Synthesis of 1,8-naphthyridine derivatives: potential antihypertensive agents - Part VIII

A series of (ethoxycarbonylpiperazinyl)- and piperazinyl-1,8-naphthyridine derivatives, variously substituted, has been synthesized and pharmacologically investigated for anthihypertensive activity. Some of them exhibited a significant and prolonged decrease of the mean arterial pressure (MAP) on spontaneously hypertensive rats. On the basis of the pharmacological results, no structure-activity relationship can be deduced at this time. Moreover, the most active compound 4e, was investigated by means of in vitro pharmacological functional studies and in vivo, as a diuretic agent, to determine a possible mechanism of the antihypertensive activity, which results in a probably non-competitive antagonism against alpha(1), vascular adrenoceptors. This mechanism was also shown by the compounds 8 and 13. (C) Elsevier, Paris.