A novel triazine derivative is provided. A triazine derivative represented by the formula (I) or a pharmaceutically acceptable salt thereof. (Wherein R1 represents an aryl group which may have a substituent, a heterocyclic ring which may have a substituent, a heterocyclic condensed ring which may have a substituent, or a substituent； Represents an alkynyl group which may have, R2 represents a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, an alkoxy group which may have a substituent, and R3 represents a substituent. An aryl group that may have, a heterocyclic ring that may have a substituent, a heterocyclic condensed ring that may have a substituent, R4 is a hydrogen atom, a lower group that may have a substituent Represents an alkyl group, an alkoxy group which may have a substituent, an amino group which may have a substituent, or a halogen atom, and R5 represents a hydrogen atom or a lower alkyl group which may have a substituent. Or a saturated or unsaturated 5- or 6-membered ring which may form a bond with R1 and may have a substituent By forming, they may form a polycyclic condensed ring.) .BACKGROUND【課題】新規なトリアジン誘導体の提供。【解決手段】式（Ｉ）で示されるトリアジン誘導体またはその薬学的に許容される塩。【化１】（式中、Ｒ１は、置換基を有してもよいアリール基、置換基を有してもよい複素環、置換基を有してもよい複素環式縮合環、置換基を有してもよいアルキニル基を表し、Ｒ２は、水素原子、ハロゲン原子、置換基を有してもよい低級アルキル基、置換基を有してもよいアルコキシ基を表し、Ｒ３は、置換基を有してもよいアリール基、置換基を有してもよい複素環、置換基を有してもよい複素環式縮合環を表し、Ｒ４は、水素原子、置換基を有してもよい低級アルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアミノ基、ハロゲン原子を表し、Ｒ５は、水素原子、置換基を有してもよい低級アルキル基を表すか、あるいはＲ１と結合を形成し、置換基を有することもある飽和もしくは不飽和の、５ないし６員環を形成することによって、多環性縮合環を形成してもよい。）【選択図】なし
