Abstract: The present invention provides a target protein degradation-inducing compound that is a bifunctional compound having a portion that binds to VHL, which is a substrate recognition protein of a ubiquitin ligase complex, at one end, and a portion that binds to a target protein at the other end. Specifically, a compound represented by the following structural formula (I): wherein each symbol is as defined in the present specification, or a pharmacologically acceptable salt thereof.

Abstract: The present invention provides: a novel use of a specific bicyclic nitrogen-containing heterocyclic compound as a PDE7 inhibitor; a novel bicyclic nitrogen-containing heterocyclic compound having a PDE7 inhibitory effect, a method for producing the compound, a use of the compound, and a pharmaceutical composition containing the PDE7 inhibitor or the compound; and others. More specifically, the present invention provides a PDE7 inhibitor containing the compound represented by the formula (I): [wherein the symbols have the same meanings as those described in the description] or a pharmaceutically acceptable salt thereof as an active ingredient.