Compounds capable of inhibiting replication of the hepatitis C virus (“HCV”) are described. This invention also relates to processes of making such compounds, compositions comprising such compounds, and methods of using such compounds to treat HCV infection.
[Problem]
To provide a compound useful as medicine having PDE4B inhibitory activity, in particular, as an active ingredient of a composition for treating or preventing schizophrenia, Alzheimer's disease, dementia, depression and the like.
[Measures for Solution]
The present inventors examined compounds having PDE4B inhibitory activity and found that a tricyclic or tetracyclic imidazo[1,2-a]pyridine derivative or salts thereof had a superior PDE4B inhibitory activity, thereby completing the present invention. The imidazo[1,2-a]pyridine derivative can be used as an agent for treating or preventing schizophrenia, Alzheimer's disease, dementia, depression and the like.