Recently, the multicomponent reaction considers as an integral part of the Heterocyclic reactions and important method in the modern researches which are globally used in the Organic synthesis. A wide range of heterocyclic compounds has been synthesized by one-pot three-component to physiologically and pharmacologically develop active molecules 1.
Multicomponent reactions (MCRs) have emerged as powerful tools and economical procedures to prepare heterocyclic compounds. These reactions could lead to some advantages, atom economy, simplicity, high yield, ability to form carbon-heteroatom and carbon–carbon bonds with time saving under simple reaction conditions 2. A large number of literature survey reveals synthesis of Five-membered heterocyclic systems having two or three heteroatoms (N or N, S) at the symmetrical positions are known as pyrazole and thiadiazole. These compounds with its derivatives constituted a significant class of heterocyclic which were widely employed in different applications of organic synthesis field. 3,4. Thus, the development of simple reaction methods to synthesize the pyrazole-1,3,4-thiadiazoles as a single product and more interestingly functionalization of pyrazole-thiadiazole is highly desirable in the major challenging issues more than using solvents and catalysts 5.
The main disadvantages of previous methods are using more than single step, chemical reagents, solvents, heat source, acidic medium and long times, so that to avoid this problems, innovation new method have been produced to prepare these compounds in easy way with one product by using of metal nanoparticles 6. The development of new catalysts by metal nano-scale design has emerged as a fertile field for research and innovation because of the potential of increasing the efficiency and selectivity, along with the advantages of environmentally benign synthetic procedures and catalyst reusability. Nano catalysis has been considered as a very powerful and highly demanding area 7. Among the metal nanoparticles, environment-friendly and comparatively inexpensive copper nanoparticles play an important role as catalyst in the field of organic transformation and fine chemical synthesis 8. Copper nanoparticles (Cu-NPs) have been extensively explored as highly selective catalysts for the construction of C-C and C-heteroatom bonds forming reactions 9. Among them, multicomponent reactions (MCRs) performed with heterogeneous copper nanocatalysts have undergone an explosive growth in recent years 10.
MCRs can be described as processes in which three or more reactants are introduced concurrently or sequentially to form a single product which contains the essential parts of the starting materials 11. The multicomponent reactions have emerged as a common tool in modern synthetic organic chemistry. These reactions gave the facile synthesis of complicated molecules in a one-pot reaction without isolation and purification of reaction intermediates.
Consequently, lead to lower the costs, time and energy. Besides this, MCRs are modular and convergent in nature and also an important source of molecular diversity 12. The above advantages of MCRs, along with a variety of readily available cheap copper nanocatalysts, enhance the scope to generate many catalytic systems towards the synthesis of important organic compounds.
