The present invention provides a novel diazepine compound that blocks the IKurcurrent or the Kv1.5 channel potently and more selectively than other K+channels. The present invention relates to a diazepine compound represented by General Formula (1)or a salt thereof, wherein R1, R2, R3, and R4are each independently hydrogen, lower alkyl, cyclo lower alkyl or lower alkoxy lower alkyl； R2and R3may be linked to form lower alkylene； A1is lower alkylene optionally substituted with one or more substituents selected from the group consisting of hydroxyl and oxo； Y1and Y2are each independently -N= or -CH=； and R5is group represented bywherein R6and R7are each independently hydrogen or organic group； R6and R7may be linked to form a ring together with the neighboring group -XA-N-XB-； XAand XBare each independently a bond, lower alkylene, etc.本發明提供一種新穎的二氮呯化合物，其可有力阻斷IKur電流或Kv1.5通道且較其它K+通道更具選擇性。本發明係關於一種以通式(1)所表示的二氮呯化合物或其鹽類，其中R1、R2、R3及R4係各自獨立地為氫、低碳烷基、環低碳烷基或低碳烷氧低碳烷基；R2及R3可連接以形成低碳伸烷基；A1係低碳伸烷基，其任擇地以一或多個選自於由羥基及側氧基所組成群組中之取代基所取代；Y1及Y2係各自獨立地為-N=或-CH=；以及R5為由所表示之基團其中R6及R7係各自獨立地為氫或有機基團；R6及R7可與鄰接基團-XA-N-XB-連接以形成一環；XA及XB係各自獨立地為一鍵結、低碳伸烷基等。
