Related Experiment Video
Updated: Aug 29, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
2-(4'-aminobenzenamine)-pyrimidine, a new alpha-antagonist from Autonoë madeirensis
Catarina Dias1, Alexandra Paulo, José Nascimento
1CECF, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
Abstract:
A new natural pyrimidine derivative, 2-(4'-aminobenzenamine)-pyrimidine (1), was isolated from the bulbs of Autonoë madeirensis, a Hyacinthaceae of the Madeira Archipelago (Portugal) and the structure determined on the basis of spectroscopic data. As some pyrimidine compounds are important alpha1-adrenergic antagonists, we investigated the effect of 1 on rat vas deferens contractility induced by the alpha1-agonist phenylephrine. In concentrations virtually devoid of effect on the rat vas deferens contractility, 1 shifted to the right the concentration-response curves of phenylephrine without changing the maximal effect. These results provide evidence that 1 acts as an alpha1-adrenoceptor antagonist and suggest a competitive mechanism of action.
Related Concept Videos
Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
Physical Properties of Amines
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
Parkinson's Disease: Treatment
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
Drugs Affecting Neurotransmitter Release or Uptake
