(EN) A process for preparing a compound represented by formula (Y1) or (Y2) [wherein Rx is an optionally substituted carbocyclyl -lower-alkyl group, or the like], using a novel process for preparing a pyridone derivative represented by formula (X4) [wherein R1d is hydrogen, halogen, or the like; R2d is hydrogen, a lower alkyl group, or the like, said lower alkyl group being optionally substituted with one or more selected from substituent group E; R4d is a lower alkyl group or the like, said lower alkyl group being optionally substituted with one or more selected from substituent group E; and R6d is a lower alkyl group or the like, said lower alkyl group being optionally substituted with one or more selected from substituent group E].
(ZH) 式（Y1）或式（Y2）（式中，RX为可被取代的碳环低级烷基等）所示的化合物或其盐的制造方法，其使用了式（X4）（式中，R1d为氢、卤素等，R2d为氢、可被取代基组E取代的低级烷基等，R4d为可被取代基组E取代的低级烷基等，以及R6d为可被取代基组E取代的低级烷基等）所示的吡啶酮衍生物的新的制造方法，。