| abstract |
Compounds represented by general formula (I); prodrugs of the same; or pharmaceutically acceptable salts of both; or solvates of them. In said formula, R?1, R2, R3 and R4¿ are each independently hydrogen, alkyl or the like; R?5 and R6¿ are each independently hydrogen, alkyl or the like; X is -O-, -S- or the like; Y is a divalent group derived from a five-membered aromatic heterocycle, or the like; and Z is optionally substituted aryl or the like. |