Structural variations of 1-(4-(phenoxymethyl)benzyl)piperidines as nonimidazole histamine H3 receptor antagonists.
Recent bioisoteric replacements in histamine H3 receptor ligands with an exchange of the imidazole moiety by a piperidino group as well as of the trimethylene chain in 4-((3-phenoxy)propyl)-lH-imidazole derivatives (proxifan class) by an alpha,alpha'-xylendiyl linker represents the starting point in the development of 1-(4-(phenoxymethyl)benzyl)piperidines as a new class of nonimidazole histamine H3 receptor antagonists. According to different strategies in optimization of imidazole-containing antagonists the central benzyl phenyl ether moiety was replaced by numerous other polar functionalities. Additionally, the ortho- and meta-analogues of the lead were synthesized to determine the influence of the position of the piperidinomethyl substituent. The new compounds were tested in an in vitro binding assay for their affinities for cloned human H3 receptors stably expressed in CHO-K1 cells and for their oral in vivo potencies brain in a functional screening assay in the brain of mice. Additionally, activities of selected compounds were determined in the guinea-pig ileum functional test model. In contrast to the analogues ortho-substituted compounds all other compounds maintained respectable affinities for the human H3 receptor (-log Ki values 6.3-7.5). Despite the results from other classes of compounds the 4-methyl substituted derivatives generally displayed higher affinities than the corresponding 4-chloro substituted compounds. In vivo only the inverse phenyl benzyl ether (3) showed worthwhile antagonist potencies.
Mikó
Tibor
T
Institut für Pharmazie, Freie Universität Berlin, Königin-Luise-Strasse 2+4, 14195 Berlin, Germany.
Ligneau
Xavier
X
Pertz
Heinz H
HH
Arrang
Jean-Michel
JM
Ganellin
C Robin
CR
Schwartz
Jean-Charles
JC
Schunack
Walter
W
Stark
Holger
H
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D006168:Guinea Pigs; D006633:Histamine Antagonists / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D015394:Molecular Structure; D010880:Piperidines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D018100:Receptors, Histamine H3 / Q000378:metabolism
D006633:Histamine Antagonists; D007093:Imidazoles; D010880:Piperidines; D018100:Receptors, Histamine H3