An object of the present invention is to provide compounds having potent antitumor activity. The compounds according to the present invention are compounds represented by formula (I) or pharmaceutically acceptable salts or solvates thereof: <;CHEM>; wherein X and Z represent CH or N; Y represents O or S; R<;1>;, R<;2>;, and R<;3>; represent H, alkoxy or the like; R<;4>; represents H; R<;5>;, R<;6>;, R<;7>;, and R<;8>; represent H, halogen, alkoxy or the like; R<;9>; and R<;10>; represent H, alkyl or the like; and R<;11>; represents optionally substituted azolyl.