PROBLEM TO BE SOLVED: To provide a novel compound having a P2X7 receptor inhibitory action, and a pharmaceutical composition having a P2X7 receptor inhibitory action.SOLUTION: The present invention provides a compound represented by formula (I) (where R5b is a substituted or unsubstituted alkyl or the like; R1 is a substituted or unsubstituted aromatic carbocyclic group or the like; =A- is =CR10aa- or the like; R9a is a substituted or unsubstituted alkyl or the like; R10aa and R10ad independently represent a hydrogen atom or the like; R10ab is a hydrogen atom or the like; R10ac is a substituted or unsubstituted aromatic heterocyclic group), or a pharmaceutically acceptable salt thereof.SELECTED DRAWING: NoneCOPYRIGHT: (C)2020,JPO&INPIT【課題】 P2X7受容体阻害作用を有する新規化合物およびP2X7受容体阻害作用を有する医薬組成物を提供する。【解決手段】 式(I):【化1】(式中、R5bは、置換若しくは非置換のアルキル等;R1は、置換若しくは非置換の芳香族炭素環式基等;=A-は、=CR10aa-等;R9aは、置換若しくは非置換のアルキル等;R10aaおよびR10adは、それぞれ独立して、水素原子等;R10abは、水素原子等;R10acは、置換若しくは非置換の芳香族複素環式基)で示される化合物、またはその製薬上許容される塩。【選択図】なし