Copper nanoparticles catalyzed carbon–heteroatom bond formation and synthesis of related heterocycles by greener procedures

A variety of procedures for the carbon–nitrogen, carbon–oxygen, carbon–sulfur and carbon–selenium bond formation using copper nanoparticles in greener conditions have been highlighted. The synthesis of several heterocyclic compounds of biological importance has also been reported using these protocols.

Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

Metal nanoparticles have been deeply studied in the last few decades due to their attractive physical and chemical properties, finding a wide range of applications in several fields. Among them, well-defined nano-structures can combine the main advantages of heterogeneous and homogeneous catalysts. Especially, catalyzed multi-step processes for the production of added-value chemicals represent straightforward synthetic methodologies, including tandem and sequential reactions that avoid the purification of intermediate compounds. In particular, palladium- and copper-based nanocatalysts are often applied, becoming a current strategy in the sustainable synthesis of fine chemicals. The rational tailoring of nanosized materials involving both those immobilized on solid supports and liquid phases and their applications in organic synthesis are herein reviewed.

Synthesis of bimetallic nanoparticles loaded on to PNIPAM hybrid microgel and their catalytic activity

This study was designed to preparecarboxyl-functionalized poly (N-isopropylacrylamide) PNIPAM microgels having excellent catalytic properties.Recently, researchers are trying to fabricate cost effective and efficient hybrid catalytic materials for the synthesis of nitrogenous compounds along with enhanced optical properties. For the same motive, synthesis of carboxyl-functionalized PNIPAM microgels was performed by using polymerization of soap-free emulsion of N-isopropyl acrylamide, which is NIPAM along with acrylic acid (AA). The thiol group was introduced through the imide bond mediated by carbodiimide, between carboxyl-functionalized microgels through carboxyl group and aminoethanethiol (AET). Copper, Palladium and Cu/Pd nanoparticles were incorporated successfully into thiol-functionalized PNIPAM microgels through metals thiol linkage. The synthesized microgels and hybrid encompassing metallic nanoparticles were characterized in detail by using Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron (XPS) and Fourier transformed infrared spectroscopy for structural interpretation. The thermal properties of the pure and hybrid microgels were inspected by TG analysis. The prepared nanocomposites PNIPAM-Cu, PNIPAM-Pd and PNIPAM-Cu/Pd exhibited decent catalytic properties for the degradation of 4-Nitrophenol and methylene blue, but the bimetallic Cu/Pd have remarkable catalytic properties. The catalytic reaction followed pseudo-first-order reaction with rate constants 0.223 min-1, 0.173 min-1 for 4-Nitrophenol and methylene blue in that order. In this study,we were able to establish that Cu/Pd hybrid is an efficient catalyst for 4-Nitrophenol and methylene blue as compared to its atomic analogue.

Recent developments in the nanomaterial-catalyzed green synthesis of structurally diverse 1,4-dihydropyridines

1,4-Dihydropyridine (1,4-DHP), a privileged heterocyclic scaffold, has been extensively utilized in various biological and therapeutic applications. In this review article, we discussed the role of different nano-catalysts, nanoflakes, nanocomposites, and other green-supported nanomaterials in the synthesis of a biologically active and vital pharmaceutical precursor 1,4-DHP and its derivatives such as polyhydroquinoline, benzopyranopyridines, and dihydropyridine since 2015. It is evident that although the use of various tailored nanostructures under different conditions to optimize the synthesis of 1,4-DHP and its compounds has provided sustainable and efficient proposals, yet the development of greener practices in the synthesis of 1,4-DHPs, which can be applied to design new synthetic routes and sequences in process development, is a far-reaching task to be accomplished.

Single pot multicomponent approaches using different nanomaterials as green catalysts for synthesis of 1,4-dihydropyridine (1,4-DHP), a privileged heterocyclic scaffold with vital biological and therapeutic applications are reviewed.

Microwave assisted one pot three component synthesis of propargylamine, tetra substituted propargylamine and pyrrolo[1,2-a]quinolines using CuNPs@ZnO–PTh as a heterogeneous catalyst

A Cu@ZnO–PTh nanocomposite was synthesized and used as a heterogeneous catalyst for KA² and A³ coupling, which is a highly efficient and green technique.

CuO@Fe2O3 catalyzed C1-alkynylation of tetrahydroisoquinolines (THIQs) via A3 coupling and its decarboxylative strategies

C1-alkynylation of tetrahydroisoquinoline (THIQ) with wide substrate scope was achieved via A3 coupling strategy from the reaction among THIQ, aldehydes and alkynes using CuO@Fe₂O₃ as a nanocatalyst under green reaction conditions.

Cu ion-exchanged and Cu nanoparticles decorated mesoporous ZSM-5 catalysts for the activation and utilization of phenylacetylene in a sustainable chemical synthesis

Highly dispersed Cu nanoparticles supported on the large external surface of Meso-ZSM-5 exhibited excellent activity in the selective synthesis of indolizines, chalcones, and triazoles using phenylacetylene as one of the building blocks.

CuI nanoparticles mediated expeditious synthesis of 2-substituted benzimidazoles using molecular oxygen as the oxidant

2-Substituted benzimidazoles from o-diaminobenzenes and aldehydes using CuI nanoparticles as a heterogeneous nano-catalyst and O₂ as an oxidant were synthesised in excellent yields.