First metal-containing histamine H3 receptor ligands.

Iron-containing ligands targeting the human histamine H(3) receptor (hH(3)R) were prepared. The compounds contain ferrocene sandwich complexes coupled via different linkers to a basic hH(3)R antagonist/inverse agonist pharmacophore. In a click chemistry approach, a triazole was successfully inserted as a new linking element. Two ferrocenylmethylamines and a ferrocenyltriazole were the most affine hH(3)R ligands within this series, showing receptor binding in the nano- and subnanomolar concentration range.