PROBLEM TO BE SOLVED: To provide a method of treating vitiligo.SOLUTION: The invention provides the compounds I and II shown in the figure, as well as prodrugs, hydrates, solvates, N-oxides, salts and pharmaceutical compositions containing them. The invention also provides a method of treating vitiligo using the compositions.SELECTED DRAWING: Figure 1【課題】白斑を治療する方法の提供。【解決手段】下記化合物IとII、およびプロドラッグ、水和物、溶媒和物、N-オキシド、塩、ならびに、それらを含有する薬学的組成物。前記組成物を用いた白斑の治療方法。【選択図】図1