[3-(1H-Imidazol-4-yl)propyl)guanidines Containing Furoxan Moieties: A New Class of H3-Antagonists Endowed with NO-Donor Properties

Synthesis and pharmacological characterisation of a series of products obtained by coupling the H3-antagonist SKF 91486 through appropriate spacers with the NO-donor 3-phenylfuroxan-4-yloxy and 3-benzenesulfonylfuroxan-4-yloxy moieties, as well as with the corresponding furazan substructures, devoid of NO-donating properties, are reported. All the products were tested for their H3-antagonistic and H2-agonistic properties on electrically-stimulated guinea-pig ileum segments and guinea-pig papillary muscle, respectively. The whole series of compounds displayed good H3-antagonist behaviour and feeble partial H2-agonist activity. Among furoxan derivatives, the benzenesulfonyl hybrid 28, a good NO-donor, triggered a dual NO-dependent muscle relaxation and H3-antagonistic effect on guinea-pig intestine.