Synthesis and renal vasodilator activity of some dopamine agonist 1-aryl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diols: halogen and methyl analogues of fenoldopam.
Certain 6-halo-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines were found to be potent D-1 dopamine agonists. The 1-(4-hydroxyphenyl) analogues did not have central nervous system activity because their high polarity inhibited entry into the brain. However, these compounds were potent renal vasodilators. Fenoldopam, the 6-chloro analogue, is an especially significant member of the series, and its synthesis, pharmacology, and clinical properties have been studied extensively. The 6-methyl and 6-iodo congeners were potent renal vasodilators, but nonpotent partial D-1 agonists as measured by stimulation of rat caudate adenylate cyclase. A possible rationalization suggests different receptor reserves for these activities. The 9-substituted benzazepines were either inactive or of low potency as dopamine agonists, while the N-methyl analogues had significant antagonist potency as measured by inhibition of dopamine stimulation of rat caudate adenylate cyclase.
D000262:Adenylyl Cyclases / Q000032:analysis; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects; D004285:Dogs; D018818:Fenoldopam; D011954:Receptors, Dopamine / Q000187:drug effects*; D012079:Renal Circulation / Q000187:drug effects*; D013329:Structure-Activity Relationship; D014665:Vasodilator Agents / Q000138:chemical synthesis* / Q000494:pharmacology
D001552:Benzazepines; D011954:Receptors, Dopamine; D014665:Vasodilator Agents; D000262:Adenylyl Cyclases; D018818:Fenoldopam