abstract |
The present invention belongs to the technical field of medicine, and specifically relates to the PDE9 inhibitor compounds represented by formula (II) or their pharmaceutically acceptable salts and stereoisomers. The present invention also relates to pharmaceutical preparations, pharmaceutical compositions and applications of these compounds. . X 2 , X 3 , X 4 , R 1 , R 2 , R 3 , rings A, L and m are as defined in the specification. The compounds of the present invention can be used to prepare medicines for treating or preventing related diseases mediated by PDE9. |