Synthesis and histamine H2 agonistic activity of arpromidine analogues: replacement of the pheniramine-like moiety by non-heterocyclic groups

Article abstract of DOI:10.1016/0223-5234(92)90145-Q

Analogues of the potent histamine H2 agonist arpromidine, characterized by non-hetrocyclic groups (phenyl, cyclohexyl, alkyl) instead of the pheniramine-like portion, were prepared and tested for their H2 agonistic and H1 antagonistic activity in the isolated guiea pig right atrium and ileum, respectively.In the diphenylpropylguanidine series an increase in H2 agonistic potency resulted from mono- or difluorination at one or both phenyl rings in the meta and/or para position (pD2 < 7.75 vs pD2 = 7.15 for the unsubstituted parent compound).Compounds chlorinated atboth phenyl rings were considerably less potent.Highest combined H2 agonistic/H1 antagonistic potency was found in the 4-fluorophenyl series.The arpromidine analogue with cyclohexyl and methyl group instead of phenyl and pyridine ring proved to be 30 times more potent than histamine in the atrium.The H1 antagonistic potency in cyclohexyl compounds was lower than in the diaryl series.Thus, aromatic rings appear not to be required for high H2 agonistic potency but are useful for combined H2 agonistic/H1 antagonistic activity. histamine / H2 receptor / H2 agonist / arpromidine / impromidine / H1 antagonist / antihistamine