Triazoles: Synthetic Strategies, Structural Elucidation, and Biological Applications
Hassan Gamal
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt.
Khadiga A. Ismail
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt and Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alalamein International University, 51718, Egypt.
Mohamed Teleb
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt.
Adnan A. Bekhit *
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt and Pharmacy Program, Allied Health Department, College of Health Sciences, University of Bahrain, P.O. Box 32038, Bahrain.
*Author to whom correspondence should be addressed.
Abstract
Triazoles are five-membered aromatic heterocycles containing three nitrogen atoms and two carbon atoms and occur principally as the 1,2,3- and 1,2,4-triazole isomers. Their physicochemical stability, capacity for hydrogen bonding and dipolar interactions, and compatibility with diverse substitution patterns have made triazoles important scaffolds in synthetic and medicinal chemistry. This narrative review summarises established and recent strategies for the synthesis of 1,2,3- and 1,2,4-triazoles, approaches used to distinguish regioisomers, and representative biological applications of triazole-containing compounds. Particular attention is given to thermal and metal-catalysed azide-alkyne cycloadditions, metal-free approaches, 1,2,4-triazole-forming reactions, anticancer, anti-inflammatory, antimicrobial, and antiviral activities, selected clinically used and investigational triazole-containing compounds, toxicity considerations, and emerging applications. The evidence is interpreted according to the level of experimental support, with computational, biochemical, cellular, animal, and clinical findings distinguished where relevant.
Keywords: Triazoles, cefatrizine, structural elucidation, anticancer, heterocyclic rings