The present invention provides the compound with PDE inhibitory effect, it is suitable for the drug as prevention or treatment schizophrenia etc.. The compound or its salt of formula (I0): wherein R1 indicates substituent group; R2 indicates hydrogen atom or substituent group; R3 indicates hydrogen atom or substituent group; Ring A expression can substituted aromatic rings; Indicating with ring B can the miscellaneous aromatic rings of substituted 5- member.本發明提供了具有PDE抑制效果的化合物,其適用於作爲預防或治療精神分裂症等的藥物。式(I0)的化合物,或其鹽:其中R1表示取代基;R2表示氫原子或取代基;R3表示氫原子或取代基;環A表示可被取代的芳香環;和環B表示可被取代的5-元雜芳香環。