PROBLEM TO BE SOLVED: To provide a new compound or a pharmaceutically acceptable salt useful for treatment or prevention of sleep disorder, depression, anxiety disorder, panic disorder, schizophrenia, drug dependence, Alzheimer disease, Parkinson disease, Huntington chorea, eating disorder, headache, migraine, pain, digestive system disease, epilepsy, inflammation, immunology-related disease, endocrine related disease, hypertension or the like, based on an orexin (OX) receptor antagonism effect.SOLUTION: There is provided a compound represented by the formula (I) or a pharmaceutically acceptable salt thereof. Ris H, halogen, a Calkyl group or the like, Ris a triazolyl group, a pyridyl group, or a pyrimidinyl group, Rand Rare each independently H, halogen, a Calkyl group or the like, Xand Xare each independently N or CH, Y is pyrazole, triazole, tetrazole or oxadiazole.SELECTED DRAWING: None【課題】オレキシン（ＯＸ）受容体拮抗作用に基づいた、睡眠障害、うつ病、不安障害、パニック障害、統合失調症、薬物依存症、アルツハイマー病、パーキンソン病、ハンチントン舞踏病、摂食障害、頭痛、片頭痛、疼痛、消化器疾患、てんかん、炎症、免疫関連疾患、内分泌関連疾患、高血圧等の疾患の治療又は予防に有用な新規化合物又はその医薬上許容される塩の提供。【解決手段】式（Ｉ）で示される化合物又はその医薬上許容される塩。［Ｒ１はＨ、ハロゲン、Ｃ１－６アルキル基等；Ｒ２は卜リアゾリル基、ピリジル基又はピリミジニル基；Ｒ３及びＲ４は各々独立にＨ、ハロゲン、Ｃ１－６アルキル基等；Ｘ１及びＸ２は各々独立にＮ又はＣＨ；Ｙはピラゾール、トリアゾール、テトラゾール又はオキサジアゾール］【選択図】なし
