Diamine derivatives containing imidazolidinylidene propanedinitrile as a new class of histamine H3 receptor antagonists. Part I

Novel diamine derivatives containing imidazolidinylidene propanedinitrile were synthesized and evaluated for histamine H3 receptor-binding affinities. High-affinity ligands 3d, 3k, and 3n showed potent H3 receptor antagonism and excellent selectivity over human H1, H2 and H4 receptors.