4058-18-8Relevant academic research and scientific papers
Reductive C?N Coupling of Nitroarenes: Heterogenization of MoO3 Catalyst by Confinement in Silica
Yang, Fu,Dong, Xuexue,Shen, Yang,Liu, Mengting,Zhou, Hu,Wang, Xuyu,Li, Lulu,Yuan, Aihua,Song, Heng
, p. 3413 - 3421 (2021/07/31)
The construction of C?N bonds with nitroaromatics and boronic acids using highly efficient and recyclable catalysts remains a challenge. In this study, nanoporous MoO3 confined in silica serves as an efficient heterogeneous catalyst for C?N cross-coupling of nitroaromatics with aryl or alkyl boronic acids to deliver N-arylamines and with desirable multiple reusability. Experimental results suggest that silica not only heterogenizes the Mo species in the confined mesoporous microenvironment but also significantly reduces the reaction induction period and regulates the chemical efficiency of the targeted product. The well-shaped MoO3@m?SiO2 catalyst exhibits improved catalytic performance both in yield and turnover number, in contrast with homogeneous Mo catalysts, commercial Pd/C, or MoO3 nanoparticles. This approach offers a new avenue for the heterogeneous catalytic synthesis of valuable bioactive molecules.
Mediator-Enabled Electrocatalysis with Ligandless Copper for Anaerobic Chan-Lam Coupling Reactions
Walker, Benjamin R.,Manabe, Shuhei,Brusoe, Andrew T.,Sevov, Christo S.
supporting information, p. 6257 - 6265 (2021/05/07)
Simple copper salts serve as catalysts to effect C-X bond-forming reactions in some of the most utilized transformations in synthesis, including the oxidative coupling of aryl boronic acids and amines. However, these Chan-Lam coupling reactions have historically relied on chemical oxidants that limit their applicability beyond small-scale synthesis. Despite the success of replacing strong chemical oxidants with electrochemistry for a variety of metal-catalyzed processes, electrooxidative reactions with ligandless copper catalysts are plagued by slow electron-transfer kinetics, irreversible copper plating, and competitive substrate oxidation. Herein, we report the implementation of substoichiometric quantities of redox mediators to address limitations to Cu-catalyzed electrosynthesis. Mechanistic studies reveal that mediators serve multiple roles by (i) rapidly oxidizing low-valent Cu intermediates, (ii) stripping Cu metal from the cathode to regenerate the catalyst and reveal the active Pt surface for proton reduction, and (iii) providing anodic overcharge protection to prevent substrate oxidation. This strategy is applied to Chan-Lam coupling of aryl-, heteroaryl-, and alkylamines with arylboronic acids in the absence of chemical oxidants. Couplings under these electrochemical conditions occur with higher yields and shorter reaction times than conventional reactions in air and provide complementary substrate reactivity.
Design, preparation and characterization of aerogel NiO-CuO-CoO/SiO2 nanocomposite as a reusable catalyst for C-N cross-coupling reaction
Ghasemi, Amir Hossein,Naeimi, Hossein
supporting information, p. 5056 - 5063 (2020/04/09)
Aerogels are porous, non-crystalline solid materials with high specific surface space, plentiful three-dimensional (3D) porous construction, ultra-low density and significant porosity. The aerogel nanocomposite is produced using sol-gel and supercritical drying processes. CO2 supercritical drying (SCD) is the most powerful process, ensuring optimal product properties such as high porosity, low density, and high thermal conductivity. On this account, we used the CO2 supercritical drying method to produce NiO-CuO-CoO/SiO2 nanocomposite aerogels and applied it as a reusable catalyst for the C-N cross-coupling reaction (Buchwald-Hartwig amination). Powerful catalytic activity for the C-N cross-coupling reaction was obtained for the new nanocomposite aerogel, that is, NiO-CuO-CoO/SiO2. The catalyst was characterized by X-ray Powder Diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping and Brunauer-Emmett-Teller (BET). Also, organic compounds were identified by melting point, Fourier-transform infrared spectroscopy (FT-IR) and hydrogen-1 nuclear magnetic resonance (1H NMR) analyses.
Ullmann-type: N-arylation of anilines with alkyl(aryl)sulfonium salts
Tian, Ze-Yu,Zhang, Cheng-Pan
supporting information, p. 11936 - 11939 (2019/10/11)
A palladium/copper-cocatalyzed Ullmann-type N-arylation of anilines using alkyl(aryl)sulfonium triflates as arylation reagents has been accomplished. The reaction enabled Caryl-S bond cleavage over Calkyl-S bond breakage of alkyl(aryl)sulfoniums by Pd(P(tBu)3)2/CuI and gave the corresponding N-arylated products in good to high yields. It was also significant that the reactions of aniline with asymmetric butyl(mesityl)(aryl)sulfonium triflates showed excellent selectivity, in which the aryl groups other than the bulky and electron-rich mesityl moieties were transformed.
Reductive Molybdenum-Catalyzed Direct Amination of Boronic Acids with Nitro Compounds
Suárez-Pantiga, Samuel,Hernández-Ruiz, Raquel,Virumbrales, Cintia,Pedrosa, María R.,Sanz, Roberto
supporting information, p. 2129 - 2133 (2019/01/25)
The synthesis of aromatic amines is of utmost importance in a wide range of chemical contexts. We report a direct amination of boronic acids with nitro compounds to yield (hetero)aryl amines. The novel combination of a dioxomolybdenum(VI) catalyst and triphenylphosphine as inexpensive reductant has revealed to be decisive to achieve this new C?N coupling. Our methodology has proven to be scalable, air and moisture tolerant, highly chemoselective and engages both aliphatic and aromatic nitro compounds. Moreover, this general and step-economical synthesis of aromatic secondary amines showcases orthogonality to other aromatic amine syntheses as it tolerates aryl halides and carbonyl compounds.
Electrochemically Enabled Chan-Lam Couplings of Aryl Boronic Acids and Anilines
Wexler, Ryan P.,Nuhant, Philippe,Senter, Timothy J.,Gale-Day, Zachary J.
supporting information, p. 4540 - 4543 (2019/06/27)
The Chan-Lam reaction remains a highly utilized transformation for C-N bond formation. However, anilines remain problematic substrates due to their lower nucleophilicity. To address this problem, we developed an electrochemically mediated Chan-Lam coupling of aryl boronic acids and amines utilizing a dual copper anode/cathode system. The mild conditions identified have enabled the preparation of a wide range of functionalized biarylanilines in good yields and chemoselectivities.
Discovery of carbazole carboxamides as novel RORγt inverse agonists
Huang, Yafei,Yu, Mingcheng,Sun, Nannan,Tang, Ting,Yu, Fazhi,Song, Xiaoxia,Xie, Qiong,Fu, Wei,Shao, Liming,Wang, Yonghui
, p. 465 - 476 (2018/02/28)
A novel series of carbazole carboxamides was discovered as potent RORγt inverse agonists using a scaffold hybridization strategy. Structure-activity relationship exploration on the amide linker, carbazole ring and arylsulfone moiety of the hybrid amide 3a led to identification of potent RORγt inverse agonists. Compound 6c was found to have a good RORγt activity with an IC50 of 58.5 nM in FRET assay, and reasonable inhibitory activity in mouse Th17 cell differentiation assay (58.8% inhibition at 0.3 μM). The binding mode of carbazole carboxamides in RORγt ligand binding domain was discussed.
Spectroscopic Studies of the Chan-Lam Amination: A Mechanism-Inspired Solution to Boronic Ester Reactivity
Vantourout, Julien C.,Miras, Haralampos N.,Isidro-Llobet, Albert,Sproules, Stephen,Watson, Allan J. B.
supporting information, p. 4769 - 4779 (2017/04/11)
We report an investigation of the Chan-Lam amination reaction. A combination of spectroscopy, computational modeling, and crystallography has identified the structures of key intermediates and allowed a complete mechanistic description to be presented, including off-cycle inhibitory processes, the source of amine and organoboron reactivity issues, and the origin of competing oxidation/protodeboronation side reactions. Identification of key mechanistic events has allowed the development of a simple solution to these issues: manipulating Cu(I) → Cu(II) oxidation and exploiting three synergistic roles of boric acid has allowed the development of a general catalytic Chan-Lam amination, overcoming long-standing and unsolved amine and organoboron limitations of this valuable transformation.
A method for preparing aromatic amine derivative
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Paragraph 0161-0164, (2016/10/08)
The invention discloses a preparation method of a diarylamine ramification. The preparation method comprises the following steps: dissolving a phenylamine ramification, a phenylhydrazine ramification, a metal phthalocyanine ramification and a copper salt into a solvent, and reacting at -10 to 40 DEG C to obtain the diarylamine ramification. According to the preparation method, the phenylamine ramification and the phenylhydrazine ramification are taken as starting materials, so that raw materials are easy to obtain and plenty in variety; a product obtained by utilizing the method is plenty in type, can not only be directly used, but also be used for other further reactions; and no additive is required to be added. The preparation method disclosed by the invention has the advantages of short synthetic route, moderation in reaction condition, simple reaction operation and post-processing process, high yield and suitability for large-scale production.
