The present invention provides a pyrazolo [1,5-a] pyrimidine compound, having CB1 receptor-antagonizing activity, of the following formula [I]:in which R1and R2are the same or different and each an optionally substituted aryl group etc, R0is hydrogen atom, an alkyl group etc, E is a group of the formula: -C(=O)- or -SO2-, R is a group of the following formula [i], [ii] or [iii] etc:Ring A is (a) a C3-8cycloalkyl group optionally fused to a benzene ring or (b) a benzene ring, Q is a single bond or a methylene group, Ring B is a 4- to 7-membered aliphatic heterocyclic group, said cyclic group binding via its ring-carbon atom to the adjacent nitrogen atom, X is sulfur atom etc, R3is an alkyl group optionally substituted by an alkylthio group, R4is hydrogen atom, an alkyl group etc, one of RAand RBis an alkyl group etc, and the other is hydrogen atom, an alkyl group etc, or a pharmaceutically acceptable salt thereof.本發明提供一種具有CB1受體拮抗活性之下式[I]吡唑并[1,5-a]嘧啶化合物:其中R1及R2為相同或相異且各自為視需要經取代之芳基等,R0為氫原子、烷基等,E為下式基團:-C(=O)-或-SO2-,R為下式[i]、[ii]或[iii]之基團等:環A為(a)視需要稠合至苯環之C3-8環烷基或(b)苯環,Q為單鍵或亞甲基,環B為4員至7員脂肪族雜環基,該環系基團係透過其環碳原子鍵結至相鄰氮原子,X為硫原子等,R3為視需要經烷硫基取代之烷基,R4為氫原子、烷基等,RA及RB中之一者為烷基等,另一者為氫原子、烷基等或其醫藥上可接受之鹽。
