Nitric oxide (NO) donor beta(2)-agonists:furoxan derivatives containing the fenoterol moiety and related furazans

The structure of fenoterol, a â2-adrenoceptor agonist used in therapy, has been joined with furoxan NOdonor moieties to give new NO-donor â2-agonists. The furazan analogues, devoid of the property to release NO, were also synthesized for comparison. All the compounds retained â2-agonistic activity at micromolar or submicromolar concentration when tested on guinea pig tracheal rings precontracted with carbachol. Among the furoxan derivatives, the NO contribution to trachea relaxation was evident with product 15b at micromolar concentrations. All the new NO-donor hybrids were able to dilate rat aortic strips precontracted with phenylephrine. Both furoxan and furazan derivatives displayed antioxidant activity greater than that of fenoterol.