Histamine analogues: imidazolylalkylguanidines, synthesis and in vitro pharmacology
摘要:
Impromidine analogues characterized by modified side chains connecting the guanidine and imidazole moieties have been prepared and tested for H-2-agonistic activity on isolated guinea-pig right atrium and for H-1-antagonistic activity on guinea-pig ileum, respectively. 3-(1H-Imidazol-4-yl)propylguanidines with varied cimetidine-like side chain (5a-d) proved to be almost full H-2-agonists and 5-70 times more potent than histamine, whereas compounds with beta- or gamma-methyl branched imidazolylpropyl moiety (5e, 5f, 5h) are only weak partial H-2-agonists. Both unsaturated impromidine analogues (5i, 5j) are full H-2-agonists, the (Z)-configurated compound 5j being about 4 times more potent than the (E)-configurated derivate 5i.
In the search for potential bioisosteres of the 4-imidazolyl ring in acylguanidines (e.g. UR-AK24), known to possess affinity to several histamine receptor subtypes (HxR, x = 1–4), and cyanoguanidine-type H4R agonists (e.g. UR-PI376), the contribution of various heterocycles to agonism, antagonism and HR subtype selectivity was studied (recombinant human H1,2,3,4Rs, isolated guinea pig organs (H1R, H2R)). While minor structural modifications of UR-PI376 analogues were not tolerated regarding H4R agonism, in the case of the acylguanidines, a 1,2,4-triazole ring shifted the selectivity toward the H2R.
Imidazole derivatives which are useful intermediates for the production of compounds having pharmacological activity at histamine H.sub.2 receptors. A specific compound of the present invention is 4-(4-aminobutyl)-1,3-dihydro-5-methyl-2H-imidazole-2-thione, hereinafter referred to as 4-(4-Aminobutyl)-5-methylimidazole-2-thione.
Isocytosine H2-receptor histamine antagonists II. Synthesis and evaluation of biological activity at histamine H1- and H2-receptors of 5-(heterocyclyl)methylisocytosines
2-nitro aminopyrimidone derivatives, a process for their preparation and their use to prepare 2-aminopyrimidone derivatives which have histamine H2-antagonist activity
申请人:SMITH KLINE & FRENCH LABORATORIES
LIMITED
公开号:EP0004793B1
公开(公告)日:1981-12-30
Pyridylalkylpyrimidone compounds, process for preparing them and pharmaceutical compositions containing them