PYRIDONECARBOXYLIC ACID DERIVATIVE.

摘要

A compound represented by general formula (I), a pharmaceutically acceptable salt of ester thereof, a process for the production thereof, and an antitumor agent containing the same as the active ingredient. In formula (I), R<1> represents linear, branched or cyclic lower alkyl, or optionally fluorinated phenyl; R<2> and R<3> represent each hydrogen, or linear, branched or cyclic lower alkyl; R<4> represents hydrogen or N(R<5>)R<6>, wherein R<5> and R<6> represent each hydrogen, or linear, branched or cyclic lower alkyl; X represents nitrogen or C-Y, wherein Y represents hydrogen, halogen, methyl or methoxy; m and n represent each an integer of 0 or 1; and @ represents a single or double bond.