23309-09-3Relevant academic research and scientific papers
A post-synthetically modified metal-organic framework for copper catalyzed denitrative C-N coupling of nitroarenes under heterogeneous conditions
Maity, Tanmoy,Ghosh, Pameli,Das, Soma,Saha, Debraj,Koner, Subratanath
supporting information, p. 5568 - 5575 (2021/04/06)
Here we report, for the first time, the Ullmann C-N coupling reaction of nitroarenes which is achieved by using a copper containing metal-organic framework (MOF) catalyst under heterogenous conditions. The ready availability of nitroarenes and their low cost have made them ideal replacements for haloarenes as electrophilic coupling partners. Notably, the reaction protocol suppresses the by-product formation in the catalytic reaction. The catalyst has been designed and synthesized by two step post-synthesis functionalization of a MOF,viz.dabco MOF-1 with a -NH2functional group (DMOF-NH2). In the post-synthetic treatment, salicylaldehyde has been used for organic modification first and then copper(ii) was successfully incorporated onto the inner surface of the porous material. The hybrid porous solid thus obtained has been employed in the catalytic C-N coupling reaction of nitroarenes with a wide variety of amines under heterogeneous conditions, which displayed very high turnover frequencies (TOF) in catalytic reactions attesting its efficacy towards theN-arylation reaction.
Cu(OAc)2-porphyrins as an efficient catalytic system for base-free, nature mimicking Chan–Lam coupling in water
Venkateswarlu, Katta,Rao, Kanusu Umamaheswara
, (2021/03/03)
The use of porphyrins as ligands in organic synthesis reveals the natural process, because these are the constituent motifs of catalysts in many bio-organic reactions. This article presents the synthesis of two N-pincer tetradentate porphyrins; tetrasodium meso-tetra(p-sulfonatophenyl)phorphyrin (H2TSTpSPP) and meso-tetra(m-carboxyphenyl)porphyrin (H2TmCPP), and study on their aptness for Cu-catalyzed C–N coupling reactions of arylboronic acids and amines (Chan–Lam coupling reaction) in water under external base free conditions. The porphyrins and Chan–Lam coupling products were well characterized by their spectral analysis. The high product yields, application of nature-inspired conditions, large extent of substrates, ease of making and handling the ligands, avoidance of base, and use of water as reaction media are the attractive attributes of this finding.
Immobilization of copper(II) into polyacrylonitrile fiber toward efficient and recyclable catalyst in Chan-Lam coupling reactions
Zhang, Chenlu,Zhu, Hai,Gang, Kaiyue,Tao, Minli,Ma, Ning,Zhang, Wenqin
, (2021/02/09)
A series of polyacrylonitrile fiber (PANF)-supported copper(II) catalysts were prepared through the immobilization of Cu(II) into prolinamide-modified PANF (PANPA-2F) and subsequently used for the synthesis of diverse N-arylimidazoles from arylboronic acids and imidazole. The prepared Cu(II)@PANPA-2Fs were well characterized by mechanical strength, FT-IR, XRD, XPS and SEM. Among them, CuCl2@PANPA-2F exhibited excellent catalytic performance, and its activity was significantly affected by the Cu loading. This catalytic system also displayed good activity in the synthesis of N-arylsulfonamides from arylboronic acids and tosyl azide. It was highly efficient in gram-scale reactions and could be reused five times. The advantages of low cost, easy preparation, good durability and facile recovery make the fiber catalyst attractive.
Facile synthesis of hydrochar supported copper nanocatalyst for Ullmann C–N coupling reaction in water
Ge, Xin,Ge, Meng,Chen, Xinzhi,Qian, Chao,Liu, Xuemin,Zhou, Shaodong
, (2019/12/24)
The exploration of inexpensive and stable heterogeneous catalysts and application of green solvents for Ullmann C–N coupling reaction remain challenging. We present a facile fabrication of copper nanoparticles on hydrochar as prepared from natural, inexpensive and renewable chitosan together with in-situ reduction of copper salt in a one-pot hydrothermal carbonization process. The copper nanoparticles were uniformly dispersed on hydrochar by choosing block copolymer F127 as surfactant. Moreover, maleic acid was introduced to improve the hydrophilicity of hydrochar. The most active copper nanocomposite catalyst, that is, Cu/HCS-MA-F127, exhibited excellent catalytic activity for Ullmann C–N coupling reaction in water. The nature of the Cu/HCS-MA-F127 was characterized by FTIR spectroscopy, TG, XRD, SEM and XPS. Moderate to excellent yields of aimed products were gained by using this catalytic strategy. Moreover, the Cu/HCS-MA-F127 catalyst can be reused by simple centrifugal recovery with a stable performance.
Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
supporting information, (2019/05/01)
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
supporting information, p. 3924 - 3939 (2019/05/06)
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles as a novel recyclable catalyst for N-arylation of nitrogen heterocycles and green synthesis of 5-substituted 1H-tetrazoles
Esmaeilpour, Mohsen,Sardarian, Ali Reza,Firouzabadi, Habib
, (2018/03/21)
In this study, dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles were prepared via a multistep-synthesis. Then, the synthesized composite was fully characterized by various techniques such as fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), UV-vis spectroscopy, energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA) and vibration sample magnetometer (VSM). From the information gained by. FE-SEM and TEM studies it can be inferred that the particles are mostly spherical in shape and have an average size of 50?nm. Also, the amount of Cu is determined to be 0.51?mmol/g in the catalyst by inductively coupled plasma (ICP) analyzer. This magnetic nano-compound has been successfully applied as a highly efficient, magnetically recoverable and stable catalyst for N-arylation of nitrogen heterocycles with aryl halides (I, Br) and arylboronic acids without using external ligands or additives. The catalyst was also employed in a one-pot, three-component reaction for the efficient and green synthesis of 5-substituted 1H-tetrazoles using various aldehydes, hydroxylamine hydrochloride and sodium azide in water. The magnetic catalyst can be easily separated by an external magnet bar and is recycled seven times without significant loss of its activity.
Cu-doped CoFe2O4 nanoparticles as magnetically recoverable catalyst for C–N cross-coupling reaction
Dutta, Mintu Maan,Phukan, Prodeep
, p. 38 - 42 (2018/03/01)
A new hybrid catalyst has been developed by immobilizing copper acetate onto surface of cobalt ferrite magnetic nanoparticles bearing N–O chelating ligand. The magnetic core of the catalyst was synthesized via ultrasound assisted co-precipitation method and characterized by FT-IR, XRD, EDX, SEM, TEM, TGA and VSM analysis. The catalyst was found to be very active for C–N bond forming reaction. Coupling of amines and aryl boronic acid could be achieved in high yield in methanol in presence of triethylamine at room temperature. After completion of the reaction the catalyst could be recovered using an external magnet and reused for consecutive catalytic cycles without significant decrease in the catalytic activity.
Salen complex of Cu(II) supported on superparamagnetic Fe3O4@SiO2 nanoparticles: an efficient and magnetically recoverable catalyst for N-arylation of imidazole with aryl halides
Sardarian, Ali Reza,Zohourian-Mashmoul, Neda,Esmaeilpour, Mohsen
, p. 1101 - 1109 (2018/02/21)
Abstract: The Fe3O4@SiO2/Salen-Cu(II) nanocatalyst is reported as a thermally and air-stable, economical, and magnetically recoverable heterogeneous catalyst for the selective and efficient N-(hetero)arylation of imidazole. Only by adding a small amount of the catalyst (0.4?mol% Cu) to the reactants and heating under air, the new presented method provides a variety of functionalized and hindered N-(hetero)arylimidazoles in good to excellent yields within short reaction times. The catalyst could be easily recovered with the aid of a permanent magnet and reused up to five consecutive runs without significant loss of activity. Also, the leaching of Cu was negligible after the fifth recycle. Particularly, using either (hetero)aryl iodides or bromides as arylating agents and the need of only small amount of the magnetically recoverable heterogeneous copper-based nanocatalyst make this method low-cost, environmentally benign, and easy to use. Graphical abstract: [Figure not available: see fulltext.].
A waste-minimized protocol for copper-catalyzed Ullmann-type reaction in a biomass derived furfuryl alcohol/water azeotrope
Ferlin, Francesco,Trombettoni, Valeria,Luciani, Lorenzo,Fusi, Soliver,Piermatti, Oriana,Santoro, Stefano,Vaccaro, Luigi
supporting information, p. 1634 - 1639 (2018/04/12)
We report the use of biomass-derived furfuryl alcohol as an effective bidentate ligand able to promote the Ullmann-type copper-catalyzed coupling of aryl halides with heteroaromatic or aliphatic amines. Furfuryl alcohol (FA) can be mixed with water to form the corresponding azeotrope (20 wt% of FA) and therefore can be easily recovered and reused. This protocol is efficiently applied to substrates with various electronic nature and affords the expected products (27 examples) in generally good to excellent yields. It has also been demonstrated that the protocol is both chemically and environmentally effective as the azeotropic mixture can be easily and almost quantitatively recovered at the end of the process.
