- Ullmann reaction of picryl bromide in the presence of ultrasound
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Ultrasonic irradiation was found to promote the Ullman coupling of picryl bromide at or below room temperature. In the presence of excess copper, a long-lived intermediate is formed that is quenched upon work-up affording variable mixtures of trinitrobenzene and picric acid.
- Nelson,Adolph
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Read Online
- Reduction of aromatic nitro compounds under solvent-free conditions using alumina-supported hydrazine/FeNH4(SO4)2· 12H2O
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Aromatic nitro compounds were easily reduced to the corresponding amino compounds with hydrazine hydrate supported on alumina in the presence of FeNH4(SO4)2·12H2O.
- Zhang, Chang-Rui,Wang, Yu-Lu,Wang, Jin-Ye
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Read Online
- THE PLATINUM CATALYZED REDUCTION OF NITROARENES TO AMINOARENES WITH CARBON MONOXIDE AND WATER
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Nitroarenes were readily transformed to aminoarenes in excellent yields under mild conditions with carbon monoxide and water in the presence of a platinum catalyst.Triethylamine, SnCl4 and PPh3 are essential for the high catalytic activity.Nitroarenes are reduced chemoselectively by this procedure.
- Watanabe, Yoshihisa,Tsuji, Yasushi,Ohsumi, Tatsuya,Takeuchi, Ryo
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Read Online
- Selective hydrodeoxygenation of acetophenone derivatives using a Fe25Ru75@SILP catalyst: a practical approach to the synthesis of alkyl phenols and anilines
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A versatile synthetic pathway for the production of valuable alkyl phenols and anilines has been developed based on the selective hydrodeoxygenation of a wide range of hydroxy-, amino-, and nitro-acetophenone derivatives as readily available substrates. Bimetallic iron ruthenium nanoparticles immobilized on an imidazolium-based supported ionic liquid phase (Fe25Ru75@SILP) act as highly active and selective catalysts for the deoxygenation of the side-chain without hydrogenation of the aromatic ring. The catalytic system allows operation under continuous flow conditions with high robustness and flexibility as demonstrated for the alternating conversion of 3′,5′-dimethoxy-4′-hydroxyacetophenone and 4′-hydroxynonanophenone as model substrates.
- Bordet, Alexis,Goclik, Lisa,Leitner, Walter,Walschus, Henrik
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supporting information
p. 2937 - 2945
(2022/04/07)
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- Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
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Paragraph 0111-0118; 0120
(2021/05/29)
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- Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex
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We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.
- Ioannou, Dimitris I.,Gioftsidou, Dimitra K.,Tsina, Vasiliki E.,Kallitsakis, Michael G.,Hatzidimitriou, Antonios G.,Terzidis, Michael A.,Angaridis, Panagiotis A.,Lykakis, Ioannis N.
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p. 2895 - 2906
(2021/02/27)
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- Efficient strategy for interchangeable roles in a green and sustainable redox catalytic system: IL/PdII-decorated SBA-15 as a mesoporous nanocatalyst
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Time and again, SBA-15-based composites as mesoporous materials and the incorporation of transition metals in them have been attracting dramatic attention in the field of catalysis due to their remarkable features. In this paper, the activity of SBA-15 supported ionic liquid-Pd(ii) has been investigated in the catalytic transfer hydrogenation of nitroarenes with formic acid as a hydrogen donor at room temperature in water medium, and the oxidation of benzyl alcohols to benzaldehyde derivatives under atmospheric oxygen at high temperature. This novel nanocatalyst was characterized by FT-IR, SA-XRD, BET, BJH, TGA, FE-SEM, TEM, and ICP as the most commonplace techniques for analyzing its characteristics to be revealed as truth. Furthermore, the EDX analysis illustrates the grafting of the ionic liquid-Pd(ii) into SBA-15. The catalyst showed high stability under reaction conditions, and can be recovered and reused for at least 15 and 6 reaction runs in oxidation and reduction reactions, respectively.
- Sadeghi, Samira,Karimi, Meghdad,Radfar, Iman,Gavinehroudi, Reza Ghahremani,Saberi, Dariush,Heydari, Akbar
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p. 6682 - 6692
(2021/04/22)
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- Fabrication of palladium nanocatalyst supported on magnetic eggshell and its catalytic character in the catalytic reduction of nitroarenes in water
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Aromatic nitro compounds, which have good solubility in water, are highly toxic and non-biodegradable are one of the most important industrial pollutants and have negative effects on human health, aquatic life and the environment. Therefore, the elimination of these harmful organic compounds has become an issue of great importance. For this, in this study we have developed a palladium nanocatalyst supported on Fe3O4-coated eggshell and characterized by FT-IR, XRD, XPS, FE-SEM, TG/DTG, BET, TEM and EDS techniques (Pd-Fe3O4-ES). Also, the quantitative analysis of Pd was determined using ICP-OES. The catalytic behavior of the designed Pd-Fe3O4-ES nanocatalyst was investigated against the catalytic reduction of several highly toxic nitro compounds using NaBH4 in water at room temperature. The progress of the reduction was followed using high performance liquid chromatography (HPLC). The catalytic studies revealed that the nitro compounds were converted into the desired amines by the Pd-Fe3O4-ES nanocatalyst using a very low dose of catalyst (15 mg) and short-duration reactions (81–360 s) in aqueous medium at ambient temperature. Furthermore, the Pd-Fe3O4-ES nanocatalyst showed good catalytic stability by retaining its activity after the fifth catalytic run.
- ?al??kan, Melike,Akay, Sema,Baran, Talat,Kayan, Berkant
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- Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
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The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol % of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid.
- Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
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p. 12417 - 12422
(2021/10/12)
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- High yielding electrophilic amination with lower order and?higher order organocuprates: Application of acetone O-(4-Chlorophenylsulfonyl)oxime in the construction of the C?N bond at room temperature
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Electrophilic amination reaction was performed with lower order and?higher order organocuprates using acetone O-(4-Chlorophenylsulfonyl)oxime (1). It was proceeded smoothly at room temperature in the presence of organocuprates to provide the corresponding primary amines in good yields with 10 and 60 min, respectively. The primary amine yields of the electrophilic amination of bromomagnesium organocyanocuprates and dibromomagnesium diorganocyanocuprates were obtained 52–72% and 58–83%, respectively. We observed that higher order organocuprates were more successful than lower order organocuprates in the synthesis of functionalized arylamines by electrophilic amination.
- Duran, Serdar,Korkmaz, Adem
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p. 2077 - 2087
(2021/05/27)
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- Room-temperature copper-catalyzed electrophilic amination of arylcadmium iodides with ketoximes
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We started our study by preparation two ketoximes. Later, there were studies to reveal these ketoximes' effects in the electrophilic amination reaction with organocadmium reagents. Primarily, it was observed that arylcadmium iodides could not be reacted with ketoximes at room temperature in the absence of a catalyst. CuCN was a suitable catalyst for this electrophilic amination reaction of arylcadmium iodides and allowed the preparation of functionalized aniline derivatives in good yields under mild reaction conditions. We obtained the results indicated that the yield of primary arylamines was strongly dependent on the steric and electronic effects of organocadmium reagent and amination agent. In the case of both amination reagents, meta-substituted arylamines were obtained in higher yields than para-substituted arylamines. We observed that acetone O-(4-chlorophenylsulfonyl)oxime, 1, as an aminating agent, was more successful than acetone O-(2-Naphthylsulfonyl)oxime, 2, in the synthesis of functionalized arylamines by electrophilic amination of corresponding aryl cadmium iodides. In this method, there is no cadmium release to the environment.
- Korkmaz, Adem
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p. 3119 - 3125
(2021/05/10)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Adhesive functionalized ascorbic acid on CoFe2O4: A core-shell nanomagnetic heterostructure for the synthesis of aldoximes and amines
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This paper reports on the simple synthesis of novel green magnetic nanoparticles (MNPs) with effective catalytic properties and reusability. These heterogeneous nanocatalysts were prepared by the anchoring of Co and V on the surface of CoFe2O4 nanoparticles coated with ascorbic acid (AA) as a green linker. The prepared nanocatalysts have been identified by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray atomic mapping, thermogravimetric analysis, X-ray powder diffraction, vibrating sample magnetometer analysis, coupled plasma optical emission spectrometry and Fourier transform infrared spectroscopy. The impact of CoFe2O4@AA-M (Co, V) was carefully examined for NH2OH·HCl oximation of aldehyde derivatives first and then for the reduction of diverse nitro compounds with sodium borohydride (NaBH4) to the corresponding amines under green conditions. The catalytic efficiency of magnetic CoFe2O4@AA-M (Co, V) nanocatalysts was investigated in production of different aldoximes and amines with high turnover numbers (TON) and turnover frequencies (TOF) through oximation and reduction reactions respectively. Furthermore, the developed environment-friendly method offers a number of advantages such as high turnover frequency, mild reaction conditions, high activity, simple procedure, low cost and easy isolation of the products from the reaction mixture by an external magnetic field and the catalyst can be reused for several consecutive runs without any remarkable decrease in catalytic efficiency.
- Sorkhabi, Serve,Ghadermazi, Mohammad,Mozafari, Roya
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p. 41336 - 41352
(2020/11/30)
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- Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives
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A highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene. Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Manzoli, Maela,Cravotto, Giancarlo
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supporting information
p. 2689 - 2700
(2020/05/18)
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- Enhanced catalytic activity of natural hematite-supported ppm levels of Pd in nitroarenes reduction
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In this work, Pd NPs supported on amine-modified natural hematite have been prepared and characterized. Using this simple catalyst, nitroaromatic compounds as a major cause of industrial pollution were reduced to corresponding amines with ppm levels of Pd in the presence of designer surfactant TPGS-750-M and NaBH4 at room temperature in aqueous media. Synergistic effect between hematite and Pd is responsible for the observed enhanced catalytic activity. This catalyst was recycled for at least four times with a small decrease in the activity.
- Gholinejad, Mohammad,Shojafar, Mohammad,Sansano, José M.
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p. 2033 - 2043
(2020/04/07)
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- Synthesis method of aminobenzoate compound (by machine translation)
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The synthesis method comprises the following steps: carrying out a hydrogenation reduction reaction of a nitroanisole compound with a carbon-coated nickel containing alkaline earth metal in a hydrogen atmosphere; wherein the shell layer is a graphitized carbon layer containing alkaline earth metal, nitrogen and oxygen. To the method, the alkaline earth metal-containing carbon-coated nano composite material is used as a catalyst, the carbon material and the nickel nanoparticles cooperate to play a good catalytic effect, and the alkaline earth metal of the shell layer further synergistically improves the catalytic performance of the material. (by machine translation)
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Paragraph 0094-0096; 0134-0136
(2020/08/09)
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- Synthesis method of amino-anisole compound
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The invention provides a synthesis method of an amino-anisole compound. The synthesis method comprises the following steps: taking a carbon-coated nickel nano composite material containing alkali metals as a catalyst, and catalyzing a hydrogenation reduction reaction of a nitro-anisole compound in a hydrogen atmosphere; wherein the nano composite material contains a core-shell structure with a shell layer and an inner core, the shell layer is a graphitized carbon layer containing alkali metals, nitrogen and oxygen, and the inner core is nickel nano particles. According to the method, the nanocomposite material is used as a catalyst; a carbon material and the nickel nano particles generate a synergistic effect and a good catalytic effect, the alkali metals of the shell layer further synergistically improve the catalytic performance of the nano composite material, and the catalyst is used for hydrogenation reduction of nitro-anisole compounds to synthesize amino-anisole compounds, and has excellent activity, selectivity and safety.
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Paragraph 0144-0146
(2020/08/09)
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- Synthesis method of amino-anisole compound
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The invention provides a synthesis method of an amino-anisole compound. The synthesis method comprises the following steps: taking a carbon-coated nickel nano composite material containing alkali metals as a catalyst, and catalyzing a hydrogenation reduction reaction of a nitro-anisole compound in a hydrogen atmosphere; wherein the nano composite material contains a core-shell structure with a shell layer and an inner core, the shell layer is a graphitized carbon layer containing alkali metals and oxygen, and the inner core is nickel nano particles. According to the method, the nano compositematerial is used as a catalyst; a carbon material and the nickel nano particles generate a synergistic effect and a good catalytic effect, the alkali metals of the shell layer further synergisticallyimprove the catalytic performance of the nano composite material, and the catalyst is used for hydrogenation reduction of nitro-anisole compounds to synthesize amino-anisole compounds, and has excellent activity, selectivity and safety.
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Paragraph 0057; 0151-0153
(2020/08/09)
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- 1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
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The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
- Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
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p. 3583 - 3594
(2020/09/15)
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- Heterogeneous photocatalysis of azides: Extending nitrene photochemistry to longer wavelengths
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The photodecomposition of azides to generate nitrenes usually requires wavelengths in the 300 nm region. In this study, we show that this reaction can be readily performed in the UVA region (368 nm) when catalyzed by Pd-decorated TiO2. In aqueous medium the reaction leads to amines, with water acting as the H source; however, in non-protic and non-nucleophilic media, such as acetonitrile, nitrenes recombine to yield azo compounds, while azirine-mediated trapping occurs in the presence of nucleophiles. The heterogeneous process facilitates catalyst separation while showing great chemoselectivity and high yields.
- Argüello, Juan E.,Lanterna, Anabel E.,Lemir, Ignacio D.,Scaiano, Juan C.
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supporting information
p. 10239 - 10242
(2020/10/02)
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- One-Pot Generation of Benzynes from Phenols: Formation of Primary Anilines by the Deoxyamination of Phenols
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Benzynes were selectively generated in situ from phenols and trapped regioselectively with potassium hexamethyldisilazide to form primary anilines following acidic workup. The direct conversion of a phenolic hydroxyl group into a free amino group is a useful method for the preparation of primary aryl amines that are hard to synthesize by using coupling reactions involving phenol derivatives with ammonia. Whereas reactions of ortho- and meta-substituted phenols produced meta-substituted anilines exclusively, those of para-substituted phenols provided ortho-silylanilines.
- Akai, Shuji,Ikawa, Takashi,Masuda, Shigeaki
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- The immobilized Ni(II)-thiourea complex on silica-layered copper ferrite: A novel and reusable nanocatalyst for one-pot reductive-acetylation of nitroarenes
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In this study, magnetically nanoparticles of CuFe2O4@SiO2@PTMS@Tu@Ni(II) as novel and reusable catalyst were prepared. Synthesis of the Ni (II)-nanocatalyst was carried out through the complexation of Ni(OAc)2·4H2O with the immobilized thiourea on silica-layered CuFe2O4. The prepared nanocomposite system was then characterized using SEM, EDX, XRD, VSM, ICP-OES, Raman, UV–Vis and FT-IR analyses. Catalytic activity of the Ni(II)-CuFe2O4 system was investigated towards rapid reduction of aromatic nitro compounds to arylamines with sodium borohydride as well as one-pot reductive-acetylation of nitroarenes to acetanilides with NaBH4/Ac2O system without the isolation of intermediate arylamines. All reactions were carried out in H2O within 3–7?min to afford the products arylamines/acetanilides in high to excellent yields. Reusability of the Ni(II)-nanocatalyst was examined for seven consecutive cycles without the significant loss of the catalytic activity.
- Zeynizadeh, Behzad,Shokri, Zahra,Hasanpour Galehban, Morteza
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- Utilization of a Hydrogen Source from Renewable Lignocellulosic Biomass for Hydrogenation of Nitroarenes
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Exploring of hydrogen source from renewable biomass, such as glucose in alkaline solution, for hydrogenation reactions had been studied since 1860s. According to proposed pathway, only small part of hydrogen source in glucose was utilized. Herein, the utilization of a hydrogen source from renewable lignocellulosic biomass, one of the most abundant renewable sources in nature, for a hydrogenation reaction is described. The hydrogenation is demonstrated by reduction of nitroarenes to arylamines in up to 95 % yields. Mechanism studies suggest that the hydrogenation occurs via a hydrogen transformation pathway.
- Tan, Fang-Fang,Tang, Kai-Li,Zhang, Ping,Guo, Yan-Jun,Qu, Mengnan,Li, Yang
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p. 4189 - 4195
(2019/03/07)
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- Photocatalytic hydrogenation of nitroarenes: supporting effect of CoOx on TiO2 nanoparticles
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Cobalt oxide visible light-active photo-catalysts supported on TiO2 nanoparticles with varying amount of cobalt oxide [3% CoOx/TiO2 (A), 4% CoOx/TiO2 (B), 5% CoOx/TiO2 (C)] were synthesized by solid-state method followed by calcination. The as-synthesized catalysts were characterized by various techniques such as powder XRD, TEM, EDX, UV-Vis-DRS and XPS analysis. The photocatalytic activity of the as-synthesized materials was studied for the reduction of nitroarenes to the corresponding amines using hydrazine monohydrate as the reductant. Cobalt(ii) oxide is responsible for the reduction of nitroarenes and then, cobalt(iii) is reduced back to the original compound by hydrazine hydrate, thus ascertaining the catalytic nature of this hydrogenation process. XPS suggests the presence of Co(ii) in CoOx/TiO2.
- Amanchi, Srinivasa Rao,Ashok Kumar,Lakshminarayana, Bhairi,Satyanarayana,Subrahmanyam
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p. 748 - 754
(2019/01/10)
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- Novel Biomass-Derived Fe3O4@Pd NPs as Efficient and Sustainable Nanocatalyst for Nitroarene Reduction in Aqueous Media
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Abstract: A novel magnetically recyclable nitrogen-doped Fe3O4@Pd NPs was prepared from the biomass-based materials which was employed as carbon and nitrogen source. The as-prepared catalysts were fully characterized by a variety of physicochemical techniques and were exploited for nitroaromatic hydrogenation with broad scope and excellent chemoselectivity using molecular hydrogen as a reductant. The heterogeneous catalysts can be recovered easily and reused for at least eight recycling reactions without obviously loss of catalytic properties. In addition, using this protocol, the key intermediate of marketed drug Osimertinib could be synthesized easily. Graphical Abstract: [Figure not available: see fulltext.].
- Zhao, Linwei,Zheng, Kai,Tong, Jianying,Jin, Jianzhong,Shen, Chao
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p. 2607 - 2613
(2019/06/08)
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- Mild and efficient synthesis of secondary aromatic amines by one-pot stepwise reductive amination of arylaldehydes with nitroarenes promoted by reusable nickel nanoparticles
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The one-pot stepwise reductive amination of arylaldehydes with nitroarenes is described, using reusable nickel nanoparticles (Ni-pol) as catalyst and NaBH4 as mild, inexpensive, and safe reducing agent. The proposed catalytic system holds several advantages such as the use of a non-precious and earth-abundant metal, the facile separation of the catalyst from the reaction mixture by centrifugation, excellent stability towards air and moisture, very mild reaction conditions, good recyclability, broad substrate scope with good to excellent yields, and easy scalability (up to 1.0 g). FESEM analyses indicate that the active species are cubic nanocrystals of Ni in the average cross section value of 35 nm with a quite narrow (25–45 nm) and monomodal distribution, which becomes bimodal with the recycling reactions but without agglomeration.
- Fiore, Ambra Maria,Romanazzi, Giuseppe,Dell'Anna, Maria Michela,Latronico, Mario,Leonelli, Cristina,Mali, Matilda,Rizzuti, Antonino,Mastrorilli, Piero
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- Palladium Nanoparticles on a Creatine-Modified Bentonite Support: An Efficient and Sustainable Catalyst for Nitroarene Reduction
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Creatine as the nitrogen-rich, green and cheap compound is used for modification of natural bentonite and the resulting material is employed for the stabilization of Palladium nanoparticles having an average diameter of 3 nm. This new material bento-crt@Pd is characterized using different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), solid state UV-vis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX). This green catalyst promotes efficient reduction of aromatic nitro compounds in aqueous media. By using this catalyst nitroarenes having electron donating as well as electron withdrawing groups were reduced efficiently to their corresponding amines at room temperature. The catalyst can be recycled seven times and the reused catalyst was characterized by TEM and XPS.
- Gholinejad, Mohammad,Rasouli, Zahra,Najera, Carmen,Sansano, José M.
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p. 1122 - 1129
(2019/09/06)
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- Eco-friendly hydrogenation of aryl azides to primary amines on graphene oxide-decorated bimetallic Rh-Pt nanoparticles (RhPt@GO NPs)
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Graphene oxide-supported rhodium/platinum (Rh-Pt) nanoparticles (Rh-Pt@GO NPs) are a promising catalyst for the reduction of aryl azides to primary amines. Rh-Pt@GO NPs have been produced by the microwave-assisted sonochemical method. This catalyst showed superior catalytic activity to afford quantitative yields of primary amines under an extremely mild condition in the presence of sodium borohydride. The synthesized novel catalyst was easily recovered by centrifugation and reused without loss of its catalytic activity. The spectroscopic analyses of the RhPt@GO NPs indicated the formation of highly crystalline, monodisperse, and colloidally stable RhPt@GO NPs.
- Kilbas, Benan,Kara, Belguzar Yasemin
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- Microballs Containing Ni(0)Pd(0) Nanoparticles for Highly Selective Micellar Catalysis in Water
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Both Ni(0) complexes and nanoparticles (NPs) are unstable in water, which poses a significant hindrance to their application in aqueous synthetic catalysis. To overcome these barriers, ligated Ni(0) nanoparticles (diameter 1 nm) containing a minimum amount of Pd(0) in the microballs formed of amphiphile PS-750-M are developed and applied in the highly selective carbamate cleavage. Selectivity and functional group tolerance are thoroughly investigated. Control experiments revealed the importance of an individual component of the nanocatalyst. Use of our proline-based amphiphile PS-750-M is critical for achieving microball architecture, the stability of nanoparticles, and desired catalytic activity. Once formed, microballs can be isolated and stored at ambient temperature. Catalyst is thoroughly characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis, infrared, and cyclic voltammetry. For selective catalysis, zero oxidation state of both Ni and Pd is crucial. On the basis of catalyst characterization and control experiments, the plausible reaction mechanism is proposed.
- Bihani, Manisha,Bora, Pranjal P.,Nachtegaal, Maarten,Jasinski, Jacek B.,Plummer, Scott,Gallou, Fabrice,Handa, Sachin
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p. 7520 - 7526
(2019/08/15)
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- Copper-catalyzed arene amination in pure aqueous ammonia
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A simple protocol for copper-catalyzed arene amination using aqueous ammonia without any additional ligands and organic coordinating solvents has been developed. The reaction pathway via a Cu(i)/Cu(iii) mechanism is proposed based on the results of control experiments as well as DFT calculations.
- Takagi, Mio,Watanabe, Ayako,Murata, Shigeo,Takita, Ryo
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supporting information
p. 1791 - 1795
(2019/02/20)
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- AMINATION AND HYDROXYLATION OF ARYLMETAL COMPOUNDS
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In one aspect, the present disclosure provides methods of preparing a primary or secondary amine and hydroxylated aromatic compounds. In some embodiments, the aromatic compound may be unsubstituted, substituted, or contain one or more heteroatoms within the rings of the aromatic compound. The methods described herein may be carried out without the need for transition metal catalysts or harsh reaction conditions.
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Paragraph 0098; 0134; 0135; 0164
(2018/03/25)
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- A fragrant amines for the preparation of compounds (by machine translation)
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The invention discloses a fragrant amines preparation method of the compound, the method in a certain amount of supported cobalt-containing catalyst and a certain amount of fragrant nitryl compounds added in the reactor, then adding ammonium formate, and tetrahydrofuran mixed solvent with water, under stirring, the reaction temperature is 80 - 200 °C, reaction 0.5 - 24 h, to get the corresponding sweet-smelling amines compound. According to the preparation method of this invention the use of inexpensive, renewable bamboo shoots as raw materials for preparing carbon precursor, environmental protection, simple and easy to obtain, without adding nitrogen source material; at the same time in order to triphenylphosphine as the phosphorus source, low price. The substituted ammonium hydrogen as the reducing agent, the operation is simple, mild reaction conditions, in particular to an easily reducible functional group containing fragrant nitryl compounds for chemical selectivity can be controlled more easily. (by machine translation)
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Paragraph 0041-0045
(2018/11/10)
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- Synthesis, characterization, and application of easily accessible resin-encapsulated nickel nanocatalyst for efficient reduction of functionalized nitroarenes under mild conditions
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Abstract: A novel resin-encapsulated nickel nanocatalyst has been synthesized by a modified impregnation method using nickel acetate tetrahydrate in presence of sodium borohydride as a mild reducing agent. The synthesized nanocatalyst was characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The concentration of nickel nanoparticles encapsulated on resin was determined by inductively coupled plasma-mass spectroscopy (ICP-MS). Further, synthesized resin-encapsulated nickel nanocatalyst was found to be stable and efficient in micromolar concentrations, for the selective reduction of functionalized nitroarenes to corresponding amines in good to high yield, under mild reaction conditions. The nanocatalyst shows excellent reusability. Graphical Abstract: SYNOPSIS A novel resin-encapsulated nickel nanocatalyst (Ni@XAD-4) was synthesized using a modified impregnation method. The nanocatalyst exhibited excellent catalytic activity towards the selective reduction of functionalized nitroarenes in the presence of NaBH 4 with reusability up to five cycles.[Figure not available: see fulltext.].
- Rani, Poonam,Singh, Kamal Nain,Kaur, Amarjit
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- Polymer supported Nickel nanoparticles as recyclable catalyst for the reduction of nitroarenes to anilines in aqueous medium
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Polymer supported nickel nanoparticles, generated by calcination under nitrogen of a Ni(II) containing polyacrylamide, catalyzed the hydrogenation of nitroarenes to anilines in aqueous medium at room temperature in the presence of NaBH4. The protocol generally favored the formation of the desired aniline as single product in high yields with short reaction times and proved to be highly selective in the hydrogenation of halonitrobenzene to haloaniline, avoiding the formation of hydro-dehalogenated side-products. The catalyst displayed excellent recyclability over at least five cycles (which is not trivial for nickel nanoparticle based catalysts used in water) and no leaching of metal into solution occurred, that made the overall system eco-friendly and economic. STEM analyses revealed that the thermally formed Ni nanoparticles turned into cubic nanotwins under reaction conditions, which remained almost unchanged with the re-cycles.
- Romanazzi, Giuseppe,Fiore, Ambra Maria,Mali, Matilda,Rizzuti, Antonino,Leonelli, Cristina,Nacci, Angelo,Mastrorilli, Piero,Dell'Anna, Maria Michela
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- Enhanced catalytic performance of cobalt nanoparticles coated with a N,P-codoped carbon shell derived from biomass for transfer hydrogenation of functionalized nitroarenes
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The development of abundantly available base metal catalysts for organic transformations remains an important goal of chemical research. Herein, we report the first facile fabrication of active, inexpensive, and reusable cobalt nanoparticles (NPs) coated with a N,P-codoped carbon shell derived from naturally renewable biomass and earth-abundant, low-cost cobalt salt and PPh3. The entire process is operationally simple, straightforward, cost-effective and environmentally benign and can be used in mass production for practical application. The resultant catalysts allow for highly efficient and selective transfer hydrogenation of functionalized nitroarenes to the corresponding anilines using formic acid or ammonium formate as the hydrogen donor. Uniformly incorporated N and P into the carbon lattices exhibited synergistic effects with the encapsulated Co NPs to engineer the structure and composition of the catalyst, thereby substantially boosting the catalytic efficiency. The most active catalyst Co@NPC-800 exhibited outstanding activity and exclusive selectivity for the reduction of functionalized nitroarenes to anilines, especially those decorated with readily reducible functional groups. The catalyst demonstrated high stability and can be easily separated by using an external magnet for successive reuses without significant loss in both activity and selectivity.
- Duan, Yanan,Song, Tao,Dong, Xiaosu,Yang, Yong
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supporting information
p. 2821 - 2828
(2018/06/29)
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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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- A practical and highly efficient transfer hydrogenation of aryl azides using a [Ru(p-cymene)Cl2]2 catalyst and sodium borohydride
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Various aniline derivatives were synthesized by selective reduction of aryl azides in the presence of a dichloro(p-cymene)ruthenium(II) dimer ([Ru(p-cymene)Cl2]2) via hydrolysis of sodium borohydride. The hydrogenation reactions were carried out in aqueous media at room temperature. Most of the reactions were completed within 10 min with quantitative yields.
- Kilbas, Benan,Yilmaz, Yunus Emre,Ergen, Sinem
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p. 880 - 883
(2018/08/21)
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- Investigation of hydro-lipophilic properties of n-alkoxyphenylhydroxynaphthalenecarboxamides ?
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The evaluation of the lipophilic characteristics of biologically active agents is indispensable for the rational design of ADMET-tailored structure–activity models. N-Alkoxy-3-hydroxynaphthalene-2-carboxanilides, N-alkoxy-1-hydroxynaphthalene-2-carboxanilides, and N-alkoxy-2-hydroxynaphthalene-1-carboxanilides were recently reported as a series of compounds with antimycobacterial, antibacterial, and herbicidal activity. As it was found that the lipophilicity of these biologically active agents determines their activity, the hydro-lipophilic properties of all three series were investigated in this study. All 57 anilides were analyzed using the reversed-phase high-performance liquid chromatography method for the measurement of lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, a range of software lipophilicity predictors for the estimation of clogP values of a set of N-alkoxyphenylhydroxynaphthalenecarboxamides was employed and subsequently cross-compared with experimental parameters. Thus, the empirical values of lipophilicity (logk) and the distributive parameters (π) were compared with the corresponding in silico characteristics that were calculated using alternative methods for deducing the lipophilic features. To scrutinize (dis)similarities between the derivatives, a PCA procedure was applied to visualize the major differences in the performance of molecules with respect to their lipophilic profile, molecular weight, and violations of Lipinski’s Rule of Five.
- Kapustikova, Iva,Bak, Andrzej,Gonec, Tomas,Kos, Jiri,Kozik, Violetta,Jampilek, Josef
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- Ethyl 6-Hydroxyfulvene-1-Carboxylate: A Reagent Discriminating Primary Amines from Secondary Amines
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A highly chemo-selective reaction was observed when ethyl 6-hydroxyfulvene-1-carboxylate 1 was treated with different nucleophiles such as primary amines, secondary amines, alcohols, and thiols. Among them, only primary amines are reactive toward 1 to afford the condensation products 3, which exhibit good stability under both weakly acidic and basic conditions. The condensation process proved to be reversible between different primary amines. On the basis of this observation, the chemical selectivity of typical primary aromatic amines was evaluated quantitatively by determining equilibrium constants of the condensation reactions with aniline as a reference. Moreover, the primary amines of 3 can be readily released upon treatment with aqueous ammonia, making 6-hydroxyfulvene-1-carboxylate 1 a promising protecting reagent for primary amines.
- Yang, Sen,Lu, Dengfu,Zhu, Yuequan,Shi, Mei,Luo, Fan,Gong, Yuefa
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p. 6681 - 6689
(2018/06/11)
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- Controlled Transformations of Aryl Halides in a Flow System: Selective Synthesis of Aryl Azides and Aniline Derivatives
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Copper-mediated nitrogenation of aryl halides with sodium azide can result in either aryl azides or aniline derivatives. The selectivity of the transformation is highly dependent on reaction time and temperature, which led to contradictory literature results with respect to product selectivity and the conditions applied. The advantages of a strictly controlled flow reactor environment were exploited in order to facilitate selective haloarene transformations. Reaction conditions were carefully investigated to understand their role on product selectivity. Aryl azides and aryl amines were successfully prepared from the same starting materials using the same auxiliaries by means of precise control over residence time and reaction temperature, thereby ensuring time-, cost- and atom-efficient syntheses. (Figure presented.).
- Georgiádes, ádám,?tv?s, Sándor B.,Fül?p, Ferenc
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p. 1841 - 1849
(2018/04/09)
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- Use of Catalytic Static Mixers for Continuous Flow Gas-Liquid and Transfer Hydrogenations in Organic Synthesis
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Catalytic static mixers were used for the continuous flow hydrogenation of alkenes, alkynes, carbonyls, nitro- and diazo-compounds, nitriles, imines, and halides. This technique relies on tubular reactors fitted with 3D printed static mixers which are coated with a catalytic metal layer, either Pd or Ni. Additive manufacturing of the metal mixer scaffold results in maximum design flexibility and is compatible with deposition methods such as metal cold spraying which allow for mass production and linear process scale up. High to full conversion was achieved for the majority of substrates, demonstrating the flexibility and versatility of the catalytic static mixer technology. In the example of an alkyne reduction, the selectivity of the flow reactor could be directed to either yield an alkene or alkane product by simply changing the reactor pressure.
- Hornung, Christian H.,Nguyen, Xuan,Carafa, Antony,Gardiner, James,Urban, Andrew,Fraser, Darren,Horne, Mike D.,Gunasegaram, Dayalan R.,Tsanaktsidis, John
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p. 1311 - 1319
(2017/09/23)
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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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- Polyfunctional imidazoles: XIII.1 Addition and cyclization reactions of 1-aryl-4-chloro-5-(2-nitroethenyl)-1H-imidazoles with sulfur and nitrogen nucleophiles
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1-Aryl-4-chloro-5-(2-nitroethenyl)-1H-imidazoles reacted with thiols and aromatic amines via Michael addition to give 5-[(1-arylsulfanyl)-2-nitroethyl)]-4-chloro-1H-imidazoles and N-[1-(1-aryl-4-chloro-1H-imidazol-5-yl)-2-nitroethyl]anilines, respectively
- Chornous,Mel’nik, O. Ya.,Grozav,Suikov, S. Yu.,Vovk
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p. 407 - 412
(2017/05/10)
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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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- Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds
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Arylmetals are highly valuable carbon nucleophiles that are readily and inexpensively prepared from aryl halides or arenes and widely used on both laboratory and industrial scales to react directly with a wide range of electrophiles. Although C-C bond formation has been a staple of organic synthesis, the direct transfer of primary amino (-NH2) and hydroxyl (-OH) groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge because of the absence of suitable heteroatom-transfer reagents. Here, we demonstrate the use of bench-stable N-H and N-alkyl oxaziridines derived from readily available terpenoid scaffolds as efficient multifunctional reagents for the direct primary amination and hydroxylation of structurally diverse aryl- and heteroarylmetals. This practical and scalable method provides one-step synthetic access to primary anilines and phenols at low temperature and avoids the use of transition-metal catalysts, ligands and additives, nitrogen-protecting groups, excess reagents and harsh workup conditions.
- Gao, Hongyin,Zhou, Zhe,Kwon, Doo-Hyun,Coombs, James,Jones, Steven,Behnke, Nicole Erin,Ess, Daniel H.,Kürti, László
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p. 681 - 688
(2017/06/30)
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- Stable and reusable platinum nanocatalyst: An efficient chemoselective reduction of nitroarenes in water
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Binaphthyl stabilized Pt nanoparticles (Pt-BNP) have been synthesized, characterized, and utilized as an efficient heterogeneous catalyst for chemoselective reduction of nitroarenes at room temperature in water. Several sensitive functional groups like ketone, ester, acid, amide, halides, and nitrile were well tolerated in this chemoselective reduction. The Pt-BNP catalyst was quantitatively recovered without any major change in particle size and reactivity and then efficiently reused for five catalytic cycles.
- Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
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supporting information
p. 1410 - 1413
(2016/03/12)
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- RuII, IrIII and OsII mesoionic carbene complexes: Efficient catalysts for transfer hydrogenation of selected functionalities
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Pyridine-appended triazolylidene donors have been recently used as ligands in various homogeneous catalytic processes. We present here a new pyrimidine substituted triazolium salt which was prepared and used in the coordination to RuII and OsII. The new triazolium salt and the obtained complexes were characterized by multinuclear NMR spectroscopy. The molecular composition of the mentioned compounds was confirmed by positive ion electrospray ionization (ESI+) mass spectra. The new pyrimidyl containing complexes, as well as the related pyridyl-triazolylidene containing complexes, were applied in transfer hydrogenation reactions of carbonyls, alkenes, imines and nitroarenes. The pyrimidyl containing complexes reveal an over-all better activity in comparison to their pyridine bearing analogues. The studies of electronic effects of the ligands, as well as mechanistic insights for the reduction of nitrobenzene with three selected precatalysts are presented.
- Bolje, Aljo?a,Hohloch, Stephan,Ko?mrlj, Janez,Sarkar, Biprajit
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p. 15983 - 15993
(2016/10/22)
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- Selectivity and activity in catalytic hydrogenation of azido groups over Pd nanoparticles on aluminum oxy-hydroxide
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Azidoarenes involving various functional groups were successfully reduced to aniline derivatives using commercially available aluminium oxy-hydroxide-supported palladium (Pd/AlO(OH)) nanoparticles (0.5 wt% Pd) in an aqueous medium with sodium borohydride as the hydrogen source. To develop the green process, water was utilized in conjunction with methanol. The results demonstrated that the halogen substituted azidoarenes were selectively converted to the corresponding aniline compounds without dehalogenation. In general, all of the reactions were completed within 10-30 min at room temperature with yields of over 99%. In order to optimize the reaction conditions, the parametric effects of the solvent type and the amount of the catalyst/NaBH4 were examined. Consequently, for the first time, a novel, practical and environmentally friendly process was developed for the conversion of azidoarenes to aniline derivatives in the fluence of Pd/AlO(OH) nanoparticles.
- Kara, Belgüzar Yasemin,Kilba?, Benan,G?ksu, Haydar
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p. 9550 - 9555
(2016/11/11)
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- Electrophilic amination of aromatics with sodium azide in BF3-H2O
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Boron trifluoride monohydrate is an excellent Br?nsted acid catalyst system for a wide range of reactions. It is a non-oxidizing acid catalyst prepared easily by bubbling BF3 into water. We have found boron trifluoride monohydrate/sodium azide combination to be an efficient reagent system for aromatic electrophilic amination. The present method avoids the use of expensive superacids such as trifluoromethanesulfonic acid and provides a facile access to aromatic amines directly from aromatics.
- Prakash, G.K. Surya,Gurung, Laxman,Marinez, Eric R.,Mathew, Thomas,Olah, George A.
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supporting information
p. 288 - 291
(2016/01/12)
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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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- Towards a general ruthenium-catalyzed hydrogenation of secondary and tertiary amides to amines
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A broad range of secondary and tertiary amides has been hydrogenated to the corresponding amines under mild conditions using an in situ catalyst generated by combining [Ru(acac)3], 1,1,1-tris(diphenylphosphinomethyl)ethane (Triphos) and Yb(OTf)3. The presence of the metal triflate allows to mitigate reaction conditions compared to previous reports thus improving yields and selectivities in the desired amines. The excellent isolated yields of two scale-up experiments corroborate the feasibility of the reaction protocol. Control experiments indicate that, after the initial reduction of the amide carbonyl group, the reaction proceeds through the reductive amination of the alcohol with the amine arising from collapse of the intermediate hemiaminal.
- Cabrero-Antonino, Jose R.,Alberico, Elisabetta,Junge, Kathrin,Junge, Henrik,Beller, Matthias
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p. 3432 - 3442
(2016/05/19)
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- Aryl C-N bond formation by electrophilic amination of diarylcadmium reagents with O-substituted ketoximes
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Diorganocadmium reagents cannot react with ketoxime at room temperature. CuCN catalysis allows diarylcadmium reagents to react with ketoxime and to give corresponding arylamines in good to high yields at room temperature. According to the electronic effects of the substituent attached to the aromatic ring, functionalized diarylcadmium reagents show meta-para selectivity in their amination reactions. Also compared to diarylzinc reagents, diarylcadmium reagents react with O-substituted ketoxime under milder reaction conditions and they form corresponding arylamines in higher yields. CuCN cannot help dialkyl-, dicycloalky-, and dibenzylcadmium reagents to react with ketoxime. Our Aryl C-N bond formation method does not include cadmium excretion into the environment.
- Da?kapan, Tahir,Korkmaz, Adem
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supporting information
p. 813 - 817
(2016/07/06)
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