Synthesis and evaluation of homo-bivalent GnRHR ligands.

G protein coupled receptors (GPCRs) are important drug targets in pharmaceutical research. Traditionally, most research efforts have been devoted towards the design of small molecule agonists and antagonists. An interesting, yet poorly investigated class of GPCR modulators comprise the bivalent ligands, in which two receptor pharmacophores are incorporated. Here, we set out to develop a general strategy for the synthesis of bivalent compounds that are projected to bind to the human gonadotropin-releasing hormone receptor (GnRHR). Our results on the dimerisation of a known GnRHR antagonist, with as key step the Huisgen 1,3-cycloaddition, and their ability to bind to and antagonize GnRH-induced GnRHR stimulation, are presented here.