Green Chemistry in Organic Synthesis: Recent Update on Green Catalytic Approaches in Synthesis of 1,2,4-Thiadiazoles

Abstract

Green (sustainable) chemistry provides a framework for chemists, pharmacists, medicinal chemists and chemical engineers to design processes, protocols and synthetic methodologies to make their contribution to the broad spectrum of global sustainability. Green synthetic conditions, especially catalysis, are the pillar of green chemistry. Green chemistry principles help synthetic chemists overcome the problems of conventional synthesis, such as slow reaction rates, unhealthy solvents and catalysts and the long duration of reaction completion time, and envision solutions by developing environmentally benign catalysts, green solvents, use of microwave and ultrasonic radiations, solvent-free, grinding and chemo-mechanical approaches. 1,2,4-thiadiazole is a privileged structural motif that belongs to the class of nitrogen–sulfur-containing heterocycles with diverse medicinal and pharmaceutical applications. This comprehensive review systemizes types of green solvents, green catalysts, ideal green organic synthesis characteristics and the green synthetic approaches, such as microwave irradiation, ultrasound, ionic liquids, solvent-free, metal-free conditions, green solvents and heterogeneous catalysis to construct different 1,2,4-thiadiazoles scaffolds.

Nanomagnetic CoFe2O4@SiO2-EA-H3PO4 as a zwitterionic catalyst for the synthesis of bioactive pyrazolopyranopyrimidines and dihydropyrano[2,3-c]pyrazoles

“…6,10 Green catalysis, a subset of green chemistry, emphasizes the pressing need to develop and utilize catalysts that are environmentally friendly. 12,13 In this regard, an ideal catalyst should be cost-effective, highly active, efficient, selective, stable, easily recoverable, and recyclable. 14 Moreover, hybrid organic-inorganic materials have attracted considerable attention as heterogeneous catalysts in the eld of organic synthesis.…”

Humic Acid: A Promising and Green Bioorganic Catalyst in Organic Syntheses

“…In this context, several sustainable and green approaches have been developed and used over the years for example microwave, visible light, ultrasoundassisted synthesis, grindstone chemistry, ball milling and electrochemical approach. [2,3] Thus, discovering alternative synthetic approaches involving green and sustainable aspect is always a hot topic in organic synthesis. In the reaction process, the catalyst plays a key role.…”

“…The twelve principles of green chemistry mainly emphasize on the reduced step count in chemical reactions, employing green solvents, chemicals, and catalysts, easy handling of chemicals, prevention of waste generation and utilizing green energy sources. In this context, several sustainable and green approaches have been developed and used over the years for example microwave, visible light, ultrasound‐assisted synthesis, grindstone chemistry, ball milling and electrochemical approach [2,3] . Thus, discovering alternative synthetic approaches involving green and sustainable aspect is always a hot topic in organic synthesis.…”

Synthesis of a bistriazolyl-phenanthroline–Cu(ii) complex immobilized on nanomagnetic iron oxide as a novel green catalyst for synthesis of imidazoles via annulation reactions

“…17,18 The increasing focus on green chemistry aims to replace costly, hazardous, and polluting catalysts with environmentally friendly and highly stable heterogeneous catalysts. 19 Cu-based catalysts are crucial in multicomponent reactions in organic chemistry, combining three or more reactants to produce complex molecules efficiently. 20,21 Demonstrating high efficiency and selectivity, these catalysts streamline synthesis, saving time and resources.…”

“…17,18 The increasing focus on green chemistry aims to replace costly, hazardous, and polluting catalysts with environmentally friendly and highly stable heterogeneous catalysts. 19…”