| abstract |
Disclosed is a substance having an antagonistic effect on the binding of histamine to a histamine H3 receptor or an inhibitory effect on the activity which a histamine H3 receptor constantly exhibits. A compound represented by the formula (I) or a pharmaceutically acceptable salt thereof; (I) n n n n n n n n n n wherein R1 represents a phenyl group which may be substituted or the like and R2 represents a cyano group which may be substituted or the like, or R1 and R2 together form an aliphatic heterocylic ring which may be substituted; R3 represents a group represented by the formula (II-1) below; n n n n n n n n n n and all of X1 to X4 represent a carbon atom or the like: (II-1) where R4 and R5 represent a lower alkyl group or the like; and m1 represents an integer of 2 to 4. |