Related Experiment Video
Updated: May 16, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
Pyrazolo[1,5-c]quinazoline derivatives and their simplified analogues as adenosine receptor antagonists: synthesis,
Daniela Catarzi1, Vittoria Colotta, Flavia Varano
1Dipartimento di Scienze Farmaceutiche, Laboratorio di Progettazione, Sintesi e Studio di Eterocicli Biologicamente Attivi, Universita' di Firenze, Polo Scientifico, Via Ugo Schiff 6, 50019 Sesto Fiorentino, FI, Italy. daniela.catarzi@unifi.it
Abstract:
A number of 5-oxo-pyrazolo[1,5-c]quinazolines (series B-1), bearing at position-2 the claimed (hetero)aryl moiety (compounds 1-8) but also a carboxylate group (9-14), were designed as hA(3) AR antagonists. This study produced some interesting compounds endowed with good hA(3) receptor affinity and high selectivity, being totally inactive at all the other AR subtypes. In contrast, the corresponding 5-ammino derivatives (series B-2) do not bind or bind with very low affinity at the hA(3) AR, the only exception being the 5-N-benzoyl compound 19 that shows a hA(3)K(i) value in the high μ-molar range. Evaluation of the synthetic intermediates led to the identification of some 5(3)-(2-aminophenyl)-3(5)-(hetero)arylpyrazoles 20-24 with modest affinity but high selectivity toward the hA(3) AR subtype. Molecular docking of the herein reported tricyclic and simplified derivatives was carried out to depict their hypothetical binding mode to our model of hA(3) receptor.
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...
Structure-Activity Relationships and Drug Design
SAR studies the intricate relationship between a drug's chemical structure and biological activity. It focuses on understanding how modifications to a drug's structure can influence its...
Cholinergic Antagonists: Chemistry and Structure-Activity Relationship
Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...

