Tricyclic-fused heterocyclic PDE3 / 4 dual inhibitors, their preparation and use

Abstract

A tricyclic fused heterocyclic PDE3 / 4 dual inhibitor, a method for preparing said inhibitor, and its use are disclosed. Specifically, a compound of Formula I, or a pharmaceutically acceptable form thereof, is provided, wherein each substituent is as defined in the specification. The compound or pharmaceutically acceptable form thereof can be used as a phosphodiesterase inhibitor, and exhibits high activity.