Problem to be solved: to provide a novel dihydropyranopyrimidinone derivative, its tautomeric substance, its stereoisomer and mixture, or its pharmaceutically acceptable salt, and a pharmaceutical composition for prevention or treatment of thylakase related disease comprising it as an active ingredient.Solution - 2 - (4 - (2,6-difluoro-4 - (2-methoxyethoxy) phenyl) piperazine-1-yl) - 7,8-dihydro-3h-pyrano [4,3-d] pyrimidine-4 (5H) - - dihydropyranozozo having specific chemical structure represented by on Midione derivatives, their tautomers, their stereoisomers or their pharmaceutically acceptable salts.No selection【課題】新規なジヒドロピラノピリミジノン誘導体、その互変異性体、その立体異性体および混合物、又はその薬学的に許容可能な塩、及びそれを有効成分として含むタンキラーゼ関連疾患の予防又は治療用薬学的組成物の提供。【解決手段】２－（４－（２，６－ジフルオロ－４－（２－メトキシエトキシ）フェニル）ピペラジン－１－イル）－７，８－ジヒドロ－３Ｈ－ピラノ［４，３－ｄ］ピリミジン－４（５Ｈ）－オンに代表される、特定の化学構造を有するジヒドロピラノピリミジノン誘導体、その互変異性体、その立体異性体又はその薬学的に許容可能な塩。【選択図】なし
