32804-22-1Relevant academic research and scientific papers
Electrochemical Reductive Arylation of Nitroarenes with Arylboronic Acids
Wang, Dan,Wan, Zhaohua,Zhang, Heng,Alhumade, Hesham,Yi, Hong,Lei, Aiwen
, p. 5399 - 5404 (2021/10/20)
The synthesis of diarylamine is extremely important in organic chemistry. Herein, a novel electrochemical reductive arylation of nitroarenes with arylboronic acids was developed. A variety of diarylamines were synthesized without the need for transition-metal catalysts. The reaction could be scaled up efficiently in a flow cell and several derivatization reactions were carried out smoothly. Cyclic voltammetry experiments and mechanism studies showed that acetonitrile, formic acid, and triethyl phosphite all played a role in promoting this reductive arylation transformation.
Cu-ACP-Am-Fe3O4@SiO2: an efficient and recyclable heterogeneous catalyst for the Chan–Lam coupling reaction of boronic acids and amines
Vibhute, Sandip P.,Mhaldar, Pradeep M.,Gaikwad, Dipak S.,Shejwal, Rajendra V.,Pore, Dattaprasad M.
, p. 87 - 92 (2020/01/03)
Abstract: We have developed an efficient method for Cu-ACP-Am-Fe3O4@SiO2 catalyzed Chan–Lam coupling of phenylboronic acid with primary amine furnished secondary amines. The catalyst offered virtues like mild reaction conditions, magnetically separable, and reusable and exhibits excellent performance in terms of good product yield and high turnover number. Graphic abstract: [Figure not available: see fulltext.]
Copper-catalyzed, ceric ammonium nitrate mediated N-arylation of amines
Gonela, Uma Maheshwar,Ablordeppey, Seth Y.
supporting information, p. 2861 - 2864 (2019/02/17)
Cu-Catalyzed, ligand- and base-free cross-coupling of aryl boronic acids with primary and secondary amines has been reported. This ‘Chan-Evans-Lam' reaction has revealed that at room temperature, with a catalytic amount of copper(ii) acetate and ceric ammonium nitrate (CAN) as an oxidant, N-arylation can result in an effective C-N bond formation. This air stable, practical, robust protocol enables tolerance towards a variety of functional groups on both boronic acid and amine partners.
Dearomatization-based novel 1,4 addition type Ugi reaction
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Paragraph 0059-0063, (2019/07/04)
The invention relates to a dearomatization-based novel 1,4 addition type Ugi reaction. The reaction includes steps: taking a 15ml pressure-resistant reaction tube, adding 2mL of trifluoroethanol, sequentially adding imine, acid and t-butylisonitrile into
Copper immobilized at a covalent organic framework: An efficient and recyclable heterogeneous catalyst for the Chan-Lam coupling reaction of aryl boronic acids and amines
Han, Yi,Zhang, Mo,Zhang, Ya-Qing,Zhang, Zhan-Hui
, p. 4891 - 4900 (2018/11/21)
A polyimide covalent organic framework (PI-COF) with high thermal and chemical stabilities has been readily prepared from commercially available and inexpensive reagents and was employed as an effective support for heterogeneous copper. It was demonstrated that the obtained Cu@PI-COF is a highly active heterogeneous catalyst which can effectively promote the Chan-Lam coupling reaction of aryl boronic acids and amines in an open flask without the aid of any base or additive. In addition, the catalyst could be readily recovered from the reaction mixture by simple filtration and reused for at least eight cycles without any observable change in structure and catalytic activity.
Copper Oxide Nanoparticles as a Mild and Efficient Catalyst for N-Arylation of Imidazole and Aniline with Boronic Acids at Room Temperature
Borah, Raju Kumar,Raul, Prasanta Kumar,Mahanta, Abhijit,Shchukarev, Andrey,Mikkola, Jyri-Pekka,Thakur, Ashim Jyoti
, p. 1177 - 1182 (2017/06/13)
The present work describes the excellent catalytic activity of copper(II) oxide nanoparticles (NPs) towards N-arylation of aniline and imidazole at room temperature. The copper(II)oxide NPs were synthesized by a thermal refluxing technique and characterized by FT-IR spectroscopy; powder XRD, SEM, EDX, TEM, TGA, XPS, BET surface area analysis, and particle size analysis. The size of the NPs was found to be around 12 nm having a surface area of 164.180 m 2 g -1.The catalytic system was also found to be recyclable and could be reused in subsequent catalytic runs without a significant loss of activity.
Versatile routes for synthesis of diarylamines through acceptorless dehydrogenative aromatization catalysis over supported gold-palladium bimetallic nanoparticles
Taniguchi, Kento,Jin, Xiongjie,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
, p. 2131 - 2142 (2017/03/09)
Diarylamines are an important class of widely utilized chemicals, and development of diverse procedures for their synthesis is of great importance. Herein, we have successfully developed novel versatile catalytic procedures for the synthesis of diarylamines through acceptorless dehydrogenative aromatization. In the presence of a gold-palladium alloy nanoparticle catalyst (Au-Pd/TiO2), various symmetrically substituted diarylamines could be synthesized starting from cyclohexylamines. The observed catalysis of Au-Pd/TiO2 was heterogeneous in nature and Au-Pd/TiO2 could be reused several times without severe loss of catalytic performance. This transformation needs no oxidants and generates molecular hydrogen (three equivalents with respect to cyclohexylamines) and ammonia as the side products. These features highlight the environmentally benign nature of the present transformation. Furthermore, in the presence of Au-Pd/TiO2, various kinds of structurally diverse unsymmetrically substituted diarylamines could successfully be synthesized starting from various combinations of substrates such as (i) anilines and cyclohexanones, (ii) cyclohexylamines and cyclohexanones, and (iii) nitrobenzenes and cyclohexanols. The role of the catalyst and the reaction pathways were investigated in detail for the transformation of cyclohexylamines. The catalytic performance was strongly influenced by the nature of the catalyst. In the presence of a supported gold nanoparticle catalyst (Au/TiO2), the desired diarylamines were hardly produced. Although a supported palladium nanoparticle catalyst (Pd/TiO2) gave the desired diarylamines, the catalytic activity was inferior to that of Au-Pd/TiO2. Moreover, the activity of Au-Pd/TiO2 was superior to that of a physical mixture of Au/TiO2 and Pd/TiO2. The present Au-Pd/TiO2-catalyzed transformation of cyclohexylamines proceeds through complex pathways comprising amine dehydrogenation, imine disproportionation, and condensation reactions. The amine dehydrogenation and imine disproportionation reactions are effectively promoted by palladium (not by gold), and the intrinsic catalytic performance of palladium is significantly improved by alloying with gold. One possible explanation of the alloying effect is the formation of electron-poor palladium species that can effectively promote the β-H elimination step in the rate-limiting amine dehydrogenation.
C–N cross-coupling on supported copper catalysts: The effect of the support, oxidation state, base and solvent
Tirsoaga, Alina,Cojocaru, Bogdan,Teodorescu, Cristian,Vasiliu, Florin,Grecu, Maria Nicoleta,Ghica, Daniela,Parvulescu, Vasile I.,Garcia, Hermenegildo
, p. 205 - 220 (2016/08/04)
A series of supported copper catalysts at two different loadings (1 and 2?wt%) have been prepared by deposition precipitation on various supports including TiO2, ZnO, Al2O3 and active carbon and submitted or not to reductive treatments to favor the increase in population of Cu(I). The samples have been characterized by textural measurements, electron microscopy and spectroscopic techniques including EPR and XPS, concluding the presence of dispersed copper oxides on the support with small particle size and contrasting prevalence of Cu(II) or Cu(I). The catalytic activity of all these catalysts for the C–N coupling of aniline and bromobenzene has been evaluated. A strong influence of the support, copper oxidation state, solvent, nature of the base was observed, the optimal conditions being the use of ZnO or TiO2 as supports and toluene/dioxane as solvent and EtOK as base. t-C5H11OK as base in either THF or toluene give rise to the formation of t-C5H11 phenyl ether in some extent. The catalyst undergoes deactivation during the reaction, but about 88% of the activity of the fresh sample could be regained by dioxane washings before reuse. XPS indicates that the most likely origin of catalyst deactivation is adsorption on the copper catalyst surface of KBr and inorganic salts formed as byproducts during the reaction.
Facile access to: N -substituted anilines via dehydrogenative aromatization catalysis over supported gold-palladium bimetallic nanoparticles
Taniguchi, Kento,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 3929 - 3937 (2016/06/14)
N-Substituted anilines are widely utilized important compounds, and the development of their diverse synthetic procedures is of great significance. Herein, we have successfully developed a widely applicable powerful catalytic route to N-substituted anilines. In the presence of a gold-palladium alloy nanoparticle catalyst (Au-Pd/Al2O3) and styrene, various kinds of structurally diverse N-substituted anilines (twenty three examples) could be synthesized starting from cyclohexanones and amines (including aliphatic primary and secondary amines and anilines). The catalytic performance was strongly influenced by the nature of the catalyst. A supported gold catalyst (Au/Al2O3) was completely inactive for the present transformation. Although a supported palladium catalyst (Pd/Al2O3) gave the desired N-substituted anilines to some extent, the performance was inferior to that of Au-Pd/Al2O3. The catalytic activity of the palladium species in Au-Pd/Al2O3 was at least ca. three times higher than that in Pd/Al2O3. Moreover, the performance of Au-Pd/Al2O3 was superior to that of a physical mixture of Au/Al2O3 and Pd/Al2O3. Thus, palladium was intrinsically effective for the present transformation (dehydrogenative aromatization) and its performance was improved by alloying with gold. The present transformation proceeds through a sequence of the dehydrative condensation of cyclohexanones and amines to produce enamines (or ketimines), followed by the dehydrogenative aromatization to produce the corresponding N-substituted anilines. In the aromatization step, styrene could act as an effective hydrogen acceptor to selectively produce the desired N-substituted anilines without catalyzing the disproportionation of the enamine intermediates. The observed catalysis using Au-Pd/Al2O3 was truly heterogeneous in nature, and Au-Pd/Al2O3 could be reused.
A catalyst system, copper/ N -methoxy-1 H -pyrrole-2-carboxamide, for the synthesis of phenothiazines in poly(ethylene glycol)
Huang, Manna,Hou, Jianying,Yang, Ruiqiao,Zhang, Liting,Zhu, Xinhai,Wan, Yiqian
, p. 3356 - 3364 (2015/02/02)
A copper/N-methoxy-1H-pyrrole-2-carboxamide catalyst system has been established for the preparation of phenothiazines in good yields by two routes, starting from 2-iodoanilines and 2-bromobenzenethiol and from aryl ortho-dihalides and o-aminobenzenethiols, by conducting the reaction at 90 °C in poly(ethylene glycol)-100 (PEG-100). In addition, the catalyst system was useful for promoting direct arylation of various aryl amines, aliphatic amines, and aqueous ammonia. The simple experimental operation, low loading of catalyst system together with the use of green solvent, makes it attractive for the versatile syntheses of phenothiazines and various amines.
