title: The histamine H2 receptor agonist impromidine: synthesis and structure-activity considerations.
abstract: Impromidine (1) is a potent and selective histamine H2 receptor agonist and its structure comprises a strongly basic guanidine group containing two different imidazole-containing side chains. In this paper we report the synthesis of analogues in which both of the side chains and the guanidine group are modified and tested as agonists or antagonists at histamine H2 receptors on guinea pig atrium. A protonated amidine group linked by a chain of three carbon atoms to a tautomeric imidazole ring appears to be an essential feature for agonist activity and it is suggested that the second imidazole-containing side chain in impromidine mainly contributes toward affinity for histamine H2 receptors.
authors.forename: G J
authors.initials: GJ
authors.lastname: Durant
authors.forename: C R
authors.initials: CR
authors.lastname: Ganellin
authors.forename: D W
authors.initials: DW
authors.lastname: Hills
authors.forename: P D
authors.initials: PD
authors.lastname: Miles
authors.forename: M E
authors.initials: ME
authors.lastname: Parsons
authors.forename: E S
authors.initials: ES
authors.lastname: Pepper
authors.forename: G R
authors.initials: GR
authors.lastname: White
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002627:Chemistry, Physical; D006224:Cricetinae; D006632:Histamine / Q000494:pharmacology; D007093:Imidazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D017446:Impromidine; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D011968:Receptors, Histamine / Q000187:drug effects*; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D007093:Imidazoles; D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D006632:Histamine; D017446:Impromidine