136604-66-5Relevant articles and documents
Synthesis and structure-activity relationships of cyanoguanidine-type and structurally related histamine H4 receptor agonists
Igel, Patrick,Geyer, Roland,Strasser, Andrea,Dove, Stefan,Seifert, Roland,Buschauer, Armin
supporting information; experimental part, p. 6297 - 6313 (2010/03/24)
Recently, we identified high-affinity human histamine H3 (hH3R) and H4 receptor (hH4R) ligands among a series of NG-acylated imidazolylpropylguanidines, which were originally designed as histamine H2 receptor (H2R) agonists. Aiming at selectivity for hH4R, the acylguanidine group was replaced with related moieties. Within a series of cyanoguanidines, 2-cyano-1-[4-(1H-imidazol-4-yl)butyl]-3-[(2-phenylthio)ethyl]guanidine (UR-PI376, 67) was identified as the most potent hH4R agonist (pEC50=7.47, α=0.93) showing negligible hH1R and hH2R activities and significant selectivity over the hH3R (pKB=6.00, α=-0.28), as determined in steady-state GTPase assays using membrane preparations of hHxR-expressing Sf9 cells. In contrast to previously described selective H4R agonists, this compound and other 3-substituted derivatives are devoid of agonistic activity at the other HR subtypes. Modeling of the binding mode of 67 suggests that the cyanoguanidine moiety forms chargeassisted hydrogen bonds not only with the conserved Asp-94 but also with the hH4R-specific Arg-341 residue. 2-Carbamoyl-1-[2-(1H-imidazol-4-yl)ethyl]-3-(3-phenylpropyl)guanidine (UR-PI97, 88) was unexpectedly identified as a highly potent and selective hH3R inverse agonist (pKB=8.42, >300-fold selectivity over the other HR subtypes). 2009 American Chemical Society.
