An object of the present invention is to provide compounds which have antitumor activity and do not change cytomorphosis. Disclosed are compounds represented by formula (I) and a pharmaceutically acceptable salts and solvates thereof and pharmaceutical compositions comprising said compounds: <；CHEM>； wherein X and Z each independently represent CH or N； R<；1>； to R<；3>； represent H, substituted alkoxy, unsubstituted alkoxy or the like； R<；4>； represents H； R<；5>； to R<；8>； represent H, halogen, alkyl, alkoxy, alkylthio, nitro, or amino, provided that R<；5>； to R<；8>； do not simultaneously represent H； R<；9>； and R<；10>； represent H, alkyl, or alkylcarbonyl； and R<；11>； represents alkyl, alkenyl, alkynyl, or aralkyl.
