Provided is a novel compound represented by formula [I] or a pharmaceutically acceptable salt thereof having antagonistic activity against group II metabolism-type glutamic acid (m-Glu) receptors. The compound or pharmaceutically acceptable salt thereof is useful as a prophylactic or therapeutic agent for diseases such as new mood disorders (depressive and bipolar disorders), anxiety disorders (generalized anxiety disorder, panic disorder, obsessive-compulsive disorder, social anxiety disorder, post-traumatic stress disorder, specific phobias, and acute stress disorder), schizophrenia, Alzheimer's disease, cognitive dysfunction, dementia, drug dependence, convulsions, tremors, pain, sleep disorders, and the like.
