A Greener Synthetic Approach to Tetrazoles via Multicomponent Reactions

The synthesis of heterocyclic compounds has drawn considerable attention in the scientific community due to their existence in the majority of medicinal & pharmaceutically important compounds as well as natural products. Among them, the remarkable existence of tetrazoles has been realized in several commercially available drugs. In this regard, various synthetic protocols to access tetrazoles have been developed to address the efficiency and environmental impacts in terms of minimization of the steps, elevating yields, and conducting environmentally benign and sustainable chemistry. The management and detrimental environmental impact of waste has been recognised as a consistent concern, along with the costs associated with its disposal. Among various approaches to minimise unwanted materials from a process, one of the best alternatives is to perform a reaction in the absence of excess chemical reagents and catalysts. Other options include the reactions affected by the application of heat, light, sound, or electrolysis. The multicomponent reactions (MCR) display a unique approach establishing a step forward toward clean, step and atom-economical chemical synthesis. Most of them utilize the required substrates, eliminating the stoichiometric use of reagents, reducing the possibility of forming unwanted side products. The present review displays the concepts of MCR in the synthesis and functionalization of tetrazole, which contributes to green and sustainable chemistry.