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Structure-basicity and structure-affinity relationships of beta-adrenergic blocking agents.
Acta Physiologica Latino Americana
|January 1, 1975
Summary
The basicity of beta-receptor blockers is influenced by their structure, with the propranoloxy chain significantly reducing substituent effects. This finding suggests receptor affinity is independent of base strength in these drugs.
Area of Science:
- Pharmacology
- Medicinal Chemistry
Background:
- Beta-receptor blockers are crucial drugs for treating cardiovascular conditions.
- Understanding the structure-activity relationship of these blockers is essential for drug design.
Purpose of the Study:
- To determine the pKa values of fourteen beta-receptor blockers and related compounds.
- To investigate the influence of structural modifications on the basicity of beta-receptor blockers.
- To explore the relationship between basicity and affinity for beta-adrenergic receptors.
Main Methods:
- Potentiometric determination of pKa values.
- Hammett analysis to assess the impact of ring substituents on amine basicity.
Main Results:
- The ethanolic chain in beta-receptor blockers attenuates the effect of ring substituents on amine basicity.
- The propranoloxy chain abolishes the influence of ring substituents on basicity.
- The affinity of phenoxypropranolamines for beta-adrenergic receptors is not correlated with their basicity.
Conclusions:
- Structural features, not basicity, dictate the affinity of phenoxypropranolamines for beta-receptors.
- Two novel hypotheses are proposed to explain the higher affinity of phenoxypropranolamines compared to phenethanolamines.