- Support effect of Rh catalysts on the hydrogenation of m-dinitrobenzene
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The effect of the support (ZrO2, Al2O3, and TiO2) of Rh (1 wt%) catalysts for the hydrogenation of m-dinitrobenzene (m-DNB) in liquid phase was studied. The catalysts were reduced at 300 °C and characterized by
- Martínez, José J.,Aguilera, Edna X.,Cubillos, Jairo,Rojas, Hugo,Gómez-Cortés, Antonio,Díaz, Gabriela
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- Mesoporous nickel-aluminum mixed oxide: A promising catalyst in hydride-transfer reactions
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The design and synthesis of a new nanostructured material that can efficiently catalyze selective reduction reactions in an eco-friendly way is an active area of research today. Here a mesoporous Ni-Al mixed oxide material has been synthesized hydrotherma
- Paul, Manidipa,Pal, Nabanita,Bhaumik, Asim
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- Carbon supported gold and silver: Application in the gas phase hydrogenation of m-dinitrobenzene
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Abstract We have studied the gas phase continuous hydrogenation of m-dinitrobenzene (m-DNB) over acid treated activated carbon (AC) supported Au and Ag prepared by deposition-precipitation. Temperature programmed reduction of a 1%wt. metal loading generat
- Cárdenas-Lizana, Fernando,De Pedro, Zahara M.,Gómez-Quero, Santiago,Kiwi-Minsker, Lioubov,Keane, Mark A.
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- A PET-based fluorescent probe for monitoring labile Fe(ii) pools in macrophage activations and ferroptosis
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A fluorescent probe (COU-LIP-1) for monitoring labile Fe(ii) pools (LIP) with high selectivity and sensitivity was developed utilizing coumarin 343 as the fluorophore and 3-nitrophenylazanyl ester as both the reactive group and the fluorescence quenching group. Fe(ii)-induced reductive cleavage of the N-O bond results in a turn-on response via a photo-induced photon transfer (PET) mechanism. The probe was applied for monitoring labile iron(ii) changes in M1 and M2a macrophage activations and also erastin-induced ferroptosis, providing a powerful tool for selectively sensing LIP under both physiological and stressed conditions.
- Abedi, Syed Ali Abbas,Liu, Xiaogang,Lou, Kaiyan,Ma, Huijuan,Wang, Shanshan,Wang, Wei,Xing, Wanjin,Xu, Hang,Xu, Huan,Zhang, Xingchen
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supporting information
p. 2979 - 2982
(2022/03/15)
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- Au/Ni/Ni(OH)2/C Nanocatalyst with High Catalytic Activity and Selectivity for m-dinitrobenzene Hydrogenation
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The Au/Ni/Ni(OH)2/C bimetallic nanocatalysts with different Au loadings (Au/Ni/Ni(OH)2/C-1: 0.05 wt%Au; Au/Ni/Ni(OH)2/C-2: 0.46 wt%Au; Au/Ni/Ni(OH)2/C-3: 2.60 wt%Au) were prepared at room temperature. The characterization results proved the nanostructure of Au islands supported on the Ni/Ni(OH)2 nanoparticles (NPs) and synergy effect of Au-, Ni- and Ni(OH)2-related species in Au/Ni/Ni(OH)2/C. These are the main reasons why their catalytic performance and selectivity to m-nitroaniline in m-dinitrobenzene hydrogenation were much higher than those of monometallic catalysts (Au/C and Ni/Ni(OH)2/C). Because Au/Ni/Ni(OH)2/C-2 was with high dispersion of Au, Au(0)/Aun+ ratio≈1:1 on the surface, novel nanostructure, moderate capacity of activating and dissociating hydrogen, and synergistic effect, it had much better catalytic activity (conversion of m-dinitrobenzene-100%) and higher selectivity to m-nitroaniline (95.0%) in m-dinitrobenzene hydrogenation reaction compared to other two supported bimetallic catalysts (Au/Ni/Ni(OH)2/C-1 and Au/Ni/Ni(OH)2/C-3). Au/Ni/Ni(OH)2/C-2 also exhibited high stability. Graphic abstract: [Figure not available: see fulltext.]
- Ruan, Luna,Fu, Huan,Liao, Jianhua,Ding, Nengwen,Lan, Junjie,Yang, Kai,Rong, Mengke,Zhao, Ning,Zhu, Lihua,Chen, Bing Hui
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- Yeast supported gold nanoparticles: an efficient catalyst for the synthesis of commercially important aryl amines
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Candida parapsilosisATCC 7330 supported gold nanoparticles (CpGNP), prepared by a simple and green method can selectively reduce nitroarenes and substituted nitroarenes with different functional groups like halides (-F, -Cl, -Br), olefins, esters and nitriles using sodium borohydride. The product aryl amines which are useful for the preparation of pharmaceuticals, polymers and agrochemicals were obtained in good yields (up to >95%) using CpGNP catalyst under mild conditions. The catalyst showed high recyclability (≥10 cycles) and is a robust free flowing powder, stored and used after eight months without any loss in catalytic activity.
- Krishnan, Saravanan,Patel, Paresh N.,Balasubramanian, Kalpattu K.,Chadha, Anju
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supporting information
p. 1915 - 1923
(2021/02/06)
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- Aluminum Metal-Organic Framework-Ligated Single-Site Nickel(II)-Hydride for Heterogeneous Chemoselective Catalysis
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The development of chemoselective and heterogeneous earth-abundant metal catalysts is essential for environmentally friendly chemical synthesis. We report a highly efficient, chemoselective, and reusable single-site nickel(II) hydride catalyst based on robust and porous aluminum metal-organic frameworks (MOFs) (DUT-5) for hydrogenation of nitro and nitrile compounds to the corresponding amines and hydrogenolysis of aryl ethers under mild conditions. The nickel-hydride catalyst was prepared by the metalation of aluminum hydroxide secondary building units (SBUs) of DUT-5 having the formula of Al(μ2-OH)(bpdc) (bpdc = 4,4′-biphenyldicarboxylate) with NiBr2 followed by a reaction with NaEt3BH. DUT-5-NiH has a broad substrate scope with excellent functional group tolerance in the hydrogenation of aromatic and aliphatic nitro and nitrile compounds under 1 bar H2 and could be recycled and reused at least 10 times. By changing the reaction conditions of the hydrogenation of nitriles, symmetric or unsymmetric secondary amines were also afforded selectively. The experimental and computational studies suggested reversible nitrile coordination to nickel followed by 1,2-insertion of coordinated nitrile into the nickel-hydride bond occurring in the turnover-limiting step. In addition, DUT-5-NiH is also an active catalyst for chemoselective hydrogenolysis of carbon-oxygen bonds in aryl ethers to afford hydrocarbons under atmospheric hydrogen in the absence of any base, which is important for the generation of fuels from biomass. This work highlights the potential of MOF-based single-site earth-abundant metal catalysts for practical and eco-friendly production of chemical feedstocks and biofuels.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Dwivedi, Ashutosh,Manna, Kuntal
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p. 3943 - 3957
(2021/04/12)
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- Highly efficient N-doped carbon supported FeSx-Fe2O3 catalyst for hydrogenation of nitroarenes via pyrolysis of sulfurized N,Fe-containing MOFs
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Integrating MOFs as precursor, especially for employing N-containing organic linkers, with sulfides is an effective method to prepare the highly efficient N-doped carbon supported metal-based catalysts for hydrogenation of nitroarenes. In this work, a N,Fe-containing metal organic frameworks (MOFs; termed as MIL88-HMTA) with spindle-like structure was prepared via self-assembly method, in which hexamethylenetetramine (HMTA) linker was introduced as N source. Subsequently, N-doped carbon supported FeSx-Fe2O3 catalyst (named FeSx-Fe2O3@CN) was fabricated upon the pyrolysis of sulfurized MIL88-HMTA. Catalytic experiments reveal that the FeSx-Fe2O3@CN delivered excellent performance for hydrogenation of nitroarenes in comparison with those of catalyst without sulfidation process (Fe2O3@CN) and conventional MIL88 derived catalyst (Fe2O3@C). The XRD, TEM, SEM/EDX, Raman, UV, and XPS analyses have revealed that the developed FeSx-Fe2O3@CN catalyst exhibited outstanding catalytic efficiency was ascribed to synergistic effect between FeSx and Fe2O3 species, abundant structural defects, more Fe-Nx species, and strengthened decomposition ability of hydrazine hydrate (N2H4?H2O). Furthermore, the effect of sulfidation ratio (the mass ratio between thioacetamide and MIL88-HMTA) towards preparation of the developed FeSx-Fe2O3@CN on the catalytic activity of hydrogenation reaction was also systematically performed. Notably, the optimized catalyst (denoted as FeSx-Fe2O3@CN-8) exhibited unexpected performance and recyclability for hydrogenation of nitroarenes under mild condition. The pyrolysis of sulfurized N-containing MOFs may present a facile approach for fabricating MOFs-derived N-doped carbon supported catalysts, which provides a potential application in heterogeneous catalytic reactions.
- Li, Xuewei,She, Wei,Wang, Jing,Li, Weizuo,Li, Guangming
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- Novel environment-friendly production process for preparing amine product and H - acid through silane chemical reduction of several nitro compounds
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The invention relates to the field of new materials for fine chemicals, and relates to a reduction reaction of a series of nitro compounds, in particular to m-nitroaniline. Several particular important amine compounds such as m-phenylenediamine, 5 - amino o-cresol, 2 - methyl p-phenylenediamine, 1/2 - naphthylamine, H - acid amine and 2, 4, 6 - trimethyl-M-phenylenediamine are prepared from the corresponding mono-or double-nitro compound precursors with a new environmental protection production process technology of and acids derived from the novel process technology. H.
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Paragraph 0020-0026
(2021/09/08)
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- Magnetically‐recoverable Schiff base complex of Pd(II) immobilized on Fe3O4@SiO2 nanoparticles: an efficient catalyst for the reduction of aromatic nitro compounds to aniline derivatives
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Fe3O4@SiO2/Schiff base/Pd(II) is reported as a magnetically recoverable heterogeneous catalyst for the chemoselective reduction of aromatic nitro compounds to the corresponding amines through catalytic transfer hydrogenation (CTH). In this regard, a small amount of the nanocatalyst (0.52?mol% Pd) and hydrazine hydrate, showing safe characteristics and perfect ability as the hydrogen donor, were added to the nitro substrates. The experiments described the successful reduction of aromatic nitro compounds with good to excellent yields and short reaction times. The catalyst, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in seven consecutive reactions without considerable loss in its activity. Moreover, the leaching of Pd was only 3.6% after the seventh run. Thus, the most striking feature of this method is to use a small amount of the magnetic nanocatalyst along with a cheap and safe hydrogen source to produce the important amine substances selectively, which makes the method economical, cheap, environmentally friendly, and simple. Graphic abstract: [Figure not available: see fulltext.]
- Azadi, Sedigheh,Esmaeilpour, Mohsen,Sardarian, Ali Reza
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p. 809 - 821
(2021/07/20)
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- N,S co-doped hierarchically porous carbon materials for efficient metal-free catalysis
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Metal-free carbon catalysts with excellent catalytic performance have drawn much research attention recently. Herein, polymer-derived N,S co-doped carbon catalysts (PDNSC-X) with a hierarchically porous structure were facilely prepared by a cost-effective and convenient strategy via carbonization of a N- and S atom-containing polymer precursor and were subsequently used as efficient metal-free catalysts. The catalytic activity of the as-fabricated PDNSC-800 was greater than those of other reported heteroatom-doped carbon catalysts in catalytic reduction of various nitroarenes. The high catalytic activity of PDNSC-800 was related to the synergistic effects of a high surface area, a hierarchically porous structure, abundant N- and S-containing active sites, and defect formation. In addition, the close relationship between the N species (especially pyrrolic N) and high selectivity in metal-free catalytic synthesis was investigated in the reduction of nitroarenes and selective oxidation of ethylbenzene. This study may provide a new strategy to fabricate specific heteroatom-doped metal-free carbon catalysts for environmentally friendly efficient organic transformation.
- Hu, Xiwei,Sun, Xun,Song, Qiang,Zhu, Yangyang,Long, Yu,Dong, Zhengping
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p. 742 - 752
(2020/02/21)
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- Copper and L-(?)-quebrachitol catalyzed hydroxylation and amination of aryl halides under air
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L-(?)-Quebrachitol, a natural product obtained from waste water of the rubber industry, was utilized as an efficient ligand for the copper-catalyzed hydroxylation and amination of aryl halides to selectively give phenols and aryl amines in water or 95percent ethanol. In addition, the hydroxylation of 2-chloro-4-hydroxybenzoic acid was validated on a 100-g scale under air.
- Bao, Xuefei,Chen, Guoliang,Dong, Jinhua,Du, Fangyu,Li, Hui,Liang, Xinjie,Wu, Ying,Zhang, Yongsheng
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supporting information
(2020/08/03)
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- Tuning acylthiourea ligands in Ru(II) catalysts for altering the reactivity and chemoselectivity of transfer hydrogenation reactions, and synthesis of 3-isopropoxy-1H-indole through a new synthetic approach
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Ru(II)-p-cymene complexes (1–3) containing picolyl based pseudo-acylthiourea ligands (L1-L3) were synthesized and characterized. The crystallographic study confirmed the molecular structures of all the ligands (L1-L3) and complex 3. The catalytic activity of the complexes was tested mainly towards TH of carbonyl compounds and nitroarenes. The influence of steric and electronic effects of the ligands on the chemoselectivity and reactivity were reported. The catalytic activity was enhanced and chemoselectivity was switched after tuning the ligands in the catalysts, compared to their corresponding unmodified Ru(II)-p-cymene complexes. The catalysis was extended to a broad range of substrates including some challenging systems like furfural, benzoylpyridine, benzoquinone, chromanone, etc. The strategy of tuning the bifunctional ligands in the catalysts for effective and selective catalysis worked nicely. Further, the catalysis was extended to one pot synthesis of 3-isopropoxyindole from 2-nitrocinnamaldehyde, the first synthetic route similar to Baeyer Emmerling indole synthesis. All the catalytic experiments exhibited high conversion and selectivity.
- Sathishkumar, Pushpanathan N.,Prabha, Padinhattath Sachind,Bhuvanesh, Nattamai S.P.,Karvembu, Ramasamy
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- A Common, Facile and Eco-Friendly Method for the Reduction of Nitroarenes, Selective Reduction of Poly-Nitroarenes and Deoxygenation of N-Oxide Containing Heteroarenes Using Elemental Sulfur
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A transition metal-free, environment-friendly and practical protocol was developed either for the reduction of nitroarenes or for the deoxygenation of N-oxide containing heteroarenes. The reaction proceeded with the use of a non-toxic and cheap feedstock as elemental sulfur in aqueous methanol under relatively mild conditions. Green chemistry credentials were widely favorable compared to traditional and industrial protocols with good E-factors and a low production of waste. The strategy allowed the efficient reduction of a large variety of substituted-nitroarenes including various o-nitroanilines as well as selective reduction of various poly-nitroarenes in excellent yields with a broad substrate scope. The protocol was successfully extended to the deoxygenation of some N-oxide containing heteroarenes, like benzofuroxans, phenazine N,N'-dioxides, pyridine N-oxides, 2H-indazole N1-oxides, quinoxaline N1,N4-dioxides and benzo[d]imidazole N1,N3-dioxides. A gram-scale example for the synthesis of luminol, in green conditions, was reported. A solid mechanism of reaction was proposed from experimental evidences.
- Cerecetto, Hugo,Romero, Angel H.
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supporting information
(2020/03/23)
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- Synthesis of water soluble Pd-Piperidoimidazolin-2-ylidene complexes and their catalytic activities in neat water
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Through the strategy of water soluble N-heterocyclic carbene (NHC) ligand, Pd-catalyzed reactions were developed in aqueous media. Therefore, four new piperidoimidazolinium salts (1a-d) consisting of sulfonate (a), esther (b, c) and carboxylic acid (d) functionalities and their water-soluble Pd-NHC complexes (2a-d) were synthesized. The new compounds were characterized by elemental analysis, FTIR, TGA, UV–vis and NMR spectroscopy. The catalytic activities of water soluble Pd-NHC complexes (2a-d) were investigated using the Suzuki-Miyaura (S-M) reaction and the reduction of nitroarenes. We found that the water-soluble polar or ionic groups on piperidoimidazolin-2-ylidine had an effect on the catalytic activity. The water-soluble catalyst can be recycled efficiently and reused six times with only a very slight loss of catalytic activity.
- ?ak?r, Sinem,Türkmen, Hayati
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- CuIBiOI is an efficient novel catalyst in Ullmann-type CN– couplings with wide scope—A rare non-photocatalyic application
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Preparation of a new, mixed-cationic layered CuIBiOI was prepared and its non-photocatalytic catalytic properties were explored. This solid substance had BiOI-like, lamellar and deflected structure resulting from CuI ion incorporation in the Bi2O2 layers. The as-prepared substance was fully characterized by XRD, Raman, far IR, UV–DR, XP spectroscopies, thermal (TG-DTG) and analytical (ICP-MS, SEM-EDX) methods, electron microscopies (SEM, TEM) as well as BET surface area measurements. By performing Ullmann-type CN– coupling reactions between aryl halides and aqueous ammonia, its catalytic capabilities were tested. The effects of solvents, added base and catalyst loading as well as reaction time and reaction temperature were scrutinized, and a green way for the reaction was identified. The recyclability of the catalyst without the loss of activity and its general applicability for a wide range of aryl halides were also demonstrated.
- Djerdj, Igor,Kónya, Zoltán,Kocsis, Marianna,Kukovecz, ákos,Pálinkó, István,Sipos, Pál,Varga, Gábor
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- Aromatic C-H amination in hexafluoroisopropanol
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We report a direct radical aromatic amination reaction that provides unprotected anilines with an improvement in the substrate scope compared to prior art. Hydrogen bonding by the solvent hexafluoroisopropanol to anions of cationic species is responsible for increased reactivity and can rationalize the enhancement in substrate scope. Our findings may have bearings on radical additions to arenes for direct C-H functionalization in general.
- D'Amato, Erica M.,B?rgel, Jonas,Ritter, Tobias
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p. 2424 - 2428
(2019/02/28)
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- Divergent Late-Stage (Hetero)aryl C?H Amination by the Pyridinium Radical Cation
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(Hetero)arylamines constitute some of the most prevalent functional molecules, especially as pharmaceuticals. However, structurally complex aromatics currently cannot be converted into arylamines, so instead, each product isomer must be assembled through a multistep synthesis from simpler building blocks. Herein, we describe a late-stage aryl C?H amination reaction for the synthesis of complex primary arylamines that other reactions cannot access directly. We show and rationalize through a mechanistic analysis the reasons for the wide substrate scope and the constitutional diversity of the reaction, which gives access to molecules that would not have been readily available otherwise.
- Ham, Won Seok,Hillenbrand, Julius,Jacq, Jér?me,Genicot, Christophe,Ritter, Tobias
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supporting information
p. 532 - 536
(2019/01/04)
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- A green and recyclable ligand-free copper (I) catalysis system for amination of halonitrobenzenes in aqueous ammonia solution
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The amination of halonitrobenzenes is an important reaction to produce the corresponding nitroanilines. Direct amination of p-chloronitrobenzene (p-CNB) to p-nitroaniline (p-NAN) with aqueous NH3 solution was investigated over various transition metal salts in the absence of ligand, inorganic base and organic solvent. It was found that CuI is the most effective catalyst with respect to p-CNB conversion, p-NAN selectivity (≈ 100%) and the post-reaction separation and recycling. A high p-NAN yield of 97% could be obtained at 200 °C in 6.5 h with molar ratios of NH3/p-CNB and CuI/p-CNB of 21 and 0.1, respectively. A possible reaction mechanism was proposed, in which NH3 was not only a substrate but also a ligand to coordinate with CuI and formed a water-soluble Cu complex, and then it started the catalytic cycle. The influence of reaction variables such as NH3 concentration, CuI concentration, temperature and time on the p-CNB conversion and the p-NAN selectivity was examined. At room temperature the desired product of p-NAN is insoluble in water but the Cu complex catalyst is water-soluble and so the aqueous phase including the catalyst and NH3 can be easily separated and reused for the subsequent reaction runs. The green and sustainable system is effective for the conversion of diverse halonitrobenzenes to nitroanilines.
- Li, Yan,Shi, Ruhui,Lin, Weiwei,Cheng, Haiyang,Zhang, Chao,Arai, Masahiko,Zhao, Fengyu
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- Visible-light-driven Efficient Photocatalytic Reduction of Organic Azides to Amines over CdS Sheet–rGO Nanocomposite
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CdS sheet–rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.
- Singha, Krishnadipti,Mondal, Aniruddha,Ghosh, Subhash Chandra,Panda, Asit Baran
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p. 255 - 260
(2018/01/15)
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- Copper-mediated reduction of azides under seemingly oxidising conditions: Catalytic and computational studies
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The reduction of aryl azides in the absence of an obvious reducing agent is reported. Careful catalyst design led to the production of anilines in the presence of water and air. The reaction medium (toluene/water) is crucial for the success of the reaction, as DFT calculations support the formation of benzyl alcohol as the oxidation product. A singular catalytic cycle is presented for this transformation based on four key steps: nitrene formation through nitrogen extrusion, formal oxidative addition of water, C(sp3)-H activation of toluene and reductive elimination.
- Zelenay, Benjamin,Besora, Maria,Monasterio, Zaira,Ventura-Espinosa, David,White, Andrew J. P.,Maseras, Feliu,Díez-González, Silvia
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p. 5763 - 5773
(2018/11/24)
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- Silver Nanoparticles Engineered Β-Cyclodextrin/Γ-Fe2O3@ Hydroxyapatite Composite: Efficient, Green and Magnetically Retrievable Nanocatalyst for the Aqueous Reduction of Nitroarenes
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Abstract: Ag nanoparticles incorporated β-cyclodextrin conjugated magnetic hydroxyapatite, γ-Fe2O3@HAp-CD.Ag was conveniently synthesized via the grafting of β-cyclodextrin moieties on the hydroxyapatite surface, followed by reacting of the nanocomposite, γ-Fe2O3, with silver nitrate and then its reduction with sodium borohydride. The cavity of β-cyclodextrin units as host material can stabilize the Ag nanoparticles (particles size: 12–14 nm) effectively and prevent their aggregation and separation from the surface. The nanocomposite obtained appears to have an organized structure, with a magnetic γ-Fe2O3 core surrounded by a layer-structured coating shell. The structure and composition of the nanocomposite were confirmed by FT-IR, FE-SEM, TEM, TGA, XRD, EDS, BET, and VSM. This catalytic system selectively reduces the nitro group even in the presence of other sensitive functional groups in good to excellent yields (85–98%).The organometallic nanocatalyst was easily removed from solution using an external magnet and was successfully examined for five runs, with a slight loss of catalytic activity.
- Azaroon, Maedeh,Kiasat, Ali Reza
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p. 745 - 756
(2017/12/26)
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- Unravelling 2-aminoquinazolin-4(3: H)-one as an organocatalyst for the chemoselective reduction of nitroarenes
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A novel, mild and transition metal-free, 2-aminoquinazolin-4(3H)-one-assisted reduction of nitroarenes employing hydrazine hydrate as reducing agent and potassium carbonate as a base is reported. For the first time, the activation of hydrazine hydrate with an organocatalyst has been explored for reduction reactions. Also for the first time, 2-aminoquinazolin-4(3H)-one and its derivatives have been investigated as hydrogen bonding organocatalysts for the reduction of nitroarenes to anilines. Sensitive functional groups such as sulfonamide, carboxyl, amide and halides were well tolerated in this green methodology with scalability and high chemoselectivity.
- Thakur, Maheshwar S.,Nayal, Onkar S.,Rana, Rohit,Kumar, Manoranjan,Sharma, Sushila,Kumar, Neeraj,Maurya, Sushil K.
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supporting information
p. 1373 - 1378
(2018/02/06)
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- Chemoselective hydrogenation of nitroarenes catalyzed by cellulose-supported Pd NPs
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Cellulose-supported palladium nanoparticles (NPs) were prepared by straightforward deposition of metal NPs on modified cellulose. The catalyst exhibited excellent catalytic activity and selectivity in room-temperature hydrogenation of various nitroarenes to arylamines under atmospheric hydrogen pressure in neat water without any additives. High chemoselectivity was also achieved in the hydrogenation of substituted nitroarenes with multiple reducible groups. The catalyst can be recycled by simple centrifugation and reused for at least 4 times without significant decline of yields.
- Li, Dan-dan,Zhang, Jia-wei,Cai, Chun
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- Biomass Sucrose-Derived Cobalt@Nitrogen-Doped Carbon for Catalytic Transfer Hydrogenation of Nitroarenes with Formic Acid
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Fabrication of non-noble metal-based heterogeneous catalysts by a facile and cost-effective strategy for ecofriendly catalytic transfer hydrogenation (CTH) is of great significance for organic transformations. A cobalt@nitrogen-doped carbon (Co@NC) catalyst was prepared from renewable biomass-derived sucrose, harmless melamine, and earth-abundant Co(AcO)2 as the precursor materials by hydrothermal treatment and carbonization. Co nanoparticles (NPs) were coated with NC shells and uniformly embedded in the NC framework. The as-obtained Co@NC-600 (carbonized at 600 °C) catalyst exhibited excellent catalytic efficiency for CTH of various functionalized nitroarenes with formic acid (FA) as hydrogen donor in aqueous solution. The uniformly incorporated N atoms in the C matrix and the encapsulated Co NPs showed synergistic effects in the CTH reactions. A mechanistic analysis indicated that the protons from FA were activated by Co sites after being captured by N atoms, and then reacted with nitroarenes adsorbed on the surface of the catalysts to generate the corresponding aromatic amines. Moreover, the catalyst showed excellent durability and reusability without obvious decrease in activity even after five reaction cycles. Thus, the study reported herein provides a cost-effective, sustainable strategy for fabrication of biomass-derived non-noble metal-based catalysts for green and efficient catalytic transformations.
- Yuan, Man,Long, Yu,Yang, Jin,Hu, Xiwei,Xu, Dan,Zhu, Yangyang,Dong, Zhengping
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p. 4156 - 4165
(2018/11/01)
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- Glucose promoted facile reduction of azides to amines under aqueous alkaline conditions
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A quick and efficient method for the reduction of azides to amines in water using d-glucose and KOH as green reagents is reported. The protocol is simple, inexpensive, scalable, and can be applied to different aromatic, heteroaromatic and sulphonyl azides. A high level of chemoselectivity is observed for azide reduction in the presence of other reducible functionalities like cyano, nitro, ether, ketone, amide and acid. The reaction gets completed in a short time (5-20 minutes), and furnishes the amines in high yield (85-99%). Unlike conventional hydrogenations, this reduction protocol does not require any metal catalyst, elaborate experimental setup or use of high-pressure equipment.
- Chandna, Nisha,Kaur, Fatehjeet,Kumar, Shobhna,Jain, Nidhi
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supporting information
p. 4268 - 4271
(2017/09/29)
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- Highly chemoselective reduction of azides to amines by Fe(0) nanoparticles in water at room temperature
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A highly chemoselective reduction of aryl, heteroaryl, acyl and sulfonyl azides to the corresponding amines has been achieved by Fe(0) nanoparticles in water at room temperature in the absence of external hydride source. Several readily reducible functionalities including alkene, alkyne, S-S linkage, OTBDMS remain unaffected during reduction.
- Panja, Subir,kundu, Debasish,Ahammed, Sabir,Ranu, Brindaban C.
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supporting information
p. 3457 - 3460
(2017/08/10)
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- Synthesis, structural study, thermal, optical properties and characterization of the new compound [C6H7N2O2]3TeCl5·2Cl
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The new organic-inorganic compound, [C6H7N2O2]3TeCl5·2Cl was synthesized and its structure was determined at room temperature in the triclinic system (P?1) with the following parameters: a?=?10.5330(11)??, b?=?10.6663(11)??, c?=?15.9751(16)?, α?=?82.090(2)°, β?=?71.193(2)°, γ?=?68.284(2)° and Z?=?2. The final cycle of refinement led to R?=?0.057 and Rw?=?0.149. The crystal structure was stabilized by an extensive network of N–H?Cl and non-classical C–H?Cl hydrogen bonds between the cation and the anionic group. Several thermal analysis techniques such as thermogravimetric analysis, differential scanning calorimetric analysis and evolved gas analysis were used. We used isoconversional kinetics methods to determine the kinetics parameters. We observe that the decomposition of [C6H7N2O2]3TeCl5·2Cl entails the formation hydrochloric acid of nitroaniline as volatiles. The infrared spectra were recorded in the 4000–400?cm?1 frequency region. The Raman spectra were recorded in the external region of the anionic sublattice vibration 50–1500?cm?1. The optical band gap was calculated from the UV-Vis absorbance spectra using classical Tauc relation which was found to be 3.12 and 3.67?eV.
- Maraii, Dhaou,Farjas, Jordi,Fontrodona, Xavier,Dammak, Mohamed
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p. 1773 - 1779
(2017/07/27)
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- Gold nanoparticles anchored onto the magnetic poly(ionic-liquid) polymer as robust and recoverable catalyst for reduction of Nitroarenes
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Gold nanoparticles supported on poly ionic-liquid magnetic nanoparticles (MNP@PIL@Au) were synthesized by reduction of HAuCl4 with sodium borohydride. The synthesized catalyst was characterized using by AAS, TEM, FT-IR, EDS, TGA and XRD techniques. The performance of the synthesized catalyst was investigated in the reduction of nitroarenes with NaBH4. The reaction was carried out for various nitroarenes in water and mild conditions with high yields. The catalyst selectivity for the reduction of nitro group in the presences of other functional groups such as halides and alkynes was fairly well. The recycling of the catalyst was done 8 times without any significant loss of its catalytic activity.
- Moghaddam, Firouz Matloubi,Ayati, Seyed Ebrahim,Firouzi, Hamid Reza,Hosseini, Seyed Hassan,Pourjavadi, Ali
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- Magnetically Recoverable Gold Nanorods as a Novel Catalyst for the Facile Reduction of Nitroarenes Under Aqueous Conditions
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Abstract: In this work, cysteine-functionalized Fe3O4@Carbon magnetic nanoparticles were used for the synthesis of gold nanorods. Fe3O4@C nanoparticles were first prepared by synthesis of Fe3O4magnetic nanoparticles (MNPs), and then carbon-coated MNPs (Fe3O4@C) were synthesized by glucose carbonization using a hydrothermal method. Finally, the gold NRs were loaded on the modified surface of Fe3O4@C MNPs. The designed magnetically recoverable gold nanorods, after full characterization by FTIR, SEM, TEM, TGA, VSM, XRD, and ICP-OES, were applied to the reduction of nitroarenes. The Fe3O4@C@Cys–Au nanorods showed higher performance than Fe3O4@C@Cys–Au nanospheres in a selective facile reduction of nitroarenes to the corresponding aminoarenes in aqueous medium at room temperature using NaBH4. Graphical Abstract: [Figure not available: see fulltext.]
- Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rostamnia, Sadegh
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p. 491 - 501
(2017/02/18)
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- Chemoselective Deprotection of Sulfonamides under Acidic Conditions: Scope, Sulfonyl Group Migration, and Synthetic Applications
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Chemoselective acidic hydrolysis of sulfonamides with trifluoromethanesulfonic acid has been evaluated as a deprotection method and further extended to more complex synthetic applications. In contrast to conventional troublesome sulfonamide hydrolysis, a near-stoichiometric amount of acid was found to be sufficient to bring about efficient deprotection of various neutral or electron-deficient N-arylsulfonamides, whereas electron-rich substrates provided sulfonyl group migration products. The deprotection method developed is fully selective for N-arylsulfonamides, and the possibility to discriminate among various different sulfonamides is demonstrated.
- Javorskis, Tomas,Orentas, Edvinas
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p. 13423 - 13439
(2017/12/26)
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- Sonication and Microwave-Assisted Primary Amination of Potassium- Aryltrifluoroborates and Phenylboronic Acids under Metal-Free Conditions
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The transition-metal-free generation of a series of primary arylamines from potassium aryltrifluoroborates and phenylboronic acids- is reported. The method uses a mild, inexpensive source of nitrogen (hydroxylamine-O-sulfonic acid) in cooperation with aqueous sodium hydroxide in acetonitrile. Both a sonication and a microwave-assisted method were developed, which are capable of converting ArBF3K functionalities into primary arylamines (ArNH2) in isolated yields of up to 78% (10 examples for each method). This report represents the first general method for the conversion of aryltrifluoroborates into primary arylamines under mild, transition-metal-free conditions in moderate to very good yields. The method is applicable to a wide array of substrates containing electron-donating, electron-neutral, or electron-withdrawing substituents. Both the sonication and microwave methods were also applied to the generation of anilines from phenylboronic acids in isolated yields of up to 96% (12 examples for each method) that were superior to existing room temperature methods in terms of yield, while also offering much shorter reaction times (15 min vs 16 h). In particular, the microwave method is the first to allow for the conversion of arylboronic acids containing strongly electron-withdrawing substituents into the corresponding anilines in good yields, along with electron-donating- substituents in very good to excellent yields.
- Kuik, Dale,McCubbin, J. Adam,Tranmer, Geoffrey K.
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p. 2555 - 2561
(2017/05/22)
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- A highly efficient heterogeneous copper-catalysed cascade reaction of aryl iodides with acetamidine hydrochloride leading to primary arylamines
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A highly efficient heterogeneous copper-catalysed cascade reaction of aryl iodides with acetamidine hydrochloride was achieved in DMF in the presence of 10 mol% of an MCM-41-immobilised L-proline-copper(I) complex (MCM-41-L-proline-CuI) with Cs2CO3 as base, yielding a variety of primary arylamines in good to excellent yields. The new heterogeneous copper complex can be easily prepared from commercially readily available and inexpensive reagents, recovered by a simple filtration of the reaction solution and used at least seven more times without any decrease in activity.
- Huang, Xue,Xiao, Ruian,You, Chongren,Yan, Tao,Cai, Mingzhong
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p. 315 - 320
(2017/06/19)
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- Continuous-Flow Electrophilic Amination of Arenes and Schmidt Reaction of Carboxylic Acids Utilizing the Superacidic Trimethylsilyl Azide/Triflic Acid Reagent System
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A continuous flow protocol for the direct stoichiometric electrophilic amination of aromatic hydrocarbons and the Schmidt reaction of aromatic carboxylic acids using the superacidic trimethylsilyl azide/triflic acid system is described. Optimization of reagent stoichiometry, solvent, reaction time, and temperature led to an intensified protocol at elevated temperatures that allows the direct amination of arenes to be completed within 3 min at 90 °C. In order to improve the selectivity and scope of this direct amination protocol, aromatic carboxylic acids were additionally chosen as substrates. Selected carboxylic acids could be converted to their corresponding amine counterparts in good to excellent yields (11 examples, 55-83%) via a Schmidt reaction employing similar flow reaction conditions (5 min at 90 °C) and a similar reactor setup as for the amination. The safety issues derived from the explosive, toxic, and volatile hydrazoic acid intermediate, the corrosive nature of triflic acid, and the exothermic quenching were addressed by designing a suitable continuous flow reaction setup for both types of transformations.
- Chen, Yuesu,Gutmann, Bernhard,Kappe, C. Oliver
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p. 9372 - 9380
(2016/10/14)
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- A triazine-phosphite polymeric ligand bearing cage-like P,N-ligation sites: An efficient ligand in the nickel-catalyzed amination of aryl chlorides and phenols
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A novel P,N-ligand was introduced for efficient Ni-catalyzed amination of aryl chlorides. Reaction of cyanuric acid (1,3,5-triazine-2,4,6-triol) and trichlorophosphine (PCl3) resulted in the production of a new porous material (TPPM) containing triazine rings with phosphite moieties in a sheet morphology. Cavities in the prepared compound create sites on the surface of the material with appropriate ligation character to coordinate with metals for catalytic purposes. The nickel-catalyzed amination of aryl chlorides and of phenols in their 2,4,6-triaryloxy-1,3,5-triazine (TAT) protected form were efficiently accomplished in the presence of this easily prepared and reusable P,N-ligand under mild reaction conditions. More importantly, TPPM was reusable for 5 iterations following this protocol without significantly decreasing in its activity.
- Panahi, Farhad,Roozbin, Fatemeh,Rahimi, Sajjad,Moayyed, Mohammadesmaeil,Valaei, Aria,Iranpoor, Nasser
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supporting information
p. 80670 - 80678
(2016/10/12)
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- Recyclable and Selective Nitroarene Hydrogenation Catalysts Based on Carbon-Coated Cobalt Oxide Nanoparticles
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Co/CoO nanoparticles coated with graphene layers (Co/CoO@Carbon) have been developed through direct heating treatment of cobalt oxide precursors incipiently deposited over nanographite materials. Cobalt oxides are partially reduced to active zero-valent metal species and the simultaneous formation of carbon layers over the nanoparticles protects them from oxidation and deactivation. This nanocatalyst performs excellently in chemoselective hydrogenation of some challenging nitroarenes with reducible functionalities to the corresponding anilines. The catalyst is kept in active and selective performance in a ten-run recycling test.
- Chen, Bingfeng,Li, Fengbo,Huang, Zhijun,Yuan, Guoqing
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p. 1132 - 1138
(2016/04/05)
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- Ni-based structured catalyst for selective 3-phase hydrogenation of nitroaromatics
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We report herein on the development of Ni-based catalyst using activated carbon fibres (ACFs) as a structured support and its application for the three‐phase hydrogenation of nitroarenes (T?=?353?K; P?=?10?bar). It was shown that metallic Ni0 n
- Beswick, Oliver,Lamey, Daniel,Muriset, Félicien,LaGrange, Thomas,Oberson, Lo?c,Yoon, Songhak,Sulman, Esther,Dyson, Paul J.,Kiwi-Minsker, Lioubov
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p. 244 - 251
(2016/11/22)
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- Structure and Catalytic Activity of Cr-Doped BaTiO3 Nanocatalysts Synthesized by Conventional Oxalate and Microwave Assisted Hydrothermal Methods
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In the present study synthesis of BaTi1-xCrxO3 nanocatalysts (x = 0.0 ≤ x ≤ 0.05) by conventional oxalate and microwave assisted hydrothermal synthesis methods was carried out to investigate the effect of synthesis methods on the physicochemical and catalytic properties of nanocatalysts. These catalysts were thoroughly characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 physisortion, and total acidity by pyridine adsorption method. Their catalytic performance was evaluated for the reduction of nitrobenzene using hydrazine hydrate as the hydrogen source. Structural parameters refined by Rietveld analysis using XRD powder data indicate that BaTi1-xCrxO3 conventional catalysts were crystallized in the tetragonal BaTiO3 structure with space group P4mm, and microwave catalysts crystallized in pure cubic BaTiO3 structure with space group Pm3μm. TEM analysis of the catalysts reveal spherical morphology of the particles, and these are uniformly dispersed in microwave catalysts whereas agglomeration of the particles was observed in conventional catalysts. Particle size of the microwave catalysts is found to be 20-35 nm compared to conventional catalysts (30-48 nm). XPS studies reveal that Cr is present in the 3+ and 6+ mixed valence state in all the catalysts. Microwave synthesized catalysts showed a 4-10-fold increase in surface area and pore volume compared to conventional catalysts. Acidity of the BaTiO3 catalysts improved with Cr dopant in the catalysts, and this could be due to an increase in the number of Lewis acid sites with an increase in Cr content of all the catalysts. Catalytic reduction of nitrobenzene to aniline studies reveals that BaTiO3 synthesized by microwave is very active and showed 99.3% nitrobenzene conversion with 98.2% aniline yield. The presence of Cr in the catalysts facilitates a faster reduction reaction in all the catalysts, and its effect is particularly notable in conventional synthesized catalysts.
- Srilakshmi, Chilukoti,Saraf, Rohit,Prashanth,Rao, G. Mohan,Shivakumara
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p. 4795 - 4805
(2016/06/09)
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- A simple and efficient: In situ generated ruthenium catalyst for chemoselective transfer hydrogenation of nitroarenes: Kinetic and mechanistic studies and comparison with iridium systems
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The catalytic activities of a series of in situ generated homogeneous ruthenium systems based on commercially available [RuCl2(p-cymene)]2 and various ligands in transfer hydrogenation of nitroarenes to anilines were investigated. Combination of [RuCl2(p-cymene)]2 and tridentate phenanthroline based ligand 2-(6-methoxypyridin-2-yl)-1,10-phenanthroline (phenpy-OMe) exhibited the highest catalytic activity for this reaction using 2-propanol as hydrogen source. This protocol provides a facile route to access aromatic amines under mild conditions in excellent yields. Notably, this system chemoselectively reduced the nitro groups over an array of other reactive functionalities such as ketone, alkene, amide, nitrile, and aryl halide. Operational simplicity, high yields, mild reaction conditions and short reaction times make this an attractive methodology for accessing various functionalized anilines. A series of controlled experiments and careful mechanistic investigation with the possible intermediates suggested that transformation of nitrobenzene to aniline with ruthenium and iridium system proceeded via direct route and condensation route respectively.
- Paul, Bhaskar,Chakrabarti, Kaushik,Shee, Sujan,Maji, Milan,Mishra, Anju,Kundu, Sabuj
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p. 100532 - 100545
(2016/11/09)
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- Photoinduced Reduction of Nitroarenes Using a Transition-Metal-Loaded Silicon Semiconductor under Visible Light Irradiation
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We investigated transition-metal-loaded silicon nanoparticles for the photocatalytic reduction of nitroarene derivatives in the presence of formic acid under visible light irradiation. Formic acid assumes the role of both a hydrogen source and a sacrificial reagent for the introduction of electrons into the generated holes of semiconductors. As such, in the presence of formic acid, photocatalytic reactions smoothly proceed under mild conditions without gaseous hydrogen. In particular, palladium-loaded silicon (Pd/Si) was the most suitable catalyst for the conversion of nitrobenzene to aniline, compared to Pt/Si, Ru/Si, and Pd/C.
- Tsutsumi, Ken,Uchikawa, Fumito,Sakai, Kentaro,Tabata, Kenji
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p. 4394 - 4398
(2016/07/12)
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- The ortho effect on the acidic and alkaline hydrolysis of substituted formanilides
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The kinetics of formanilides hydrolysis were determined under first-order conditions in hydrochloric acid (0.01-8 M, 20-60°C) and in hydroxide solutions (0.01-3 M, 25 and 40°C). Under acidic conditions, second-order specific acid catalytic constants were used to construct Hammett plots. The ortho effect was analyzed using the Fujita-Nishioka method. In alkaline solutions, hydrolysis displayed both first- and second-order dependence in the hydroxide concentration. The specific base catalytic constants were used to construct Hammett plots. Ortho effects were evaluated for the first-order dependence on the hydroxide concentration. Formanilide hydrolyzes in acidic solutions by specific acid catalysis, and the kinetic study results were consistent with the AAC2 mechanism. Ortho substitution led to a decrease in the rates of reaction due to steric inhibition of resonance, retardation due to steric bulk, and through space interactions. The primary hydrolytic pathway in alkaline solutions was consistent with a modified BAC2 mechanism. The Hammett plots for hydrolysis of meta- and para-substituted formanilides in 0.10 M sodium hydroxide solutions did not show substituent effects; however, ortho substitution led to a decrease in rate constants proportional to the steric bulk of the substituent.
- Desai, Salil Dileep,Kirsch, Lee E.
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p. 471 - 488
(2015/06/30)
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- Preparation, surface and crystal structure, band energetics, optoelectronic, and photocatalytic properties of AuxCd1-xS nanorods
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A series of novel AuxCd1-xS materials (x=0, 0.01, 0.02, 0.03, 0.05, 0.07, 0.1) were prepared and their optical properties, structural-surface morphology, and photocatalytic activity for oxidation and reduction reactions under visible-light irradiation were studied. X-ray diffraction confirmed the shrinkage of the hexagonal crystal structure of CdS; the lattice parameters decreased as a=4.190→4.072 ? and b=c=6.790→6.635 ? with increased loading (1-10 mol%) of the Au3+ dopant. Optical spectra of AuxCd1-xS revealed a significant red-shift (485→538 nm) of the absorption onset and band edge emission (506→530 nm) with notable quenching in photoluminescence. The bandgap energy decreases (2.71→2.41 eV) with increasing Au3+ doping of the CdS nanorods along with considerable shifting of valence band (+1.13→+1.04 eV) and conduction band positions (-1.58→-1.36 eV) versus NHE. The surface area of bare CdS (90.56 m2 g-1) is gradually reduced to 12.32 m2 g-1 with increasing Au3+ doping content. The photocatalytic activity considerably improves with doping, where the Au0.1Cd0.9S composite displays the highest levels of photooxidation (95%) of 0.5 mM salicyldehyde and reduction of 5 mM m-dinitrobenzene to m-nitroaniline (44 %) and m-phenylenediamine (52 %) relative to bare CdS (50 %) probably due to the homogeneous dispersion of Au3+ ions throughout CdS crystal, their superior band-energetics for facile charge-separation and better photostability.
- Singh, Rohit,Pal, Bonamali
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p. 851 - 858
(2015/05/13)
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- Highly dispersed Au, Ag and Cu nanoparticles in mesoporous SBA-15 for highly selective catalytic reduction of nitroaromatics
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This paper demonstrates a homogeneous dispersion of 4 wt% coinage metal nanoparticles (Au, Ag and Cu) of different morphologies in the pores (～8 nm) of 3-aminopropyltriethoxysilane (APTES) modified mesoporous SBA-15 for selective catalytic reduction of m-dinitrobenzene to phenylenediamine. EDX, elemental mapping and HR-TEM analysis confirmed the uniform dispersal of metal nanoparticles within the mesoporous matrix having lattice fringes with a d-spacing of 0.232 nm for Au (111), 0.23 nm and 0.20 nm for Ag (111) and (200) and 0.25 nm for CuO (111) planes. XPS results illustrated the presence of Au and Ag in their metallic states whereas Cu was oxidized to CuO. XRD, TEM and surface area analysis revealed that formation of metal nanoparticles within the sieves led to a significant change in the surface structural and physicochemical properties. Metal nanospheres with increasing size i.e., ～5 nm (Au) 2 g-1), exhibited the best catalytic activity for m-dinitrobenzene reduction (k = 1.765 × 10-1 min-1) with 89% selectivity to m-phenylenediamine.
- Sareen, Shweta,Mutreja, Vishal,Singh, Satnam,Pal, Bonamali
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p. 184 - 190
(2015/02/03)
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- Iron and palladium(II) phthalocyanines as recyclable catalysts for reduction of nitroarenes
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Iron(II) and palladium(II) phthalocyanines have been established as recyclable heterogeneous catalysts for the reduction of aromatic nitro compounds to corresponding amines using diphenylsilane/sodium borohydride as hydrogen sources in ethanol. Various reducible functional groups, such as acetyl, ester, cyano, amide, sulphonamide and carboxylic acid etc. were well tolerated, and the methods were applicable up to gram scale. Mechanistic studies showed that reduction of nitro group proceed through direct (nitroso) pathway and possibly iron or palladium phthalocyanines activates nitro group for reduction. FePc and PdPc also catalyzed the generation of hydrogen from the combination of diphenylsilane/sodium borohydride and ethanol.
- Verma, Praveen Kumar,Bala, Manju,Thakur, Kavita,Sharma, Upendra,Kumar, Neeraj,Singh, Bikram
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p. 1258 - 1267
(2014/07/21)
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- 100% selective yield of m-nitroaniline by rutile TiO2 and m-phenylenediamine by P25-TiO2 during m-dinitrobenzene photoreduction
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Photoreduction of m-dinitrobenzene (25 μmol) in the deaerated aqueous iso-propanol exhibits 100% selective yield of m-nitroaniline (25 μmol) by rutile TiO2 (50 mg) or m-phenylenediamine (25 μmol) by P25-TiO2 separately under 8 and 4 h of UV light irradiation (125 W Hg arc, 10.4 mW/cm2), respectively. It revealed that insertion of a second -NO2 in nitrobenzene ring has an important role in expediting -NO2 reduction to -NH2 as compared to a negligible reduction of nitrobenzene under similar conditions, indicating that electron withdrawing groups lower the electron density on -NO2 present on meta position and favor quick reduction of the -NO2 group.
- Kaur, Jaspreet,Pal, Bonamali
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- Gold supported on titania for specific monohydrogenation of dinitroaromatics in the liquid phase
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Liquid-phase selective monohydrogenation of various substituted dinitroaromatics to the corresponding valuable nitroanilines was investigated on gold-based catalysts. Special attention was paid to the effect of Au particle size on this monoreduction reaction. Interestingly, TiO2 supported gold catalysts containing a relatively larger mean Au particle size (>5 nm) showed far superior chemoselectivity for specific mono-hydrogenation of dinitroaromatics, with the highest performance attainable for the catalyst bearing Au particles of ca. 7.5 nm. Results in the intermolecular competitive hydrogenation showed that the intrinsic higher accumulation rates of the desired nitroanilines associated with the catalyst possessing larger Au particles were responsible for the high chemoselectivity observed. the Partner Organisations 2014.
- Liu, Shuang-Shuang,Liu, Xiang,Yu, Lei,Liu, Yong-Mei,He, He-Yong,Cao, Yong
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supporting information
p. 4162 - 4169
(2014/09/29)
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- Metal-free transfer hydrogenation of nitroarenes in water with vasicine: Revelation of organocatalytic facet of an abundant alkaloid
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Vasicine, an abundantly available quinazoline alkaloid from the leaves of Adhatoda vasica, has been successfully employed for metal- and base-free reduction of nitroarenes to the corresponding anilines in water. The method is chemoselective and tolerates a wide range of reducible functional groups, such as ketones, nitriles, esters, halogens, and heterocyclic rings. Dinitroarenes reduced selectively to the corresponding nitroanilines under the present reaction conditions.
- Sharma, Sushila,Kumar, Manoranjan,Kumar, Vishal,Kumar, Neeraj
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p. 9433 - 9439
(2014/12/11)
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- Polymethylhydrosiloxane derived palladium nanoparticles for chemo- and regioselective hydrogenation of aliphatic and aromatic nitro compounds in water
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Chemo- and regioselective hydrogenation of a wide range of aliphatic, unsaturated, aromatic and heteroaromatic nitro compounds into their corresponding amines has been achieved with highly efficient polysiloxane-stabilised "Pd" nanoparticles on NAP-magnesium oxide supports using an environmentally friendly hydrogenating agent, polymethylhydrosiloxane [PMHS] in water. Highly stable and active Pd nanoparticles were prepared by the reduction of NAP-Mg-PdCl4 with PMHS, which serves as a reducing agent as well as a capping agent. The well-dispersed palladium nanoparticles on NAP-MgO catalysts also exhibit excellent regioselectivity in the hydrogenation of dinitrobenzenes to the corresponding nitroanilines. The catalyst has high durability against sintering during the hydrogenation reaction and can be reused with no loss in its activity. This journal is the Partner Organisations 2014.
- Damodara, Dandu,Arundhathi, Racha,Ramesh Babu, T. Venkata,Legan, Margaret K.,Kumpaty, Hephzibah J.,Likhar, Pravin R.
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p. 22567 - 22574
(2014/06/23)
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- Solid supported rhodium(0) nanoparticles: An efficient catalyst for chemo- and regio-selective transfer hydrogenation of nitroarenes to anilines under microwave irradiation
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A Solid-supported rhodium(0) (SS-Rh) catalyst has been developed and applied for the chemo- and regio-selective reduction of nitroarenes functionalized with CC multiple bonds and dinitroarenes to their corresponding amines respectively using hydrazine hydrate (N2H4· H2O) as a reducing source under mild microwave irradiation (MWI) conditions. The present methodology also shows excellent compatibility with a broad range of structurally diverse reducible functional groups. The catalyst can be recovered by simple filtration and reused for 13 cycles with consistent activity hence reduces the cost of the catalyst assertively.
- Guha, Nitul Ranjan,Bhattacherjee, Dhananjay,Das, Pralay
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supporting information
p. 2912 - 2916
(2014/05/06)
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- Highly efficient and chemoselective transfer hydrogenation of nitroarenes at room temperature over magnetically separable Fe-Ni bimetallic nanoparticles
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A highly chemoselective catalytic transfer hydrogenation (CTH) of nitroarenes to corresponding amino derivatives is achieved with Fe-Ni bimetallic nanoparticles (Fe-Ni NP's) as the catalyst and NaBH4 at room temperature. Their catalytic efficiency is ascribed to the presence of Ni sites on the bimetallic surface that not only hinder the surface corrosion of the iron sites but also facilitate efficient electron flow from the catalyst surface to the adsorbed nitro compounds. This facet is corroborated with reusability studies as well as surface characterization of the catalyst before and after its repetitive usage. Thus, these nanoparticles efficiently catalyze the reduction of functionalized nitroarenes to corresponding amines without use of corrosive agents like base or other additives under ambient conditions and are easily separated by a laboratory magnet in an eco-friendly manner.
- Petkar, Dhananjay R.,Kadu, Brijesh S.,Chikate, Rajeev C.
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p. 8004 - 8010
(2014/02/14)
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- One-pot synthesis of N-aryl propargylamine from aromatic boronic acid, aqueous ammonia, and propargyl bromide under microwave-assisted conditions
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A facile, one-pot synthesis of N-aryl propargylamine from aromatic boronic acid, aqueous ammonia, and propargyl bromide has been achieved under microwave-assisted conditions. The reactions can be smoothly completed within a total 10 min through a two-step procedure, including copper-catalyzed coupling of aromatic boronic acids with aqueous ammonia and following propargylation by propargyl bromide.
- Jiang, Yu-Bo,Zhang, Wen-Sheng,Cheng, Hui-Ling,Liu, Yu-Qi,Yang, Rui
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p. 779 - 782
(2014/06/09)
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