One-pot Synthesis Of Polyhydroquinoline Derivatives Research Articles

Schiff Base Complex of Copper Immobilized on Core-Shell Magnetic Nanoparticles Catalyzed One-Pot Syntheses of Polyhydroquinoline Derivatives under Mild Conditions Supported by a DFT Study.

We synthesized a stable and reusable Schiff base complex of copper immobilized on core-shell magnetic nanoparticles [Cu(II)-SB/GPTMS@SiO2@Fe3O4] with simple, efficient, and available materials. A variety of characterization analyses including Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating-sample magnetometry (VSM), energy-dispersive X-ray spectrometry (EDX), and inductively coupled plasma (ICP) confirm that our synthesized nanocatalyst was obtained. The particle size distribution from the TEM image was obtained in the range of 42-55 nm. The existence of cupric species (Cu2+) in the catalyst was determined with XPS analysis and clearly indicated two peaks at 933.7 and 953.7 eV for Cu 2p3/2 and Cu 2p1/2, respectively. BET results showed that our catalyst synthesized with a mesoporous structure and with a specific area of 48.82 m2 g-1. After detailed characterization, the resulting nanocatalyst exhibited excellent catalytic performance for the explored catalytic reactions in the one-pot synthesis of polyhydroquinoline derivatives by the Hantzsch reaction of dimedone, ethyl acetoacetate, ammonium acetate, and various aldehydes under sustainable and mild conditions. The corresponding products 5a-l are achieved in yields of 88-97%. Additionally, density functional theory (DFT) calculations were carried out to investigate the electrostatic potential root (ESP), natural bond orbital (NBO), and molecular orbitals (MOs), drawing the reaction mechanism using the total energy of the reactant and product and the study of structural parameters.

Core-shell structured Fe3O4@MgO: magnetically recyclable nanocatalyst for one-pot synthesis of polyhydroquinoline derivatives under solvent-free conditions

Core-shell structured Fe3O4@MgO: magnetically recyclable nanocatalyst for one-pot synthesis of polyhydroquinoline derivatives under solvent-free conditions

One-pot synthesis of polyhydroquinoline derivatives using nano-Fe3O4@dextrin/BF3 as a magnetic biodegradable catalyst

One-pot synthesis of polyhydroquinoline derivatives using nano-Fe3O4@dextrin/BF3 as a magnetic biodegradable catalyst

Ionic Liquid-Assisted Fabrication of Bioactive Heterogeneous Magnetic Nanocatalyst with Antioxidant and Antibacterial Activities for the Synthesis of Polyhydroquinoline Derivatives.

Antibacterial materials have obtained much attention in recent years due to the presence of hazardous agents causing oxidative stress and observation of pathogens. However, materials with antioxidant and antibacterial activities can cause toxicity due to their low biocompatibility and safety profile, urging scientists to follow new ways in the synthesis of such materials. Ionic liquids have been employed as a green and environmentally solvent for the fabrication of electrically conductive polymers. In the present study, an antibacterial poly(p-phenylenediamine)@Fe3O4 (PpPDA@Fe3O4) nanocomposite was fabricated using [HPy][HSO4] ionic liquid. The chemical preparation of PpPDA@Fe3O4 nanocomposite was initiated through the oxidative polymerization of p-phenylenediamine by ammonium persulfate in the presence of [HPy][HSO4]. The PpPDA@Fe3O4 nanocomposite exhibited antibacterial properties against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The PpPDA@Fe3O4 nanocomposite was employed as a heterogeneous nanocatalysis for one-pot synthesis of polyhydroquinoline derivatives using aromatic aldehyde, dimedone, benzyl acetoacetate, and ammonium acetate. Polyhydroquinoline derivatives were synthesized in significant yields (90–97%) without a difficult work-up procedure in short reaction times. Additionally, PpPDA@Fe3O4 nanocatalyst was recycled for at least five consecutive catalytic runs with a minor decrease in the catalytic activity. In this case, 11 derivatives of polyhydroquinoline showed in vitro antioxidant activity between 70–98%.

Cu@SB-MCM-41 composite as an efficient and recyclable nanocatalyst for the synthesis of polyhydroquinoline derivatives via unsymmetrical Hantzsch reaction

In this paper, a novel Schiff-base/copper complex containing ordered mesoporous silica (Cu@SB-MCM-41) material is synthesized, characterized and its catalytic application is investigated in the one-pot synthesis of polyhydroquinolines through the Hantzsch reaction. Cu@SB-MCM-41 nanocatalyst was characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller theory (BET), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and transmission electron microscopy (TEM). This catalyst demonstrated high performance to prepare of a set of different derivatives of polyhydroquinolines under moderate reaction conditions with short reaction times. This catalyst was effectively recovered and reused several times without an important decrease in its catalytic activity.

Synthesis and characterization of copper (II)-poly(acrylic acid)/M-MCM-41 nanocomposite as a novel mesoporous solid acid catalyst for the one-pot synthesis of polyhydroquinoline derivatives

In this study, a novel mesoporous silica nanocomposite (MSNC) based on poly(acrylic acid) and amine-functionalized MCM-41 mesoporous silica as amplification agents was constructed via an ultrasonic-assisted method as a straightforward, fast, eco-friendly and it is denoted as M-MCM-41. Then Cu (II) was immobilized on PAA/M-MCM-41 surface and the novel heterogeneous reusable catalyst was fully characterized using appropriate techniques such as Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), thermogravimetry analysis (TGA) and N2 adsorption–desorption. The resulting catalyst was successfully used for the condensation of various aromatic aldehydes, dimedone, ß-ketoester and ammonium acetate under solvent-free and mild conditions to yield polyhydroquinoline derivatives in good to excellent yields. Also, the experimental evidence was demonstrated that Cu (II)-PAA/M-MCM-41 nanocomposite could act as a recoverable and reusable nanocatalyst without a meaningful drop in the yield and the reaction time at least four times.

A Nano-sized Nd–Ag@polyoxometalate Catalyst for Catalyzing the Multicomponent Hantzsch and Biginelli Reactions

For the first time the catalytic activity of AgNdSiW11, was examined in two named reactions, namely Hantzsch and Biginelli reactions. A simple, eco-friendly and highly efficient one-pot synthesis of polyhydroquinoline derivatives via Hantzsch multicomponent reactions (MCRs) involving cyclocondensation of differently-substituted aldehydes, β-ketoesters or dimedone, active methylene compounds, and ammonium acetate as a source of nitrogen, in the presence of AgNdSiW11 as a catalyst in EtOH/H2O under reflux conditions in high yields was successfully achieved. Furthermore, the catalytic performance of AgNdSiW11 was also successfully tested in the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones via Biginelli MCR involving cyclocondensation of differently-substituted aldehydes, ethyl acetoacetate and urea as source of nitrogen in the presence of AgNdSiW11 under reflux conditions in EtOH/H2O. This prolific combination of Ln and POMs inaugurates a powerful class of catalysts for the different chemical transformations, which overcomes key limitations of previously established salts and Lewis acidic metals-based catalysts under low catalyst loading, the use of water scavengers, dry solvents and additives for facilitating the specialized experimental setups commonly employed to the organic reactions.

1, 3-Disulfonic acid imidazolium hydrogen sulphate as an efficient and reusable ionic liquid for the multicomponent synthesis of polyhydroquinoline derivatives under solvent-free conditions

A facile and highly effective one-pot synthesis of polyhydroquinoline derivatives is reported via Hantzsch condensation of aldehydes, 1,3-dicarbonyl compounds, ethyl acetoacetate, and ammonium acetate in the presence of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient and recyclable ionic liquid under solvent-free conditions. This methodology offers several advantages such as short reaction times, high yields, environmentally benign, mild reaction conditions, simple work-up procedure, and reusability of the ionic liquid.

Catalyst-free, Knoevenagel-Michael Addition Reaction of Dimedone under Microwave Irradiation: An Efficient One-pot Synthesis of Polyhydroquinoline Derivatives

Present investigation reports a concise and efficient protocol for the synthesis of polyhydroquinoline derivatives through coupling of four different components viz. aromatic aldehydes, dimedone, ethyl acetoacetate or ethyl cyanoacetate, and ammonium acetate. The same phenomenon can be observed using arylmethylene bis(3-hydroxy-2-cyclohexene-1-ones), ethyl acetoacetate, and ammonium acetate in one pot under microwave irradiation. The key advantages of the given protocol include short reaction time, high yields, and simple work-up and purification procedure. The present method also allows us to synthesize highly functionalized title compounds from simple and readily available starting materials.

Combined Thiourea Dioxide–Water: An Effective Reusable Catalyst for the Synthesis of Polyhydroquinolines via Hantzsch Multicomponent Coupling

Abstract Thiourea dioxide in water was found to be an efficient and reusable organocatalytic system for the one-pot synthesis of polyhydroquinoline derivatives via the Hantzsch-type coupling of aldehyde, dimedone, acetoacetate, and ammonium acetate under mild reaction conditions. Operational simplicity, the use of an economically affordable catalyst, environmentally benign conditions, high product yields, and reusability of the catalyst system were the advantageous features of the developed method.

FeF3 as a novel catalyst for the synthesis of polyhydroquinoline derivatives via unsymmetrical Hantzsch reaction

A facile and highly efficient one-pot synthesis of polyhydroquinoline derivatives is reported via four-component condensation reaction of aldehydes, β-keto compounds, active methylene compounds and ammonium acetate in the presence of FeF3 as a catalyst in ethanol at 75–80°C. The method offers several advantages including high yields, short reaction time, simple work-up procedure and catalyst reusability for several runs. The higher catalytic activity of FeF3 ascribed due to its high acidity, thermal stability and water tolerance. The superiority of use of FeF3 to the current process is compared with other Lewis acids, Fe-salts, fluoride sources and insights of the origin of the efficiency are discussed.

An efficient and rapid Mn(III) complex catalyzed synthesis of polyhydropyridine derivatives via Hantzsch 4 component condensation

A facile and an efficient one-pot synthesis of polyhydroquinoline derivatives in high yields using N,N′-bis (benzoylacetone) ethylenediamine manganese (III) chloride as an environmentally friendly mild Lewis acid catalyst with high catalytic activity and reusability via the Hantzsch reaction in short reaction time was reported. The reaction proceeded to completion within 5–25min in 90–97% yield. All of the obtained compounds were obtained in high purity without any use of more purification and characterized by physical and spectroscopic data.

Efficient one-pot synthesis of polyhydroquinoline derivatives using Cs2.5H0.5PW12O40 as a heterogeneous and reusable catalyst in molten salt media

Polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using Cs2.5H0.5PW12O40 as a heterogeneous and reusable catalyst. The present method uses molten salt media instead of hazardous organic solvents. The present methodology offers several advantages such as simple procedure, excellent yields, and a short reaction time.

Sulfamic Acid Catalyzed One-Pot Synthesis of Polyhydroquinolines via the Hantzsch Four Component Condensation Reaction

The synthesis of polyhydroquinoline derivatives has been achieved using catalytic amounts of green, inexpensive and environmentally benign sulfamic acid. The process is operationally simple and has good to excellent yields.

Efficient One-Pot Synthesis of Polyhydroquinoline Derivatives Using Silica Sulfuric Acid as a Heterogeneous and Reusable Catalyst Under Conventional Heating and Energy-Saving Microwave Irradiation

An efficient Hantzsch four-component condensation reaction for the synthesis of polyhydroquinoline derivatives was reported under two conditions: solvent-free conventional heating and energy-saving microwave irradiation. The process is simple and environmentally benign, and the use of a heterogeneous and reusable catalyst, high yields, and short reaction times are the key features of this protocol.

Nickel nanoparticle-catalyzed facile and efficient one-pot synthesis of polyhydroquinoline derivatives via Hantzsch condensation under solvent-free conditions

Polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized Nickel (Ni) as a heterogeneous catalyst. The present method does not involve any hazardous organic solvents or catalysts. The smaller size of Ni (80 ± 0.5 nm) having a higher surface to volume ratio has promising features for the reaction response such as the shortest reaction time, excellent product yields, simple work-up procedure, and purification of products by non-chromatographic methods.

An efficient, catalyst- and solvent-free, four-component, and one-pot synthesis of polyhydroquinolines on grinding

An efficient synthesis of polyhydroquinolines is achieved via a four-component reaction of aldehydes, dimedone, active methylene compounds, and ammonium acetate in one-pot under solvent-free conditions at room temperature on grinding. The present method does not involve any hazardous organic solvent or catalyst. The key advantages are the short reaction time, high yields, simple workup, and purification of products by non-chromatographic methods, i.e., by simple recrystallization from ethanol.

K 7[PW 11CoO 40]-catalyzed one-pot synthesis of polyhydroquinoline derivatives via the Hantzsch three component condensation

The synthesis of various polyhydroquinoline derivatives has been achieved using catalytic amounts of green, inexpensive and eco-friendly Keggin type heteropolyacid. The products were obtained in high yields.

An efficient one-pot synthesis of polyhydroquinoline derivatives through the Hantzsch four component condensation

A straightforward and general method has been developed for the synthesis of polyhydroquinolines derivatives by simply combining aldehyde, ethyl acetoacetate, dimedone, and ammonium acetate in the presence of a catalytic amount of scandium triflate. This method is very easy, rapid, and high yielding reaction for the synthesis of polyhydroquinolines.

An efficient one-pot synthesis of polyhydroquinoline derivatives via Hantzsch condensation using heterogeneous catalyst under solvent-free conditions

An efficient Hantzsch condensation of polyhydroquinoline derivatives was reported via a four- component coupling reaction of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of HClO4-SiO2 under solvent-free conditions. Operational simplicity, use of an economically convenient catalyst, high yield, short reaction times are the key features of this protocol.