Reusable cobalt-copper-catalyzed cross-coupling of (hetero)aryl halides with primary amides under air: investigating a new Co0/CoII-based catalytic cycle

We report an efficient ligand-free cobalt-copper-catalyzed cross-coupling reaction of aryl halides with primary amides and also investigate a new Co0/CoII-based catalytic cycle for this transformation. This reaction successfully couples a wide range of aryl and heteroaryl halides (including chlorides, bromides, and iodides) with various aryl, heteroaryl, and aliphatic primary amides in air under solvent-minimized conditions. This cost-effective method efficiently produces the desired cross-coupling products (N-arylamides) in good to excellent yields, showcasing a broad substrate scope (51 examples) and tolerance to many sensitive functional groups (including heterocycles). This protocol requires no conventional work-up and can be performed without the need for strict inert conditions. The established method is also suitable for gram-scale synthesis. Importantly, the catalyst is environmentally benign, inexpensive, and can be reused several times with insignificant loss of catalytic activity. A series of experiments, including UV spectroscopy, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and cyclic voltammetry (CV), were carried out to determine the oxidation state of the active catalytic species, and a radical clock experiment using a radical probe was conducted to examine the reaction mechanism. The experiments support the proposed novel mechanism and eliminate the possibility of a radical-based pathway.

Reusable Iron-Copper Catalyzed Cross-Coupling of Primary Amides with Aryl and Alkyl Halides: Access to N-Arylamides as Potential Antibacterial and Anticancer Agents

We present, for the first time, an efficient ligand-free iron-copper catalyzed cross-coupling reaction involving a variety of aryl, heteroaryl halides (including chlorides, bromides, and iodides), and alkyl bromides with diverse aryl and aliphatic primary amides, conducted under solvent-minimized conditions. This economically competitive protocol successfully yielded the corresponding cross-coupling products, N-arylamides and N-alkylamides, in good to excellent yields with broad substrate scope (65 examples) and tolerance to several sensitive functionalities (including heterocycles). No conventional work-up is required for this protocol, and the developed method is applicable for gram-scale synthesis. Notably, the catalyst is inexpensive, environmentally friendly, and can be reused at least four times with minimal loss of catalytic activity. A series of experiments, including X-ray photoelectron spectroscopy (XPS), UV spectroscopy, cyclic voltammetry (CV), electron paramagnetic resonance (EPR), and X-ray diffraction (XRD) were conducted to identify the oxidation state of active catalytic species and radical clock experiment was performed using a radical probe to investigate the reaction mechanism. Furthermore, we evaluated the antibacterial and anticancer properties of selected synthesized products (3 ii, 3 xii, and 3 xxxx) in-vitro. The results indicated that the prepared compounds exhibited promising antibacterial and anticancer activities (MTT and Molecular Docking).

Enhanced reduction of nitrobenzene derivatives using reusable Ni nanoparticles supported on multi-layered poly(1,2-phenylenediamine)-coated layered double hydroxides

Recently, nanomaterials with layered double hydroxide (LDH) cores have been the subject of intense research regarding their promising applications in organic synthesis. In this study, nitrobenzene reduction is investigated by designing and synthesizing a novel LDH-based heterogeneous catalyst containing a nickel-1,2-phenylenediamine complex. The Cu–Zn–Al LDH was functionalized with copolymer bearing a glycidyl methacrylate (GMA) linkage that makes it suitable for grafting with 1,2-phenylenediamine. Overall, the synthesized LDH@MPS-GMA-PDA-Ni was found to be a highly efficient heterogeneous nanocatalyst that can catalyze nitroarene reduction with high yields under mild conditions.

Preparation and characterization of Pd supported on 5-carboxyoxindole functionalized cell@Fe3O4 nanoparticles as a novel magnetic catalyst for the Heck reaction

Pd supported on 5-carboxyoxindole functionalized cell@Fe₃O₄ nanoparticles (Pd@CAI@cell@Fe₃O₄), a new magnetic nanocatalyst, was prepared and characterized using inductively coupled plasma atomic emission spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and energy-dispersive X-ray spectroscopy techniques. The synthesized nanocatalyst (Pd@CAI@cell@Fe₃O₄) was employed for Heck-type arylation of different substituted maleimides with iodoarenes in good to excellent yields. This green catalyst was easily recovered and reused several times with no substantial loss of activity, providing a clean and efficient synthetic procedure with excellent yield and reduced time.

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in "click" reactions

In recent years, many inorganic silica/carbon-based and magnetic materials have been selected to arrest copper ions through a widespread range of anchoring and embedding methodologies. These inorganic supported nanocatalysts have been found to be efficient, environmentally friendly, recyclable, and durable. In addition, one of the vital issues for expanding new, stable, and reusable catalysts is the discovery of unique catalysts. The basis and foundation of this review article is to consider the recently published developments (2014-2019) in the synthesis and catalytic applications of copper supported by silica nanocomposites, carbon nanocomposites, and magnetic nanocomposites for expanding the "click" chemistry.

Synthesis, Molecular Docking, and Preliminary Evaluation of 2-(1,2,3-Triazoyl)benzaldehydes As Multifunctional Agents for the Treatment of Alzheimer's Disease

We described here our results on the use of thiourea as a ligand in the copper catalysed azide-alkyne cycloaddition (CuAAC) of 2-azidobenzaldehyde with alkynes. Reactions were performed reacting 2-azidobenzaldehyde with a range of terminal alkynes using 10 mol % of copper iodide as a catalyst, 20 mol % of thiourea as a ligand, triethylamine as base, DMSO as solvent at 100 °C under nitrogen atmosphere. The corresponding 2-(1H-1,2,3-triazoyl)-benzaldehydes (2-TBH) were obtained in moderated to excellent yields and according our experiments, the use of thiourea decreases the formation of side products. The obtained compounds were screened for their binding affinity with multiple therapeutic targets of AD by molecular docking: β-secretase (BACE), glycogen synthase kinase (GSK-3β) and acetylcholinesterase (AChE). The three compounds with highest affinity, 5 a (2-(4-phenyl-1H-1,2,3-triazol-1-yl)benzaldehyde), 5 b (2-(4-(p-tolyl)-1H-1,2,3-triazol-1-yl)benzaldehyde), and 5 d (2-(4-(4-(tert-butyl)phenyl)-1H-1,2,3-triazol-1-yl)benzaldehyde) were selected and evaluated on its antioxidant effect, in view of select the most promising one to perform the in vivo validation. Due the antioxidant potential ally to the affinity with BACE, GSK-3β and AChE, compound 5 b was evaluated in a mouse model of AD induced by intracerebroventricular injection of streptozotocin (STZ). Our results indicate that 5 b (1 mg/kg) treatment during 20 days is able to reverse the cognitive and memory impairment induced by STZ trough the modulation of AChE activity, amyloid cascade and GSK-3β expression.

Ionically Tagged Magnetic Nanoparticles with Urea Linkers: Application for Preparation of 2-Aryl-quinoline-4-carboxylic Acids via an Anomeric-Based Oxidation Mechanism

In this exploration, we reported the design and synthesis of a novel ionically tagged magnetic nanoparticles bearing urea linkers, namely, Fe₃O₄@SiO₂@(CH₂)₃-urea-thiazole sulfonic acid chloride. The structure of the mentioned compound was fully characterized by using several techniques including Fourier transform infrared spectroscopy, energy-dispersive X-ray analysis, elemental mapping analysis, thermogravimetric analysis/differential thermal analysis, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometer. In the presence of the novel reusable catalyst, applied starting materials including aryl aldehydes, pyruvic acid, and 1-naphthylamine condensed to afford the desired 2-aryl-quinoline-4-carboxylic acid derivatives via an anomeric-based oxidation pathway under solvent-free conditions.