The 5-HT7 receptor is the most recent addition to the 5-HT receptor family and has been linked to a variety of physiological and pathophysiological processes. Well established antide-pressant pharmaceuticals have recently been found to activate the 5-HT7 receptor, supporting the role of the 5-HT7 receptor in the antidepressant mechanism. The synthesis of potent selec-tive 5-HT7 receptor antagonists could afford a greater understanding of the 5-HT7 receptor function as well as lead to potential drug candidates.

The synthesis of unfused biheteroaryl derivatives as 5-HT7 receptor ligands has been de-scribed within. These compounds have been tested for biological activity on the 5-HT6 and 5-HT7 receptors. 4-(3’-Furyl)-2-(N-substituted-piperazino)pyrimidines were found to be potent 5-HT7 receptor ligands. 4-(2’-Furyl)-2-(N-substituted-piperazino)pyrimidines have shown high se-lectivity for the 5-HT7 receptor over the 5-HT6 receptor.