Green Synthetic Approach: An Efficient Eco-Friendly Tool for Synthesis of Biologically Active Oxadiazole Derivatives

Abstract

Green synthetic protocol refers to the development of processes for the sustainable production of chemicals and materials. For the synthesis of various biologically active compounds, energy-efficient and environmentally benign processes are applied, such as microwave irradiation technology, ultrasound-mediated synthesis, photo-catalysis (ultraviolet, visible and infrared irradiation), molecular sieving, grinding and milling techniques, etc. Thesemethods are considered sustainable technology and become valuable green protocol to synthesize new drug molecules as theyprovidenumerous benefits over conventional synthetic methods.Based on this concept, oxadiazole derivatives are synthesized under microwave irradiation technique to reduce the formation of byproduct so that the product yield can be increased quantitatively in less reaction time. Hence, the synthesis of drug molecules under microwave irradiation follows a green chemistry approach that employs a set of principles to minimize or remove the utilization and production of hazardous toxic materials during the design, manufacture and application of chemical substances.This approach plays a major role in controlling environmental pollution by utilizing safer solvents, catalysts, suitable reaction conditions and thereby increases the atom economy and energy efficiency. Oxadiazole is a five-membered heterocyclic compound that possesses one oxygen and two nitrogen atoms in the ring system.Oxadiazole moiety is drawing considerable interest for the development of new drug candidates with potential therapeutic activities including antibacterial, antifungal, antiviral, anticonvulsant, anticancer, antimalarial, antitubercular, anti-asthmatic, antidepressant, antidiabetic, antioxidant, antiparkinsonian, analgesic and antiinflammatory, etc. This review focuses on different synthetic approaches of oxadiazole derivatives under microwave heating method and study of their various biological activities.

A review on synthetic account of 1,2,4-oxadiazoles as anti-infective agents

“…Among these isomeric oxadiazoles, 1,2,4-oxadiazoles have found many applications in pharmaceutical industry for drug discovery, scintillating materials and dyestuff industry [ 22 ]. Oxadiazoles are also synthesized from green chemistry approach which microwave-assisted synthesis which is low cost and also they are not producing any toxic material during the preparation of oxadiazoles [ 23 ]. Following the search through Scopus using the keywords “1,2,4-oxadiazoles,” research on 1,2,4-oxadiazoles has been expanding exponentially year by year (Fig.…”

Oxadiazole: A highly versatile scaffold in drug discovery

“…The common oxadiazole‐containing medicines like raltegravir (anti‐HIV), furamizole (antibiotic), zibotentan (anticancer), tiodazosin (alpha‐adrenergic receptor antagonist), oxolamine (cough suppressant), and nesapidil (antihypertensive) available in the market are shown in Figure 5. [ 40–45 ]…”

“…The common oxadiazole-containing medicines like raltegravir (anti-HIV), furamizole (antibiotic), zibotentan (anticancer), tiodazosin (alpha-adrenergic receptor antagonist), oxolamine (cough suppressant), and nesapidil (antihypertensive) available in the market are shown in Figure 5. [40][41][42][43][44][45] Oxadiazoles have a broad-spectrum of pharmacological activities. [46] They have displayed several biological activities such as antimicrobial, [47] antihypertensive, [48] antimitotic, [49] anti-inflammatory, [50] anticancer or antiproliferative [51] F I G U R E 1 FDA-approved drugs in 2020 containing heterocyclic motifs.…”

Ultrasound-Assisted Synthesis of Fluorescent Azatetracyclic Derivatives: An Energy-Efficient Approach

“…In the recent years, ultrasound (US)-assisted reactions have become a modern and successful tool in organic and medicinal chemistry. US irradiation of organic reactions has several important advantages in terms of higher yields, increased purity of the compounds and selectivity, shorter reaction times, lower costs, and simplicity in handling and processing in comparison with conventional thermal heating (TH), being a facile alternative to several organic syntheses [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. In addition, due to milder reaction conditions, less or no side reactions, the use of small amounts of solvents, and the energy-saving nature, the reaction can be considered eco-friendly [ 9 , 10 , 11 ].…”