A process for preparing a compound represented by formula (Y1) or (Y2) [wherein Rx is an optionally substituted carbocyclyl lower alkyl, or the like] or a salt thereof, 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 optionally substituted with substituent E, or the like; R4d is a lower alkyl optionally substituted with substituent E, or the like; and R6d is a lower alkyl group optionally substituted with substituent group E].
[Chemical formula 8]
一种制备式(Y1)或(Y2)代表的化合物[其中Rx为任选取代的羰基低级烷基或类似物]或其盐的工艺,该工艺采用了制备式(X4)代表的
吡啶酮衍
生物的新工艺[其中R1d为氢、卤素或类似物;R2d为氢、任选被取代基E取代的低级烷基或类似物;R4d为任选被取代基E取代的低级烷基或类似物;R6d为任选被取代基E取代的低级烷基]。
[
化学式 8]