Nano–Mn‐[4‐nitrophenyl‐salicylaldimine‐methyl pyranopyrazole]Cl2 as a new nanostructured Schiff base complex and catalyst for the synthesis of hexahydroquinolines

By the reaction of 4‐nitrobenzaldehyde with ethyl acetoacetate, malononitrile and hydrazine hydrate, pyranopyrazole derivative as an active biological compound was synthsized and then reacted with salicylaldehyde and MnCl₂.4H₂O to afford nano‐Mn‐[4‐nitrophenyl‐salicylaldimine‐methyl pyranopyrazole]Cl₂ (nano‐[Mn‐4NSMP]Cl₂) for the first time. The produced Schiff base complex with nanostructured was fully characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG) and scanning electron microscope (SEM) and used it as an efficient catalyst for the preparation of hexahydroquinolines.     

Preparation and characterization of Cu (II) supported on poly(8‐hydroxyquinoline‐p‐styrene sulphonate) and its application as catalyst for the synthesis of hexahydroquinolines

Cu ( II ) supported on poly(8‐hydroxyquinoline‐p‐styrenesulfonate) (Cu ( II )@PHQSS) was prepared and fully characterized by the different techniques including fourier transform infrared spectroscopy (FT‐IR), ¹H NMR, ¹³C NMR, thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG), differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersive X‐ray analysis (EDS). Afterward, the Cu ( II )@PHQSS as nanostructured catalyst was used as catalyst for the synthesis of hexahydroquinolines.     

Fe3O4@SiO2–ZrCl2‐MNPs: A novel magnetic catalyst for the clean and efficient cascade synthesis of 1‐(benzothiazolylamino)methyl‐2‐naphthol derivatives in the absence of solvent

A green, simple and eco‐friendly three‐component condensation for the synthesis of 1‐(benzothiazolylamino)methyl‐2‐naphthols using new magnetic nanoparticles formulated as Fe₃O₄@SiO₂–ZrCl₂‐MNPs is described. Considering the economic and environmental aspects, the method provides some advantages such as clean procedure, solvent‐free conditions, simple operation and work‐up, relatively short reaction times and high yields of the products. Moreover the introduced catalyst can be readily recovered up to 4 consecutive runs with consistent activity using an external magnet.     

CoAl2O4/Al2O3载体对钴基费托催化剂反应性能影响的研究

通过浸渍和高温焙烧,制得表面附着CoAl₂O₄微晶颗粒的改性Al₂O₃载体,并采用等体积浸渍法制备负载型Co基催化剂。结合 N₂物理吸附、XRD、H₂-TPR、XPS及H₂化学吸附等表征手段,研究改性载体及其负载钴基催化剂的织构特征;采用费托合成反应评价其催化性能。结果表明,Al₂O₃改性后,表面CoAl₂O₄的存在有效减少了载体与活性组分Co的相互作用,显著提高了催化剂的还原度和催化活性。载体的改性量在20%左右达到最佳值,继续增加,催化剂还原度和活性基本不再升高。载体改性促使催化剂CH₄选择性有所降低,C₅₊选择性略有提高。     

Hydrothermal preparation and characterization of ZnFe2O4 magnetic nanoparticles as an efficient heterogeneous catalyst for the synthesis of multi‐substituted imidazoles and study of their anti‐inflammatory activity

Nanoparticles are key focus of research for a wide range of novel applications. As such, ZnFe₂O₄ magnetic nanoparticles were synthesized hydrothermally and characterized via scanning and transmission electron microscopies, powder X‐ray diffraction, energy‐dispersive X‐ray and infrared spectroscopies, thermogravimetric analysis and magnetic measurements. They were used as a robust catalyst for the synthesis of a series of biologically active multi‐substituted imidazoles using a multicomponent reaction by the reaction of benzil with various aromatic aldehydes, ammonium acetate and aliphatic amines (N,N‐dimethyl‐1,3‐propanediamine and 1‐amino‐2‐propanol) under solvent‐free conditions. The key advantages of this method are shorter reaction times, very high yield and ease of operation. The thermally and chemically stable, benign and economical catalyst was easily recovered using an external magnet and reused in at least five successive runs without an appreciable loss of activity. All of these novel synthesized compounds were characterized from spectral data and their purities were checked using thin‐layer chromatography, giving one spot. Furthermore, the prepared compounds were tested for their anti‐inflammatory activity.     

Equisetum arvense As an abundant source of silica nanoparticles. SiO2/H3PW12O40 nanohybrid material as an efficient and environmental benign catalyst in the synthesis of 2‐amino‐4H‐chromenes under solvent‐free conditions

Uniform SiO₂ nanoparticles were successfully prepared from Equisetum arvense obtained from the north‐east of Iran. Then, surface modification of the extracted nanoparticles was performed with a methanol solution of H₃PW₁₂O₄₀ via wet impregnation method. The prepared nanocatalyst was characterized by XRD, FESEM, ICP, UV–Vis, and FT‐IR spectroscopy. The supported heterogeneous nanocatalyst was successfully applied as a Lewis/Bronsted acid catalyst in the synthesis of a series of substituted 4H–chromenes via condensation of aromatic aldehydes, malononitrile, and 4‐hydroxycoumarin under solventless conditions with fine yields in appropriately short times.     

无溶剂条件下利用微波促进下的多组分反应对2,6-二芳基-4-苯乙烯基吡啶化合物进行非预期的绿色简易合成

在无溶剂条件下,通过微波促进下的3-芳基丙烯醛肟、1-芳基乙酮及醋酸铵的多组分反应,非预期地实现了2,6-二芳基-4-苯乙烯基吡啶化合物的绿色简易合成。该方法具有环境友好、反应时间短、产率高、成本低、操作简便以及适用范围广等优点。     

Novel CuFe2O4@SiO2‐OP2O5H magnetic nanoparticles: Preparation,characterization and first catalytic application to the synthesis of 1,8‐dioxo‐octahydroxanthenes

New functionalized magnetic core–shell nanoparticles, CuFe₂O₄@SiO₂‐OP₂O₅H, were prepared by grafting of phosphorus pentoxide on CuFe₂O₄@SiO₂ nanoparticles and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray analysis, inductively coupled plasma optical emission spectrometry and vibrating sample magnetometry. The catalytic activity of CuFe₂O₄@SiO₂‐OP₂O₅H as a novel catalyst was evaluated in the synthesis of 1,8‐dioxo‐octahydroxanthenes under solvent‐free conditions. The results showed that the catalyst has high activity and the desired products are obtained in high yields within short reaction times. The catalyst is readily recovered using magnetic decantation and can be used at least four times without noticeable deterioration in catalytic activity.     

Preparation and characterization of Fe3O4@SiO2/APTPOSS core–shell composite nanomagnetics as a novel family of reusable catalysts and their application in the one‐pot synthesis of 1,3‐thiazolidin‐4‐one derivatives

Octakis[3‐(3‐aminopropyltriethoxysilane)propyl]octasilsesquioxane (APTPOSS) as a polyhedral oligomeric silsesquioxane derivative was prepared and used as a pioneer reagent to obtain a novel core–shell composite using magnetic iron oxide nanoparticles as the core and the inorganic–organic hybrid polyhedral oligomeric silsesquioxane as the shell. Fe₃O₄@SiO₂/APTPOSS were confirmed using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, dynamic light scattering, thermogravimetric analysis, X‐ray diffraction and vibrating sample magnetometry. The inorganic–organic hybrid polyhedral oligomeric silsesquioxane magnetic nanoparticles were used as an efficient new heterogeneous catalyst for the one‐pot three‐component synthesis of 1,3‐thiazolidin‐4‐ones under solvent‐free conditions. Moreover, these nanoparticles could be easily separated using an external magnet and then reused several times without significant loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation,characterization and catalytic application of molybdenum Schiff‐base complex immobilized on silica‐coated Fe3O4 as a reusable catalyst for the synthesis of pyranopyrazole derivatives

A recoverable molybdenum Schiff‐base complex immobilized on silica‐coated Fe₃O₄ nanoparticles was prepared and characterized. This superparamagntic nanocatalyst, which is separable using an external magnet, can be used as an efficient catalyst for the promotion of the synthesis of pyranopyrazole derivatives. A variety of desired products were obtained in high to excellent yields within short times. In comparison with other catalysts employed in the condensation of various aromatic aldehydes, malononitrile and 3‐methyl‐1‐phenyl‐2‐ pyrazoline‐5‐one, the present catalyst showed a much higher activity in terms of mild conditions and short reaction time. The catalyst can be reused for several times without significant loss of activity.     

Synthesis and characterization of the novel diamine‐functionalized Fe3O4@SiO2 nanocatalyst and its application for one‐pot three‐component synthesis of chromenes

Fe₃O₄@SiO₂@propyltriethoxysilane@o‐phenylendiamine as an environmentally‐benign functionalized silica‐coated magnetic organometallic nanomaterial has been synthesized and characterized by Fourier transforms infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM) images and energy dispersive X‐ray (EDX) and vibrating sample magnetometer (VSM) analyses. Then, its catalytic activity was investigated for the one‐pot three‐component condensation reaction between dimedone, malononitrile and various substituted aromatic aldehydes to afford the corresponding 2‐amino‐4H‐chromene derivatives under mild reaction conditions. This nanocatalyst can be easily recovered from the reaction mixture by using a magnet and reused for at least five times without significant decrease in catalytic activity.     

A green and efficient method for synthesis of benzimidazoles using nano‐Fe3O4 in PEG‐400/H2O aqueous system under ambient conditions at room temperature

In this paper, a green and facile protocol was described which was efficient for synthesis of benzimidazoles using nano‐Fe₃O₄ catalyst with continuous bubbling of air as the oxidant in PEG‐400/H₂O aqueous system at room temperature. This protocol afforded the target products in good to excellent yields and the catalytic system could be recycled and reused without significant loss of catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

MNPs@SiO2‐Pr‐AP: A new catalyst for the synthesis of 2‐amino‐4‐aryl thiazole derivatives

A simple and efficient synthesis of 2‐amino‐4‐aryl thiazole derivatives was carried out through the reaction of substituted acetophenones and thiourea using three different types of catalytic systems including N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide [TBBDA], poly(N,N′‐dibromo‐N‐ethylbenzene‐1,3‐disulfonamide) [PBBS] and a combination of TBBDA and nano‐magnetic catalyst supported with functionalized 4‐amino‐pyridine silica (MNPs@SiO₂‐Pr‐AP). The results showed that the use of TBBDA along with the MNPs@SiO₂‐Pr‐AP gains the highest yields of the products in the shortest reaction time.     

Polypyrrole/Fe3O4/CNT as a recyclable and highly efficient catalyst for one‐pot three‐component synthesis of pyran derivatives

Polypyrrole (PPY)/Fe₃O₄/CNT has been synthesized and characterized by FT‐IR, TEM and SEM techniques and its catalytic activity has been evaluated in the synthesis of several series of pyran derivatives. Tetrahydrobenzo[b]pyranes, 4H‐pyran‐3‐carboxylates, 4H,5H‐pyrano[3,2‐c]chromenes and dihydropyrano[2,3‐c]pyrazoles have been successfully prepared from one‐pot three‐component condensation of aldehyde, malononitrile and active methylene‐containing compounds (dimedone /ethyl acetoacetate/4‐hydroxycoumarin/3‐methyl‐2‐pyrazoline‐5‐one) using PPY/Fe₃O₄/CNT as a new and reusable heterogeneous catalyst. The present method offer several advantages such as; high yields of products, short reaction times, easy work‐up procedure and easy separation of the catalyst from the reaction mixture due to its magnetic character. Furthermore, chemoselective synthesis of bis‐benzo[b]pyran from terephthalaldehyde can be achieved by this method.     

Nanocrystalline TiO2, via green combustion synthesis,as an efficient and reusable catalyst for the preparation of 1,8‐dioxooctahydroxanthenes and 1,8‐dioxodecahydroacridines

Nanocrystalline TiO₂ is synthesized using a green combustion method and used as a recyclable catalyst for the one‐pot multicomponent synthesis of 1,8‐dioxodecahydroacridines and 1,8‐dioxooctahydroxanthenes, under solvent‐free conditions. This method is mild, environmentally friendly, inexpensive and highly effective for obtaining good to excellent yields of the products. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,characterization, and catalytic application of Fe3O4‐Si‐[CH2]3‐N=CH‐aryl for the efficient synthesis of novel poly‐substituted pyridines

Fe₃O₄ magnetic nanoparticles (MNPs) were functionalized by aminopropylsilane and reacted with aromatic aldehyde, and Fe₃O₄‐Si‐[CH₂]₃‐N=CH‐Aryl and Fe₃O₄‐Si‐(CH₂)₃‐NH‐CH₂‐Aryl MNPs were prepared as novel magnetic nanocatalysts. Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), and scanning and transmission electron microscopy (SEM and TEM) were used to identify the MNPs. The catalytic activity of the MNPs was evaluated in the one‐pot synthesis of some novel poly‐substituted pyridine derivatives.     

Synthesis of Bis‐Thiazolidinones Using Chitosan‐attached Nano‐CuFe2O4 as an Efficient and Retrievable Heterogeneous Catalyst

The preparation of bis‐thiazolidinones has been achieved by a one‐pot condensation reaction of araldehydes, ethylenediamine, and 2‐mercaptoacetic acid in the presence of nano‐CuFe₂O₄@chitosan under reflux conditions in toluene. The catalyst was characterized by powder X‐ray diffraction (XRD), scanning electronic microscopy (SEM), vibrating sample magnetometer (VSM) measurements, thermal gravimetric analysis (TGA), and FT‐IR spectroscopy. This method provides several advantages including excellent yields, wide range of products, reusability of the catalyst, and a low amount of the catalyst.     

Zn(L‐proline)2 as an efficient and reusable catalyst for the multi‐component synthesis of pyran‐annulated heterocyclic compounds

We have developed a simple, straightforward and highly efficient multi‐component one‐pot synthesis of 2‐amino‐3‐cyano‐4H‐pyrans and pyran‐annulated heterocyclic compounds. Zn(L‐proline)₂ has been utilized as a mild and efficient Lewis acid catalyst for the three‐component reaction of aromatic aldehydes, malononitrile and enolizable C‐H acids or activated phenols to synthesize pyran‐annulated scaffolds. 3‐Methyl‐1‐phenyl‐2‐pyrazolin‐5‐one, 4‐hydroxycoumarine, dimedone, 4‐hydroxy‐6‐methyl‐2‐pyrone, resorcinol, 1‐naphthol and 2‐naphthol were used as activated C‐H acids. The products were isolated in high yields via vacuum filtration and without using any chromatography. The Zn(L‐proline)₂ was recovered and reused in another reaction (three times) without significant loss of activity.     

Synthesis of pyranopyrazoles using nano‐Fe‐[phenylsalicylaldiminemethylpyranopyrazole]Cl2 as a new Schiff base complex and catalyst

By the condensation reaction of benzaldehyde with ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of FeCl₂, a pyranopyrazole derivative was prepared which was then reacted with salicylaldehyde to afford nano‐Fe‐[phenylsalicylaldiminemethylpyranopyrazole]Cl₂ (nano‐[Fe‐PSMP]Cl₂). The prepared nano‐Schiff base complex was fully characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, differential thermogravimetry, scanning electron microscopy and UV–visible spectroscopy, and was used as an efficient and catalyst for the preparation of pyranopyrazoles.     

Fe3O4@TiO2@O2PO2(CH2)NHSO3H as a novel nanomagnetic catalyst: Application to the preparation of 2‐amino‐4,6‐diphenylnicotinonitriles via anomeric‐based oxidation

A new, green and reusable nanomagnetic heterogeneous catalyst, namely Fe₃O₄@TiO₂@O₂PO₂(CH₂)NHSO₃H, was synthesized and fully characterized using suitable techniques such as infrared spectroscopy, X‐ray diffraction, scanning and transmission electron microscopies, thermogravimetry, vibrating sample magnetometry and energy‐dispersive X‐ray spectroscopy. The applicability of the constructed heterogeneous core–shell catalyst as a promoter was successfully explored for the synthesis of 2‐amino‐4,6‐diphenylnicotinonitrile derivatives upon the reaction of a good range of aromatic aldehydes, acetophenone derivatives, malononitrile and ammonium acetate. The desired products were obtained with good to high yields in short reaction times under solvent‐free conditions. The suggested mechanism offers an anomeric‐based oxidation route to the products in the final step of the synthetic pathway.