a hydrogen atom, a halogen atom, an amino group, a hydroxyl group, a hydroxyamino group, a nitro group, a cyano group, a sulfamoyl group, a C 1 -C 6 alkyl group, or a C 1 -C 6 alkoxy group, R 2 represents a C 3 -C 6 cycloalkylsulfanyl group, a C 3 -C 6 cycloalkylsulfinyl group, or a C 3 -C 6 cycloalkylsulfonyl group, and A represents a substituted or unsubstituted heteroaryl group).
