Structure-basicity and structure-affinity relationships of beta-adrenergic blocking agents.
pKa's of fourteen beta-receptor blockers, isoproterenol and norepinephrine, were determined potentiometrically. A Hammett analysis indicated that the influence of ring substituents on the basicity of the amines is attenuated by the ethanolic chain and abolished by the propranoloxy chain of beta-receptor blockers. The effect of ring substituents in phenoxypropranolamines upon affinity for the beta-adrengeric receptors is therefore unrelated to the strength of the bases. Two alterantive hypotheses are fowarded to explain why phenoxypropranolamines have greater affinities for the beta-receptors than phenethanolamines.
D000319:Adrenergic beta-Antagonists / Q000032:analysis*; D000345:Affinity Labels; D055598:Chemical Phenomena; D002621:Chemistry; D007545:Isoproterenol / Q000032:analysis; D008968:Molecular Conformation; D009638:Norepinephrine / Q000032:analysis; D013329:Structure-Activity Relationship
D000319:Adrenergic beta-Antagonists; D000345:Affinity Labels; D007545:Isoproterenol; D009638:Norepinephrine