Three-component Coupling Reaction Of Aldehydes Research Articles

Yolk-Shell Au NPs@Carbon Porous Nanoreactors Derived from ZIF-8: A High-Efficiency Catalyst for Three-Component Coupling Reaction.

A yolk-shell Au NPs@carbon porous nanoreactor with an active gold (Au) core and a porous carbon shell has been fabricated and demonstrates excellent high activity and cyclic stability as a heterogeneous catalyst for the three-component coupling reaction of aldehyde, amine, and alkyne. Remarkably, the unique yolk-shell nanostructure can protect gold nanoparticles (Au NPs) from aggregation, allow for efficient mass transport, and benefit substrate enrichment, giving rise to enhanced activity, stability, and recyclability.

Insights into the Three-Component Coupling Reactions of Aldehydes, Alkynes, and Amines Catalyzed by N-heterocyclic Carbene Silver: A DFT Study

Density functional theory (DFT) was used to investigate the three-component coupling reactions of aldehydes, alkynes, and amines (A3 coupling) using N-heterocyclic carbene silver as the catalyst. This study reveals that the addition reaction between the catalyst N-heterocyclic carbene silver and phenylacetylene (PAE) forms Ag_PAE. Subsequently, one hydrogen atom of the Ag_PAE migrates to the nitrogen atom of the Amine. Thereafter, the amine aldehyde condensation reaction generates a molecule of water and an imine ion with (Path one) or without (Path two) another amine catalyst. Path one has a lower reaction barrier than Path two. Subsequently, the imine ion reacts with silver phenylacetylide to generate the A3 coupling reaction product propargylamine (PPA). Furthermore, the triple bond and −N3 group in PPA undergo a cycloaddition reaction and generate the final product (PR). The entire reaction is strongly exothermic, and, therefore, the reaction is easy to conduct. Moreover, conceptual density functional theory calculations confirm the reaction mechanism. Investigating the mechanism of these reactions will be helpful for understanding and developing new synthesis strategies for similar functional compounds.

Clean Synthesis of Propargylamines Using Novel Magnetically Recyclable Silver Nanocatalyst (AgMNPs)

A novel and green magnetic nanocatalyst were synthesized by anchoring silver (I) to (2-iminomethyl)pyridine moiety. The prepared nanocatalyst was identified by different techniques, such as FT-IR, XRD, SEM, EDX, VSM, and TGA analyses. The nanocatalyst exhibited significant catalytic activity and recoverability in a three-component coupling reaction of aldehyde, amine, and terminal alkyne to produce a variety of propargylmines. This impactful method furnished the desired products under mild reaction conditions, in excellent yield (91–98%) and lower reaction time (25–45 min). The nanocatalyst was easily recovered by an external magnet and reused in10 consecutive cycles without a considerable decrease in its activity and selectivity.

Synthesis of N-protected 1-aminoalkylphosphonium salts—a new perspective

The current study presents two novel and efficient strategies for the synthesis of N-protected 1-aminoalkylphosphonium salts from readily available substrates. The first one is a one-pot methodology which is based on the three-component coupling reaction of aldehydes with amides, carbamates, lactams, imides, or urea in the presence of triarylphosphonium salt. This approach results in the production of a wide range of structurally diverse N-protected 1-aminoalkylphosphonium salts. The second one is a step-by-step procedure which results in the synthesis of N-protected 1-aminomethylphosphonium salts only, and hence has a limited scope of application. This method is performed in two steps: transformation of amide-type substrates to the corresponding hydroxymethyl derivatives and substitution of the hydroxyl group with triarylphosphine. Both protocols are promising alternatives and complement the hitherto described methodologies.

Dinuclear silver-bis(N-heterocyclic carbene) complexes: Synthesis, catalytic activity in propargylamine formation and computational studies

Preparation of a series of 1,1′-dialkyl-3,3′-(2-methylenepropane-1,3-diyl)dibenzimidazolium salts (alkyl = ethyl, propyl, butyl) (2a-2c) and their dinuclear bis(N-heterocyclic carbene) silver complexes (3a-3c) is reported. The silver complexes were synthesized via in situ deprotonation with Ag2O in 67-74% yields. The structural definitions of the synthesized compounds were performed by 1H NMR, 13C NMR, elemental analysis, FT-IR and also LC-MSMS techniques (only for 3a-3c). The silver complexes were utilized for three-component coupling reactions of aldehydes, amines and alkynes (A3-coupling). It was found that increasing the chain length of the alkyl substituent on the N-heterocyclic carbene ligand led to increase in catalytic performance. 3c showed the highest activity with 81% yield and with TON of 27 for N,N-diethyl-3-phenylprop-2-yn-1-amine formation. Geometry optimization was performed and geometric parameters were calculated for the compounds. The theoretical harmonic vibration frequencies of molecules were computed by DFT/B3LYP methods for their optimized geometries.

Silver–N‐heterocyclic carbene complexes‐catalyzed multicomponent reactions: Synthesis, spectroscopic characterization, density functional theory calculations, and antibacterial study

Nowadays, silver-N-heterocyclic carbene (silver-NHCs) complexes are widely used in medicinal chemistry due to their low toxic nature toward humans. Due to the success of silver-NHCs in medicinal applications, interest in these compounds is rapidly increasing. Therefore, the interaction of N,N-disubstituted benzimidazolium salts with Ag2 O in dichloromethane to prepare novel Ag(I)-NHCs complexes was carried out at room temperature for 120 h in the absence of light. The obtained complexes were identified and characterized by 1 H and 13 C nuclear magnetic resonance, Fourier-transform infrared, UV-Vis, and elemental analysis techniques. Then, the silver complexes were applied for three-component coupling reactions of aldehydes, amines, and alkynes. The effect of changing the alkyl substituent on the NHCs ligand on the catalytic performance was investigated. In addition, it has been found that the complexes are antimicrobially active and show higher activity than the free ligand. The silver-carbene complexes showed antimicrobial activity against specified microorganisms with MIC values between 0.24 and 62.5 μg/ml. These results showed that the silver-NHC complexes exhibit an effective antimicrobial activity against bacterial and fungal strains. A density functional theory calculation study was performed to identify the stability of the obtained complexes. All geometries were optimized employing an effective core potential basis, such as LANL2DZ for the Ag atom and 6-311+G(d,p) for all the other atoms in the gas phase. Electrostatic potential surfaces and LUMO-HOMO energy were computed. Transition energies and excited-state structures were obtained from the time-dependent density functional theory calculations.

Nickel-Catalyzed Carboalkenylation of 1,3-Dienes with Aldehydes and Alkenylzirconium Reagents: Access to Skipped Dienes.

A regio- and stereoselective nickel-catalyzed three-component coupling reaction of aldehydes, 1,3-dienes, and alkenylzirconium reagents was realized. The ligand- and additive-free protocol afforded a convenient approach to the synthesis of skipped diene compounds bearing various functionals (e.g., hydroxyl, carbonyl, halide) and heterocyclic groups. The products were readily transformed into structurally diverse polyenes. The utility of this reaction was also demonstrated by the one-pot operation and scale-up preparation.

Preparation of Ag2S Nanoparticles and using as Catalyst for the A3-coupling (Aldehyde-Amine-Alkyne) Reaction

Microwave assisted facile one-step approach was adopted to prepare mono-dispersed silver sulfide nanoparticles. The structures of the synthesized Ag2S nanoparticles were confirmed by Fourier-transform infrared spectroscopy (FT-IR), diffuse reflectance UV-vis spectroscopy (DRS), X-ray diffractometer (XRD), energy dispersive X-ray analysis (EDX) and transmission electron microscope (TEM). The prepared Ag2S nanoparticles (NPs) were successfully used as a heterogeneous catalyst in the one-pot three-component coupling reaction of aldehydes, amines and alkynes (A3-coupling) toward propargylamines. In this protocol, both aromatic and aliphatic aldehydes and secondary amines were reacted with terminal alkynes in the presence of Ag2S NPs at low catalytic loading (0.5 mol %) that led to the rapid and efficient formation of propargylamines with good to excellent yields. The A3-coupling reaction occurred effectively at 80 oC under solvent-free conditions. The catalyst is easy to prepare and is perfectly stable under the reaction conditions. Also, the Ag2S NPs catalyst can be easily recovered and reused several times and exhibited higher catalytic activity than other some commercially catalysts.

One-pot three-component synthesis of α-amino nitriles using ZnO as a heterogeneous, reusable, and eco-friendly catalyst

Various forms of α-amino nitrile molecules are found to exert strong impacts on the synthesis of multiple organic compounds such as pharmaceuticals, amino acids, agrochemical agents, and pesticides. Spherical ZnO nanoparticles (NPs) prepared by a simple co-precipitation method are an efficient heterogeneous catalyst for the synthesis of vital intermediate α-amino nitriles. The present protocol was investigated via one-pot synthesis of α-amino nitriles over ZnO NPs using a three-component coupling reaction of aldehydes, amines, and trimethylsilyl cyanide in acetonitrile. The feasibility of our synthesis approach was assessed with respect to the purity and yield of synthesized products in relation to several controlling variables (e.g., ZnO molar ratio, reaction time, amines/aldehydes types, and solvent). The qualitative characteristics of α-amino nitrile products were evaluated by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), and mass spectroscopic analysis. A high yield (81–95%) of pure α-amino nitriles within a short reaction time (45–75 min) along with good recyclability of the catalyst (e.g., without significant loss in performance over five cycles) was confirmed as the distinctive merits of this new eco-friendly synthetic method. This study confirms that various amines including sterically crowded secondary amines should react efficiently with benzenoid plus non-benzenoid aldehyde to yield α-amino nitriles. The selected route is very fast as well as economical. Hence, this method can be used for large-scale production of a variety of biologically important molecules through α-amino nitriles.

Anchorage of Au3+ into Modified Isoreticular Metal\u2013Organic Framework-3 as a Heterogeneous Catalyst for the Synthesis of Propargylamines

Postsynthetic modification of metal-organic framework is a general and practical approach to access MOF-based catalysts bearing multiple active sites. The isoreticular metal–organic framework-3 (IRMOF-3) was modified with lactic acid through condensation reaction of the carboxyl group of lactic acid and amino group present in IRMOF-3 frameworks. Au3+ was subsequently anchored onto the metal–organic framework IRMOF-3 using postsynthetic modification. The synthezized IRMOF-3-LA-Au (LA = lactic acid) was characterized by powder X-ray diffraction, N2 adsorption-desorption, infrared spectroscopy, liquid-state nuclear magnetic resonance, thermogravimetric analysis, H2-temperature programmed reduction, transmission electro microscopy, and inductively coupled plasma–optical emission spectrometry. IRMOF-3-LA-Au acted as an efficient heterogeneous catalyst in the synthesis of propargylamines by three-component coupling reaction of aldehyde, alkyne, and amine. Moreover, the catalyst is applicable to various substituted substrates, including aromatic and aliphatic aldehydes, alkyl- and aryl-substituted terminal alkynes, and alicyclic amines. In addition, the catalyst can be easily separated from the mixture and can be reused for four consecutive cycles.

Synthesis, Characterization and Recyclable Cerium Loaded CuO Nanocatalyst for the Synthesis of 1, 4- Disubstituted 1, 2, 3-Triazoles and Propargylamines

Cerium loaded CuO nanoparticles (Ce-CuO NPs) were successfully synthesized by a precipitation-thermal decomposition method. The synthesized Ce-CuO NPs were used as a nanocatalyst for the synthesis of 1, 4-disubstituted-1, 2, 3-triazoles by the click reaction of substituted benzyl azides and alkynes and synthesis of propargylamines via a three-component coupling reaction of aldehydes, alkynes and amines under ultrasonication. One-pot operation, atom-economical nature, regioselectivity and good yields are the significant features of this protocol. The reusability of the prepared nanocatalyst was successfully examined six times without any appreciable loss in catalytic activity. Synthesized compounds were characterized by 1H NMR, 13C NMR and mass spectral studies.

Synthesis, post-modification and catalytic properties of metal-organic framework NH2-MIL-53(Al)

A postsynthetic modification method was used to prepare salicylaldehyde functionalized metal-organic frameworks through the nucleophilic addition of salicylaldehyde with the amine group present in the frameworks of NH2-MIL-53(Al). Hydroxyl groups were successfully grafted onto NH2-MIL-53(Al), and imine groups were formed. Importantly, these hydroxyl and imine groups of the resulting NH2-MIL-53(Al)-SA can be used as the anchoring group to stabilise Au3+ ions and Au0 nanoparticles(NPs). By doing this, Au3+ ions and Au0 NPs were successfully encapsulated in the cages of NH2-MIL-53(Al) by a simple impregnation method. The resulting gold functionalized NH2-MIL-53(Al) showed good catalytic activities in the one-pot synthesis of structurally divergent propargylamines by three-component coupling reactions of aldehydes, amines and alkynes. Various aromatic/aliphatic aldehydes, aromatic alkynes, and piperidine were able to undergo three-component coupling on NH2-MIL-53(Al)-Au. In addition, the catalyst NH2-MIL-53(Al)-Au was recovered easily by centrifugation and reused up to four times. Thus, it can be used for the environmentally friendly synthesis of propargylamines.

Polyacrylonitrile Fiber Supported N-Heterocyclic Carbene Ag(I) As Efficient Catalysts for Three-Component Coupling and Intramolecular 1,3-Dipolar Cycloaddition Reactions under Flow Conditions

A series of recoverable and reusable N-heterocyclic carbene silver complexes supported on polyacrylonitrile fiber were prepared and characterized. Their catalytic performances in three-component coupling reactions of aldehydes, amines, and alkynes (A3 coupling) to synthesize propargylamines were evaluated. The catalysts were also used to prepare fused triazoles in one-pot reactions with excellent yields and diastereoselectivities. In these reactions, the substrates underwent A3 coupling followed by intramolecular 1,3-dipolar cycloaddition. The above reactions were also successfully performed in a continuous-flow process, and sustainable, modular, and efficient syntheses of propargylamines and fused triazoles were achieved.

Au3+/Au⁰ Supported on Chromium(III) Terephthalate Metal Organic Framework (MIL-101) as an Efficient Heterogeneous Catalystfor Three-Component Coupling Synthesis of Propargylamines.

Post-synthesis modification is a useful method for the functionalization of metal–organic frameworks (MOFs). A novel catalyst Au@MIL-101-ED-SA (ED = ethylenediamine, SA = salicylaldehyde), containing coexisting Au3+ ions and Au0 nanoparticles, was prepared successfully by post-synthesis modification with ethylenediamine, salicylaldehyde and gold. Gold nanoparticles supported on MIL-101 (Au@MIL-101) were prepared successfully by the impregnation method. Au@MIL-101-ED-SA and Au@MIL-101 were characterized by N2 adsorption–desorption, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and inductively coupled plasma-optical emission spectrometry. Au@MIL-101-ED-SA and Au@MIL-101 were applied as environmentally friendly catalysts in the three-component coupling reaction of aldehydes, amines, and alkynes for the preparation of diverse propargylamines. Au@MIL-101-ED-SA contained a fraction of cationic gold (Au3+/Au0 = 0.9) and showed higher catalytic activity than Au@MIL-101, which was prepared by the impregnation method. Furthermore, the reactions were performed under heterogeneous conditions and the novel catalyst was successfully recycled for four consecutive runs.

Palladium(II) pyridoxal thiosemicarbazone complexes as efficient and recyclable catalyst for the synthesis of propargylamines by a three‐component coupling reactions in ionic liquids

The palladium(II) complexes (1 and 2) were obtained from the reaction of [PdCl2(PPh3)2] with the tridentate Schiff base ligands, pyridoxal thiosemicarbazone (L1), and pyridoxal N-methyl thiosemicarbazone (L2), respectively in ethanol. These complexes were characterized by elemental analyses, IR, UV–Vis, 1H NMR, 31P NMR and ESI-MS spectroscopy. The molecular structure of the complex [Pd(L2)PPh3] (2) was determined by single-crystal X-ray diffraction, which reveals a distorted square planar geometry around palladium(II) ion. To screen the catalytic properties of the synthesized complexes, palladium(II) complex catalyzed three-component coupling reaction of aldehydes, amines and phenylacetylenes under solvent free conditions in ionic liquid at 80°C were done to synthesize propargylamines in high yields. The effect of solvent, time, temperature, catalyst loading and substituent on ligand moiety on the reaction was also studied. The results showed that the supported catalyst with low loading (1.0mol%) showed high stability, which could be recovered also and reused for minimum 5 times without significant loss of its activity.

Catalytic activity of N-heterocyclic carbene silver complexes derived from imidazole ligands

ABSTRACTThe N-heterocyclic carbene (NHC)-silver(I) complexes, 3a–c of the type (NHC)AgCl were prepared from 1-(methyl)-3-(alkyl)-imidazolium chlorides (2a–c) by the reactions with Ag2O in dichloromethane as a solvent at room temperature. The complexes were characterized by elemental analyses and NMR spectroscopy. The catalytic activities of NHC-silver complexes were investigated in the three-component coupling reaction of aldehyde, alkyne, and amine to propargylamines.

Supported Au/MIL-53(Al): a reusable green solid catalyst for the three-component coupling reaction of aldehyde, alkyne, and amine

MIL-53(Al) was synthesized in a mixture of aluminum nitrate, 1,4-benzenedicarboxylic acid, and water using the hydrothermal and reflux methods. A metal–organic-framework-supported Au-based heterogeneous catalyst (Au/MIL-53(Al)) was prepared using the impregnation method under mild conditions with HAuCl4·4H2O as the Au precursors. The physicochemical properties of the samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG), transmission electron microscopy (TEM), and inductively coupled plasma atomic emission spectroscopy (ICP–AES). MIL-53(Al) indicates excellent chemical stability without structure degradation during the loading and catalysis process. The XPS spectra indicate that the catalyst Au/MIL-53(Al) contains coexisting Au0 and Au3+ ions. The catalytic performance of the catalyst was examined in one-pot synthesis of structurally divergent propargylamines via three component coupling of aldehyde, alkyne, and amine (A3) in 1,4-dioxane. The results showed that the catalyst Au/MIL-53(Al) displayed high activity without any additives or an inert atmosphere (the yield reached 97.9 % for 5 h at 120 °C). Au/MIL-53(Al) has proven to be applicable to a wide range of substrates. Various aromatic/aliphatic aldehydes, aromatic alkynes, and piperidine were able to undergo A3 coupling on the catalyst Au/MIL-53(Al). In addition, the catalyst could be recovered easily by centrifugation and reused three times.

Ag(I) complexes of benzimidazol-2-ylidene ligands: a study of catalytic efficiency towards three-component coupling reactions

The $N$-heterocyclic carbene (NHC)--Ag(I) complexes 3a-c were synthesized from benzimidazolium chlorides (2a-c = NHC.HCl), incorporating benzyl derivatives and a 2-methoxyethyl group (a: $^{3}$N = 2,4,6-trimethylbenzyl; b: $^{3}$N = 2,3,5,6-tetramethylbenzyl; c: $^{3}$N = pentamethylbenzyl). The compounds were characterized by spectroscopic and elemental analyses. The synthesized NHC-Ag(I) complexes (3a-c) were tested as catalysts for the catalytic three-component coupling reaction of aldehyde, alkyne, and amine to propargylamines in various solvents. All complexes were active catalysts for catalytic three-component coupling reactions with good yields under neat and mild conditions (after 4 h, yields of up to 94%).

One-Pot Preparation of Propargylamines Catalyzed by Heterogeneous Copper Catalyst Supported on Periodic Mesoporous Organosilica with Ionic Liquid Framework.

Copper supported on periodic mesoporous organosilica (PMO) with alkylimidazolium frameworks is a highly efficient and recoverable catalyst for the preparation of propargylamines through the three-component coupling reaction of aldehydes, alkynes, and amines. The new catalyst is characterized using N2 adsorption/desorption analysis, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT-IR), and elemental analysis. The catalyst is easily recovered by a simple filtration process and subsequently reused in the seven reaction cycles without any loss of catalytic activity.

ChemInform Abstract: Polymer‐Anchored Copper(II) Complex: An Efficient Reusable Catalyst for the Synthesis of Propargylamines

Abstractvia a three‐component coupling reaction