A condensed heterocyclic compound and a salt thereof which have medical uses

摘要

The present invention relates to a novel condensed heterocyclic compound of formula (I) wherein R<1> is alkyl, etc.; R<2> is hydrogen, etc.; R<3> and R<4> are each independently hydrogen, etc.; a group of formula (a) is the group of formula (b), etc.; and a pharmaceutically acceptable salt thereof, which is useful as a medicament; the processes for the preparation of said condensed heterocyclic compound or a salt thereof; a pharmaceutical composition comprising said condensed heterocyclic compound or a pharmaceutically acceptable salt thereof; etc.