| abstract |
The present invention provides a compound of the formula (I):n n(wherein, R 1 is ethyl optionally substituted by halogen or amino optionally substituted by lower alkyl, nR 2 and R 3 are each independently hydrogen or lower alkyl, nX is cycloalkylene, lower alkylene or piperidinediyl, nZ is optionally substituted phenyl or optionally substituted heterocyclyl) prodrug, pharmaceutically acceptable salt or solvate thereof.. |