| abstract |
There is provided a novel bicyclic or tricyclic heterocyclic compound represented by the following formula (I): or a pharmaceutically acceptable salt thereof: Wherein ring A is an optionally substituted aromatic group, One of X 1 and X 2 is a carbon atom and the other is a nitrogen atom, X 3 is a nitrogen atom, or CR 2 , X 4 is a nitrogen atom, or CR 3 , X 5 is a sulfur atom, or -CH = CH-, Z 1 is an oxygen atom, -C (R 6 ) (R 7 ) -, -NH-, -C (R 6 ) (R 7 ) -NH-, -NH-C (R 6 ) (R 7 ) -C (R 6) (R 7 ) -O-, -OC (R 6) (R 7) -, or a single bond, Z 2 and One of Z 3 is CH and the other is a nitrogen atom, or both are a nitrogen atom, Other symbols are as defined in the Detailed Description]. |