A compound represented by the formula (I): [wherein X1 represents oxygen, etc.; X2 represents nitrogen, etc.; X3 represents nitrogen, etc.; X4 represents nitrogen, etc.; and R<1> represents the formula (II-1): (A) ring A (wherein X5 represents sulfur, etc.; A1 represents carbon, etc.; A2 represents nitrogen, etc.; and ring A represents phenyl, etc.)] or a pharmaceutically acceptable salt of the compound. They have mGluR1 inhibitory activity and are useful in the prevention or treatment of convulsion, acute pains, inflammatory pains, chronic pains, brain disorders such as brain infarction or transient cerebral ischemic attack, mental function disorders such as schizophrenia, anxiety, drug dependence, Parkinson's disease, or gastrointestinal disorders. |