Expanding the tetrazole space: medicinal chemistry, biological diversity and structure–activity relationships

Tetrazole, a synthetic five-membered heterocycle composed of one carbon and four nitrogen atoms, has emerged as a privileged scaffold in modern drug discovery. Despite its absence in natural products, the tetrazole ring is widely recognized for its ability to function as a bioisostere of carboxylic acid and amides, offering improved metabolic stability, enhanced binding interactions, and favorable pharmacokinetic properties. A diverse array of tetrazole-based compounds has demonstrated potent biological activity, with several already approved for clinical use and many others under active investigation. These molecules have shown promise in the treatment of various diseases, including cancer, tuberculosis, diabetes, inflammatory conditions, infectious diseases, and neurodegenerative disorders. Ongoing structure-activity relationship (SAR) studies continue to drive the optimization of tetrazole derivatives for improved efficacy and reduced toxicity. Beyond therapeutic applications, tetrazoles are also being explored in advanced materials, catalysis, and agrochemical development. This review provides a comprehensive summary of recent progress in the synthesis, biological evaluation, and therapeutic potential of tetrazole-containing compounds, highlighting their significance in the rational design of next-generation drug candidates.