- Intermediate Formation of a ?-Alkyl Iron(III) Complex in the Reduction of 4-Nitrobenzyl Chloride catalysed by Iron(II)-porphyrins
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Formation of the ?-alkyl FeIII (TPP)(CH2C6H4NO2-4) complex (TPP = tetraphenylporphyrin) during reduction of 4-nitrobenzyl chloride (1) by sodium ascorbate catalysed by Fe(TPP)(Cl) was detected by visible spectroscopy, and its involvement as an intermediate in the reduction of (1) to 4-nitrotoluene was deduced from a study of the characteristics of this reaction.
- Mansuy, Daniel,Fontecave, Marc,Battioni, Jean-Paul
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Read Online
- Controlled growth of hexagonal Zn2GeO4 nanorods on carbon fibers for photocatalytic oxidation of p-toluidine
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In this paper, hexagonal Zn2GeO4 nanorods grown on the surface of carbon fibers (CFs) that were pre-activated by sodium hypochlorite were prepared by a facile solvothermal method. The possible growth mechanism has been investigated by theoretical calculations and a simulation experiment by growth of Zn2GeO4 on a 2D flat surface of graphene. The (113) crystal facet of Zn2GeO4 nanorods attached to the CFs surface was the most stable structure. Due to the synergistic effect between the photocatalytic activity of Zn2GeO4 and excellent adsorption capacity of CFs, the resultant Zn2GeO4/CFs composites exhibited excellent photocatalytic activity for oxidation of p-toluidine.
- Jiang, Guohua,Tang, Bolin,Chen, Hua,Liu, Yongkun,Li, Lei,Huang, Qin,Chen, Wenxing
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Read Online
- Mechanochemical nitration of toluene with metal oxide catalysts
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Results of an experimental study of the mechanochemical nitration of toluene are presented. The focus is on the effect of acidity of metal oxide catalysts on the yield of mononitrotoluene. No solvents were used during the reaction. Sodium nitrate served as a source of nitronium. Gas chromatography-mass spectrometry of the products showed that the nitration rate scaled with the catalyst's acidity and specific surface area. Homogenizing NaNO3 with the catalyst by additional milling prior to reaction with toluene led to a rapid, nearly complete nitration. Distribution of nitrate over the surface of catalyst is likely rate limiting when toluene is mechanochemically nitrated without the preliminary milling step. The observed for varied reactant ratios trends in yield and isomer ratios suggest that nitronium participates in the nitration while localized on the active sites of the catalyst. Excess of toluene blocks acid sites, inhibiting the formation of nitronium and impeding the nitration.
- Dreizin, Edward L.,Schoenitz, Mirko,Vasudevan, Ashvin Kumar
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Read Online
- Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
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Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.
- Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
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p. 25841 - 25847
(2021/08/09)
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3O4 Nanoparticles
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This work reports the synthesis and catalytic application of mesoporous Au-loaded Mn3O4 nanoparticle assemblies (MNAs) with different Au contents, i. e., 0.2, 0.5 and 1 wt %, towards the selective oxidation of anilines into the corresponding nitroarenes. Among common oxidants, as well as several supported gold nanoparticle platforms, Au/Mn3O4 MNAs containing 0.5 wt % Au with an average particle size of 3–4 nm show the best catalytic performance in the presence of tert-butyl hydroperoxide (TBHP) as a mild oxidant. In all cases, the corresponding nitroarenes were isolated in high to excellent yields (85–97 %) and selectivity (>98 %) from acetonitrile or greener solvents, such as ethyl acetate, after simple flash chromatography purification. The 0.5 % Au/Mn3O4 catalyst can be isolated and reused four times without a significant loss of its activity and can be applied successfully to a lab-scale reaction of p-toluidine (1 mmol) leading to the p-nitrotulene in 83 % yield. The presence of AuNPs on the Mn3O4 surface enhances the catalytic activity for the formation of the desired nitroarene. A reasonable mechanism was proposed including the plausible formation of two intermediates, the corresponding N-aryl hydroxylamine and the nitrosoarene.
- Armatas, Gerasimos S.,Daikopoulou, Vassiliki,Koutsouroubi, Eirini D.,Lykakis, Ioannis N.,Skliri, Euaggelia
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- The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
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Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
- Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
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supporting information
p. 5680 - 5686
(2021/08/16)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- Transition metal catalyzed nitro-aromatic denitration method
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The invention provides a transition metal catalyzed nitro-aromatic denitration method, which comprises the following steps: in a nitrogen atmosphere, taking nitro-aromatic as a substrate in an organicsolvent, reacting under the action of alkali and a reducing agent under the action of a transition metal catalyst and a ligand, and carrying out column chromatography separation to obtain an aromaticcompound. The method can directly convert nitro aromatic hydrocarbon into corresponding aromatic hydrocarbon compounds, is high in catalytic efficiency, low in cost and convenient to operate, and canbe compatible with various functional groups. In addition, the directional reduction nitro group, position and number of the nitro group of the polynitro compound are regulated and controlled throughthe proportion and addition amount of the reducing agent and the catalytic system, so that the directional conversion of the polynitro group is realized.
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Paragraph 0027; 0029-0032; 0061-0064
(2020/08/18)
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- Methane Generation and Reductive Debromination of Benzylic Position by Reconstituted Myoglobin Containing Nickel Tetradehydrocorrin as a Model of Methyl-coenzyme M Reductase
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Methyl-coenzyme M reductase (MCR), which contains the nickel hydrocorphinoid cofactor F430, is responsible for biological methane generation under anaerobic conditions via a reaction mechanism which has not been completely elucidated. In this work, myoglobin reconstituted with an artificial cofactor, nickel(I) tetradehydrocorrin (NiI(TDHC)), is used as a protein-based functional model for MCR. The reconstituted protein, rMb(NiI(TDHC)), is found to react with methyl donors such as methyl p-toluenesulfonate and trimethylsulfonium iodide with methane evolution observed in aqueous media containing dithionite. Moreover, rMb(NiI(TDHC)) is found to convert benzyl bromide derivatives to reductively debrominated products without homocoupling products. The reactivity increases in the order of primary > secondary > tertiary benzylic carbons, indicating steric effects on the reaction of the nickel center with the benzylic carbon in the initial step. In addition, Hammett plots using a series of para-substituted benzyl bromides exhibit enhancement of the reactivity with introduction of electron-withdrawing substituents, as shown by the positive slope against polar substituent constants. These results suggest a nucleophilic SN2-type reaction of the Ni(I) species with the benzylic carbon to provide an organonickel species as an intermediate. The reaction in D2O buffer at pD 7.0 causes a complete isotope shift of the product by +1 mass unit, supporting our proposal that protonation of the organonickel intermediate occurs during product formation. Although the turnover numbers are limited due to inactivation of the cofactor by side reactions, the present findings will contribute to elucidating the reaction mechanism of MCR-catalyzed methane generation from activated methyl sources and dehalogenation.
- Hayashi, Takashi,Miyazaki, Yuta,Oohora, Koji
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supporting information
p. 11995 - 12004
(2020/09/15)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- Efficient heterogeneous palladium-catalyzed transfer hydrogenolysis of benzylic alcohols by formic acid
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An efficient heterogeneous palladium-catalyzed transfer hydrogenolysis- of primary, secondary, and tertiary benzylic alcohols using formic acid as hydrogen source has been developed. The resulting hydrocarbon products were obtained in excellent yields. Moreover, the system exhibits high chemoselectivity, reacting only with the hydroxy groups in the presence of other functional groups, and excellent re-cyclability.
- Afewerki, Samson,Córdova, Armando,Palo-Nieto, Carlos
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supporting information
p. 2330 - 2336
(2020/08/19)
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- NITRATION
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The present invention relates to a process for preparing a nitrated compound, comprising the step of reacting a compound (A) comprising at least one substituted or unsubstituted aromatic or heteroaromatic ring, wherein said heteroaromatic ring comprises at least one heteroatom selected from the group consisting of oxygen, sulfur, phosphor, selenium and nitrogen, with a compound of formula (I) wherein Y is selected from the group consisting of hydrogen and nitro.
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Page/Page column 36; 41; 46; 64; 37; 47; 42; 65
(2020/05/28)
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- Phosphonic acid mediated practical dehalogenation and benzylation with benzyl halides
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For the first time, by using H3PO3/I2 system, various benzyl chlorides, bromides and iodides were dehalogenated successfully. In the presence of H3PO3, benzyl halides underwent electrophilic substitution reactions with electron-rich arenes, leading to a broad range of diarylmethanes in good yields. These transformations feature green, cheap reducing reagents and metal-free conditions. A possible mechanism was proposed.
- Gao, Jing,Han, Li-Biao,Ma, Yonghao,Tang, Zilong,Wu, Xiaofang,Xiao, Jing
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p. 22343 - 22347
(2019/07/31)
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- Size-selective mesoporous silica-based Pt(II)complex as efficient and reusable photocatalytic material
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The grafting of a Pt(II)photocatalyst into three different mesoporous silica-based materials with different particle sizes and pore sizes was easily achieved through an amide bond formation. The analysis and results of the different characterization techniques showed that the catalyst is immobilized inside the pores of the materials and the photophysical properties of the catalyst are preserved after the covalent anchoring. The photocatalytic material catalyzed efficiently the debromination reaction of different substrates and is reused without detriment in its catalytic activity. In addition, the incorporation of the catalyst into mesoporous silica materials with different pore size allows the selective debromination of substrates by size discrimination.
- González-Mu?oz, Daniel,Casado-Sánchez, Antonio,del Hierro, Isabel,Gómez-Ruiz, Santiago,Cabrera, Silvia,Alemán, José
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p. 374 - 383
(2019/05/01)
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- Hydrophobic WO3/SiO2 catalyst for the nitration of aromatics in liquid phase
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WO3/SiO2 solid acid catalyst synthesized using sol gel method has shown promising activity (up to 65% conversion) for aromatic nitration in liquid phase using commercial nitric acid (70%) as nitrating agent without using any sulfuric acid. The water formed during the reaction as well as water from dilute nitric acid (70%) was removed azeotropically, however due to the hydrophilic nature of the catalyst, some water gets strongly adsorbed on catalyst surface forming a barrier layer between catalyst and organics. This prevents effective adsorption of substrate on catalyst surface for its subsequent reaction. To improve the activity further, the hydrophilic/hydrophobic nature of the catalyst was altered by post modification by grafting with commercial short chain organosilane (Dynasylan 9896). The modified 20% WO3/SiO2 catalyst when used for o-xylene nitration in liquid phase, showed significant increase in the conversion from 65% to 80% under identical reaction conditions. Catalyst characterization revealed decrease in the surface area of 20% WO3/SiO2 from 356 m2/g to 302 m2/g after grafting with Dynasylan 9896. The fine dispersion of WO3 particles (2–5 nm) on silica support was not affected due to modification. NMR and FTIR study revealed the decrease in surface hydroxyl groups imparting hydrophobicity to the catalyst. Interestingly the total acidic sites of the catalyst remained almost unaltered (0.54 mmol NH3/g) even after modification. Even though, the acidity and other characteristics of the catalyst did not change appreciably, there was a considerable increase in the o-xylene conversion which can be ascribed to the hydrophobic nature of the catalyst.
- Kulal,Kasabe,Jadhav,Dongare,Umbarkar
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p. 105 - 113
(2019/02/15)
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- 2-Methyl-1,3-disulfoimidazolium polyoxometalate hybrid catalytic systems as equivalent safer alternatives to concentrated sulfuric acid in nitration of aromatic compounds
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Ionic liquid-derived polyoxometalate salts [mdsim]3[PM12O40] (where M?=?W and Mo) of two heteropolyacids H3PW12O40.nH2O and H3PMo12O40.nH2O were synthesized using 2-methyl-1,3-disulfoimidazolium chloride ([mdsim][Cl]) ionic liquid and the corresponding heteropolyacids. Three equivalents of [mdsim][Cl] were treated with the respective Keggin-structured heteropolyacids (one equivalent) in aqueous medium at room temperature to afford the water-stable ionic polyoxometalates as acidic solids. They were completely characterized using spectroscopic and other analytical techniques including thermal analysis and Hammett acidity studies. The inherent Br?nsted acidic properties of ─SO3H group of these polyoxometalate salts were studied for the nitration of aromatic compounds with 69% HNO3 at normal temperature and 80°C without use of any external concentrated sulfuric acid. These strongly acidic polyoxometalates display good recyclability and efficient reusability.
- Saikia, Susmita,Borah, Ruli
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- Method for preparing paranitrotoluene by green nitration of methylbenzene
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The invention discloses a method for preparing paranitrotoluene by green nitration of methylbenzene. The method comprises the following steps: mixing the methylbenzene with a prepared MgO-Al2O3-CeO2-TiO2 composite oxide, heating to the temperature of 50-60 DEG C, stirring and mixing for 6-8 h, and carrying out ultrasonic dispersion for 1-2 h to obtain a mixture; and separately adding the preparedmixture and nitric acid in a micro-channel reactor, after carrying out nitration reaction in the micro-channel reactor, enabling the solution to flow out from the outlet, then standing for 24 h, filtering liquid of the lower layer, and washing, neutralizing and drying filtrate to obtain nitrate of the methylbenzene. The method is environmentally friendly, a large amount of waste acids cannot be generated, reaction selectivity is high, and the prepared paranitrotoluene has high purity and high yield.
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Page/Page column 5-7
(2019/03/24)
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- On/Off O2 Switchable Photocatalytic Oxidative and Protodecarboxylation of Carboxylic Acids
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Photoredox catalysis in recent years has manifested a powerful branch of science in organic synthesis. Although merging photoredox and metal catalysts has been a widely used method, switchable heterogeneous photoredox catalysis has rarely been considered. Herein, we open a new window to use a switchable heterogeneous photoredox catalyst which could be turned on/off by changing a simple stimulus (O2) for two opponent reactions, namely, oxidative and protodecarboxylation. Using this strategy, we demonstrate that Au@ZnO core-shell nanoparticles could be used as a switchable photocatalyst which has good catalytic activity to absorb visible light due to the localized surface plasmon resonance effect of gold, can decarboxylate a wide range of aromatic and aliphatic carboxylic acids, have multiple reusability, and are a reasonable candidate for synthesizing both aldehydes/ketones and alkane/arenes in a large-scale set up. Some biologically active molecules are also shown via examples of the direct oxidative and protodecarboxylation which widely provided pharmaceutical agents.
- Bazyar, Zahra,Hosseini-Sarvari, Mona
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p. 13503 - 13515
(2019/10/11)
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- A convenient room temperature ipso-nitration of arylboronic acid catalysed by molecular iodine using zirconium oxynitrate as nitrating species: An experimental and theoretical investigation
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A simple and convenient protocol has been developed for ipso-nitration of arylboronic acid catalysed by molecular iodine at room temperature, using zirconium oxynitrate as the nitrating species. The protocol is applicable to electronically diverse aryl- and heteroarylboronic acid moieties under mild reaction conditions with good to excellent isolated yields. Furthermore, a theoretical investigation has been performed for the same reaction, and reaction profiles are modelled using modern density functional theory (DFT). DFT-based results support the experimentally observed results.
- Mahanta, Abhijit,Gour, Nanda Kishor,Sarma, Plaban Jyoti,Borah, Raju Kumar,Raul, Prasanta Kumar,Deka, Ramesh Chandra,Thakur, Ashim Jyoti,Bora, Utpal
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- Preparation method of substituted nitrobenzene compound
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The invention discloses a preparation method of a substituted nitrobenzene compound. The method comprises the following steps: carrying out a decarboxylation reaction as shown below on a compound II under the action of alkali in a solvent at the temperature of 150 to 250 DEG C to obtain a compound I; the alkali is one or more of carbonates and bicarbonates of alkali metals. Compared with some metal-catalyzed decarboxylation methods, the preparation method of the substituted nitrobenzene compound has the advantages of simple operation, low production cost, convenient post-treatment and high yield, and more application values in industrial production.
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Paragraph 0030-0041
(2019/03/29)
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- Method and device for preparing methylnitro-benzene by channelization
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The invention discloses a method and a device for preparing methylnitro-benzene by channelization. The device comprises a storage tank, a nitrogen dioxide cylinder, an ozone generator, a flow pump, agas flowmeter, a reaction pipeline filled with a catalyst, a mixing pipeline, two T-shaped mixed joints, a cooling system, a heating system, a back pressure valve and a receiving tank. The method specifically comprises the following steps: opening the cooling system and the heating system; opening the ozone generator; arranging the flow pump and the gas flowmeter; and mixing raw materials liquid methyl benzene and nitrogen dioxide through the first T-shaped mixing joint and feeding the mixture into the mixing pipeline, then mixing the mixture with ozone in the second T-shaped mixing joint, feeding the mixture into the reaction pipeline filled with the catalyst for a nitrifying reaction, and post-treating a reaction liquid to obtain methylnitro-benzene. The method is controlled precisely and automatically, and is simple to operate, mild in reaction condition, simple in post treatment, quick to transfer mass and heat, high in safety and good in economical benefit.
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Paragraph 0043; 0044; 0045; 0046
(2019/02/04)
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- Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides
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A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also successfully carried out with this metal-free catalytic system in good to excellent yields.
- Gupta, Sampa,Ansari, Alisha,Sashidhara, Koneni V.
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supporting information
(2019/09/07)
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- Perylene-Grafted Silicas: Mechanistic Study and Applications in Heterogeneous Photoredox Catalysis
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A mechanistic study is herein presented for the use of heterogeneous photocatalysts based on perylene moieties. First, the successful immobilization of perylene diimides (PDI) on silica matrices is demonstrated, including their full characterization by means of electronic microscopy, surface area measurements, powder XRD, thermogravimetric analysis, and FTIR, 29Si and 13C solid-state NMR, fluorescence, and diffuse reflectance spectroscopies. Then, the photoredox activity of the material was tested by using two model reactions, alkene oxidation and 4-nitrobenzylbromide reduction, and mechanistic studies were performed. The mechanistic insights into their photoredox activity show they have promising dual photocatalytic activity for both organic oxidations and reductions.
- Carrillo, Adela I.,Elhage, Ayda,Marin, M. Luisa,Lanterna, Anabel E.
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supporting information
p. 14928 - 14934
(2019/12/02)
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- Selective reduction of nitro group in aryl halides catalyzed by silver nanoparticles modified with β-CD
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In this paper, we first report the selective reduction of nitro group in aryl halides catalyzed by silver nanoparticles modified with β-CD. Taking advantage of hydrophobic lumen and donor-acceptor behavior of β-CD, the halogenated alkyl groups on the aromatic ring can be enveloped in the inner cavity that thereby inhibits the reduction of the halogen. For validating the mechanism proposed by us, different silver nanoparticles were applied in parallel experiments. In our experiments, UV-vis spectra and NMR spectra were used to characterize the selectivity. This strategy represents an outstanding improvement on the synthesis of halogenated aromatic amines in comparison with the traditional route, and greatly expands the application of silver nanoparticles in catalytic field.
- Ding, Xu,Zhu, Geng,Guan, Jian-Ning,Han, Guo-Zhi
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p. 8201 - 8206
(2018/09/21)
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- Silica-supported perchloric acid and potassium bisulfate as reusable green catalysts for nitration of aromatics under solvent-free microwave conditions
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Silica-supported perchloric acid and bisulfate (SiO2/HClO4 and SiO2/KHSO4) have been developed as reusable green catalysts for nitration of aromatic compounds using NaNO2 in acetonitrile medium under conventional and solvent-free microwave conditions. The reaction times under microwave irradiation are significantly shorter than conventional method even though the yields obtained in microwave-assisted reactions are comparable with those obtained under reflux conditions.
- Kumar, M. Satish,Sriram, Y. Hemanth,Venkateswarlu,Rajanna,Sudhakar, M. Sai,Venkanna, Purugula,Saiprakash
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supporting information
p. 59 - 67
(2017/12/26)
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- Aerobic oxidations with N-hydroxyphthalimide in trifluoroacetic acid
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The potential of highly polar trifluoroacetic acid as a media for the metal-free aerobic oxidations propagated by phthalimide N-oxyl- (PINO) radical was demonstrated experimentally utilizing N-hydroxyphthalimide (NHPI) as a catalyst and HNO3 or NaNO2 as promoters. The oxidations of toluene, cyclohexane, adamantane, diamantane, and 3-oxadiamantane gave, respectively, benzaldehyde, adipic acid, 1-hydroxyadamantane, 1-hydroxydiamantane, and 9-hydroxy-3-oxadiamantane with up to 90% selectivities under high conversions of starting material. From the density functional theory computations at the M06-2X and B3LYP-D3 levels the polarized transition structures (TS) for the hydrogen abstraction from toluene and benzyl alcohol with highly electrophilic PINO-radical are substantially stabilized by non-covalent interactions (π–π stacking). Such additional stabilization is not present in the TS for the H-abstraction from benzaldehyde thus retarding its over-oxidation to benzoic acid.
- Gunchenko, Pavel A.,Li, Jing,Liu, Bifu,Chen, Hongyan,Pashenko, Alexander E.,Bakhonsky, Vladyslav V.,Zhuk, Tatyana S.,Fokin, Andrey A.
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- Method for nitrating aromatic compound by using nitrate under the action of auxiliary agent
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The invention discloses a method for nitrating an aromatic compound by using a nitrate under the action of an auxiliary agent, and provides an aromatic nitro compound preparation method, which comprises: in the presence of an external action and an auxiliary agent, carrying out a nitrating reaction on an aromatic compound and a metal nitrate or a hydrate thereof to obtain the aromatic nitro compound, wherein the external action can cause the physical and/or chemical property change of a substance, the auxiliary agent is a substance having water absorbing ability, the external action can be mechanical force or heating, and the mechanical force can be any one selected from compression, shearing, impacting, friction, stretching, bending and vibration. According to the present invention, the method does not require any solvents so as to avoid the generation of the waste liquid; the acidic substance is not used, such that the treatment is simple after the reaction is completed, and the equipment is not damaged; the added auxiliary agent can be theoretically recycled; and the method has extremely high conversion rate and extremely high selectivity, and can be used for the nitration of conventional aromatic compounds.
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Paragraph 0071; 0072; 0090; 0091
(2018/09/11)
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- Mechanical force under the action of the nitration of aromatic compounds of nitrate method (by machine translation)
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The invention discloses a mechanical force under the action of the nitration of aromatic compounds of nitrate method. The invention provides a method for preparing aromatic nitro compounds, comprising the following steps: under the action of mechanical force, aromatic compound with a metal nitrate or its hydrate by the nitration reaction, to obtain the aromatic nitro compound; the mechanical fastener is machinery offers can cause material physical and/or chemical nature of the change of the external force. The mechanical force can be compression, shear, impact, friction, tensile, bending and vibration of any kind. The invention has the following advantages: without the use of any solvent, thereby avoiding the waste liquid produced; and without the use of the acidic substance, the reaction is complete after treatment is simple, without any damage to the apparatus; a very high conversion and selectivity, can be applied to the nitration of conventional aromatic compound. (by machine translation)
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Paragraph 0056; 0057; 0085; 0086
(2018/09/11)
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- Fluoropolymer-Coated PDMS Microfluidic Devices for Application in Organic Synthesis
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In recent years there has been huge interest in the development of microfluidic reactors for the synthesis of small molecules and nanomaterials. Such reaction platforms represent a powerful and versatile alternative to traditional formats since they allow for the precise, controlled, and flexible management of reactive processes. To date, the majority of microfluidic reactors used in small-molecule synthesis have been manufactured using conventional lithographic techniques from materials such as glasses, ceramics, stainless steel, and silicon. Surprisingly, the fabrication of microfluidic devices from such rigid materials remains ill-defined, complex, and expensive. Accordingly, the microfluidic toolkit for chemical synthesis would significantly benefit from the development of solvent-resistant microfluidic devices that can be manufactured using soft-lithographic prototyping methods. Whilst significant advances in the development of solvent-resistant polymers have been made, only modest steps have been taken towards simplifying their use as microfluidic reactors. Herein, we emphasize the benefits of using a commercially available, amorphous perfluorinated polymer, CYTOP, as a coating with which to transform PDMS into a chemically inert material for use in organic synthesis applications. Its efficacy is demonstrated through the subsequent performance of photooxidation reactions and reactions under extremely acidic or basic conditions.
- Yang, Tianjin,Choo, Jaebum,Stavrakis, Stavros,de Mello, Andrew
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p. 12078 - 12083
(2018/08/21)
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- Synthesis of nitroolefins and nitroarenes under mild conditions
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1,3-Disulfonic acid imidazolium nitrate {[Dsim]NO3} was prepared and characterized as a new ionic liquid and nitrating agent for the ipso-nitration of various arylboronic acids and nitro-Hunsdiecker reaction of different α,β-unsaturated acids and benzoic acid derivatives, by in situ generation of NO2 to give various nitroarenes and nitroolefins without using any cocatalysts and solvents under mild conditions.
- Zarei, Mahmoud,Noroozizadeh, Ehsan,Moosavi-Zare, Ahmad R.,Zolfigol, Mohammad A.
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p. 3645 - 3650
(2018/04/14)
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- Ipso-nitration of arylboronic acids with copper nitrate and trifluoroace-tic acid
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An efficient and novel nitrating reagent has been developed for ipso-nitration of arylboronic acids. By using inexpensive and commercially available Cu(NO3)2/CF3COOH as nitrating reagent, various nitroarenes are produced in moderate to excellent yields (51-96%). Advantages of this procedure are the operational simplicity and no need of extra catalyst.
- Wang, Zhu-Qing,Guo, Meng-Ping,Wen, Yong-Ju,Shen, Xiu-Li,Lv, Mei-Yun,Zhou, Xiu-Ling
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p. 891 - 894
(2018/11/06)
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- Oxidation of Aniline to Nitrobenzene Catalysed by 1-Butyl-3-methyl imidazolium phosphotungstate Hybrid Material Using m-chloroperbenzoic Acid as an Oxidant
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Abstract: Keggin ion based hybrid materials, [BmIm]3[PW12O40], [TBA]3PW12O40 and [BuPy]3PW12O40, were prepared by proton exchange with organic cations, 1-butyl-3-methyl imidazolium ion, tetrabutylammonium ion and butylpyridinium ion, respectively. The formation of hybrid materials was confirmed by FTIR, PXRD, SEM, TG-DTA, DSC analysis. These hybrid compounds are active for oxidation of aniline using m-chloroperbenzoic acid as an oxidant. Among the three hybrid compounds, 1-butyl-3-methyl imidazolium phosphotungstate was found to be the best and efficient catalyst for selective aniline oxidation to nitrobenzene. It is a recoverable and reusable catalytic system. The redox property of the phosphotungstate cluster in the hybrid material is involved in the catalytic activity. Graphical Abstract: [Figure not available: see fulltext.].
- Meenakshi,Shakeela,Kutti Rani,Ranga Rao
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p. 246 - 257
(2017/10/23)
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- Glass wool: a novel support for heterogeneous catalysis
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Heterogeneous catalysis presents significant advantages over homogeneous catalysis such as ease of separation and reuse of the catalyst. Here we show that a very inexpensive, manageable and widely available material-glass wool-can act as a catalyst support for a number of different reactions. Different metal and metal oxide nanoparticles, based on Pd, Co, Cu, Au and Ru, were deposited on glass wool and used as heterogeneous catalysts for a variety of thermal and photochemical organic reactions including reductive de-halogenation of aryl halides, reduction of nitrobenzene, Csp3-Csp3 couplings, N-C heterocycloadditions (click chemistry) and Csp-Csp2 couplings (Sonogashira couplings). The use of glass wool as a catalyst support for important organic reactions, particularly C-C couplings, opens the opportunity to develop economical heterogeneous catalysts with excellent potential for flow photo-chemistry application.
- Elhage, Ayda,Wang, Bowen,Marina, Nancy,Marin, M. Luisa,Cruz, Menandro,Lanterna, Anabel E.,Scaiano, Juan C.
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p. 6844 - 6852
(2018/09/11)
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- Direct Catalytic Enantioselective Benzylation from Aryl Acetic Acids
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We demonstrate that metal-catalyzed enantioselective benzylation reactions of allylic electrophiles can occur directly from aryl acetic acids. The reaction proceeds via a pathway in which decarboxylation is the terminal event, occurring after stereoselective carbon-carbon bond formation. This mechanistic feature enables enantioselective benzylation without the generation of a highly basic nucleophile. Thus, the process has broad functional group compatibility that would not be possible employing established protocols.
- Moon, Patrick J.,Wei, Zhongyu,Lundgren, Rylan J.
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supporting information
p. 17418 - 17422
(2019/01/04)
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- Highly efficient protocol for the aromatic compounds nitration catalyzed by magnetically recyclable core/shell nanocomposite
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An efficient protocol for the nitration of aromatic compounds in the presence of a catalytic amount of sulfuric acid-functionalized silica-based magnetic core/shell nanocomposite was reported. The designed products were obtained in high yields in relatively short reaction times at room temperature under solvent-free conditions. The nanocatalyst was simply recovered from the reaction mixture by using an external magnet and efficiently reused for several times. The characterization of particle size, morphology and elemental analysis of the nanocatalyst were provided by scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses, respectively.
- Maleki, Ali,Aghaei, Morteza,Paydar, Reza
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p. 485 - 490
(2017/01/10)
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- Convenient, metal-free ipso-nitration of arylboronic acids using nitric acid and trifluoroacetic acid
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A feasible protocol for the direct ipso-nitration of arylboronic acids using trifluoroacetic acid and nitric acid as nitration reagent has been developed. Various aromatic nitro compounds are produced in moderate to good yields under the metal-free conditions. The method is operationally simple and regioselective, and might have potential application in industry.
- Shen, Guodong,Zhao, Lingyu,Liu, Wanxing,Huang, Xianqiang,Song, Huina,Zhang, Tongxin
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supporting information
p. 10 - 14
(2016/12/30)
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- Sulfated SO4 2?/WO3 as an efficient and eco-friendly catalyst for solvent-free liquid phase nitration of toluene with NO2
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With the increase in environmental awareness, developing a highly efficient and environmentally benign nitration process has very important academic and applied industrial values in the synthesis of nitro-compounds. Towards this goal, we have developed an efficient and environmentally friendly approach for solvent-free liquid phase nitration of toluene by employing NO2 as a nitrating agent and sulfated SO4 2?/WO3 as a catalyst replacing traditional nitric acid–sulfuric acid under mild conditions. The results indicate that SO4 2?/WO3 as an effective and eco-friendly catalyst exhibits excellent catalytic activity and reusability for the nitration of toluene with NO2. In addition, the possible pathway for liquid phase nitration of toluene with NO2 over sulfated SO4 2?/WO3 catalyst was suggested. The present method makes this nitration process safe and environmentally friendly, and has the potential to enable a sustainable production of nitro-compounds from the liquid phase nitration of aromatic hydrocarbon with NO2 in industrial applications.
- Jiao, Yinchun,Zhu, Man,Deng, Renjie,Jian, Jian,Yin, Yi,You, Kuiyi
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p. 3961 - 3974
(2017/06/20)
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- NH4I/tert-butyl hydroperoxide-promoted oxidative C–N cleavage of tertiary amines leading to nitroaromatic compounds
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A NH4I/tert-butyl hydroperoxide-promoted oxidation of tertiary N-aryl-N,N-dialkylamines in DMSO has been developed to access nitroaromatic compounds. This methodology involves sequential N-dealkylation reactions in one-pot and a radical pathway is proposed.
- Shao, Ying,Zheng, Hao,Wu, Zhuhong,Huang, Lei,Tong, Jingjing,Wu, Ming,Sun, Xiaoqiang
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p. 504 - 508
(2017/10/03)
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- Full Cleavage of C≡C Bond in Electron-Deficient Alkynes via Reaction with Ethylenediamine
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Reaction of 1,2-diaminioethane (ethylenediamine) with electron-deficient alkynes leads to full scission of the C≡C bond even in the absence of a keto group directly attached to the alkyne. This process involves oxidation of one of the alkyne carbons into C2 of a 2-R-4,5-dihydroimidazole with the concomitant reduction of the other carbon to a methyl group. The sequence of Sonogashira coupling with the ethylenediamine-mediated fragmentation described in this work can be used for selective formal substitution of halogen in aryl halides by a methyl group or a 4,5-dihydroimidazol-2-yl moiety.
- Vasilevsky, Sergei F.,Davydova, Maria P.,Mamatyuk, Victor I.,Tsvetkov, Nikolay,Hughes, Audrey,Baranov, Denis S.,Alabugin, Igor V.
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p. 421 - 429
(2017/04/07)
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- Highly Stable and Recyclable Graphene Layers Protected Nickel–Cobalt Bimetallic Nanoparticles as Tunable Hydrotreating Catalysts for Phenylpropane Linkages in Lignin
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Abstract: Nickel–cobalt bimetallic nanoparticles coated with several layers of graphene were developed through direct heating treatment of bimetallic oxide precursor prepared by the modified Pechini-type sol–gel method. These nanomaterials were demonstrated to be versatile catalysts for lignin depolymerization. The catalysts showed unexpectedly tunable selectivity that directly depends on the composition of bimetallic nanoparticles. Dimeric lignin model compounds can be converted totally and the hydrogenolysis selectivities above 85% over Ni–Co@C (Ni:Co = 1:3). During the recycling test, the nanocatalyst showed excellent recyclability in the ten-batch investigation. The deposition of graphene layers over bimetal nanoparticles fosters a subtle balance between protecting effects and surface accessibility to catalytic reactions and significantly improves their stability to air and moisture. Ni–Co@C catalysts were readily separated from the liquid mixtures with high recycling ratio due to their magnetic properties. Graphical Abstract: [Figure not available: see fulltext.] Ni–Co bimetallic nanoparticles are coated with graphene layers. Graphene layers over the nanoparticles protect them from deactivation. Ni–Co@C shows tunable selectivity in the hydrogenolysis of dimeric lignin linkage. The non-precious metal catalyst showed excellent recyclability and can be reused ten times without significant loss of activity.
- Chen, Bingfeng,Li, Fengbo,Yuan, Guoqing
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p. 2877 - 2885
(2017/09/18)
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- Highly efficient reduction of carbonyls, azides, and benzyl halides by NaBH4 in water catalyzed by PANF-immobilized quaternary ammonium salts
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A series of polyacrylonitrile fiber-supported quaternary ammonium salts (PANF-QAS) were prepared and applied to the catalytic reduction of aldehydes, ketones, azides, and benzyl halides in water using NaBH4 as the reducing reagent in a highly efficient, economic, and environmentally benign way. The structure-activity relationships were investigated, which showed that the catalysts made up of quaternary ammonium salts with longer alkyl chains, larger cationic radii and better lipophilicity speed up the reduction reaction to afford the products in excellent yield. Moreover, the optimized catalyst can be applied to the reduction of 1-naphthaldehyde in a continuous flow process with outstanding reactivity and recyclability.
- Du, Jianguo,Xu, Gang,Lin, Huikun,Wang, Guangwei,Tao, Minli,Zhang, Wenqin
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supporting information
p. 2726 - 2735
(2016/05/24)
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- Regioselective mononitration of aromatic compounds with N2O5 by acidic ionic liquids via continuous flow microreactor
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We employed N2O5 as highly active nitrating reagents and a host of acidic ionic liquid as catalysts in these reactions which were conducted in a continuous flow microreactor. When we utilized PEG400-DAIL as catalysts, the conversion of toluene was increased to 95.5 % and the yield of mononitration product (o/p ratio reached 1.10) significantly improved to 99 %, meanwhile the reaction time was drastically shortened to 1/120 of the conventional reactor. Nitration in ionic liquids was surveyed using a host of aromatic substrates with similar reactivity. The ionic liquid recycling procedures had also been devised.
- Liu, Jianhua,Li, Bindong,Wang, Huan
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p. 513 - 516
(2016/01/20)
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- Nitration of arenes by 1-sulfopyridinium nitrate as an ionic liquid and reagent by in situ generation of NO2
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1-Sulfopyridinium nitrate was synthesized as a potent nitrating agent for the nitration of arenes without the need for any co-catalysts. A variety of nitro compounds were synthesized and fully characterized by IR, 1H NMR, 13C NMR, thermal gravimetric analysis (TGA), differential thermal gravimetry (DTG), CHN analysis and mass spectroscopy. Mechanistically, in situ generated nitrogen dioxide as a radical from the reagent is proposed for the presented nitration protocol.
- Moosavi-Zare, Ahmad Reza,Zolfigol, Mohammad Ali,Zarei, Mahmoud,Noroozizadeh, Ehsan,Beyzavi, M. Hassan
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p. 89572 - 89577
(2016/10/03)
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- One-Pot C?H Functionalization of Arenes by Diaryliodonium Salts
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A transition-metal-free, mild, and highly regioselective synthesis of nitroarenes from arenes has been developed. The products are obtained in a sequential one-pot reaction by nitration of iodine(III) reagents with two carbon ligands, which are formed in situ from iodine(I). This novel concept has been extended to formation of aryl azides, and constitutes an important step towards catalytic reactions with these hypervalent iodine reagents. An efficient nitration of isolated diaryliodonium salts has also been developed, and the mechanism is proposed to proceed by a [2,2] ligand coupling pathway.
- Reitti, Marcus,Villo, Piret,Olofsson, Berit
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p. 8928 - 8932
(2016/07/26)
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- Synthesis method of 2-chloro-6-bromo-p-nitrobenzoic acid
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The present invention discloses a synthesis method of 2-chloro-6-bromo-p-nitrobenzoic acid, and belongs to the field of chemical synthesis. The synthesis method comprises the following steps: firstly using toluene as a raw material to produce p-nitrotoluene; then adding hydrochloric acid and tin powder to obtain p-toluidine; stirring the p-toluidine, the tin powder, zeolite and acetic acid for reaction; adding acetic anhydride after the reaction to produce methylacetanilid; after the production, adding potassium permanganate solution and ethanol for boiling and filtering; adjusting the pH by using a sulfuric acid to obtain p-nitro-ethyl benzoate; heating the obtained p-nitro-ethyl benzoate solid until melting; introducing a chlorine gas to obtain 2,6-dichloro-ethyl p-nitrobenzoate, water, BaBrO3 and dibromomethane; brominating hydrogen with stirring; extracting an organic phase by distillation crystallization to obtain 2-chloro-6-bromo-p-nitro-ethyl benzoate; finally hydrolyzing to obtain the 2-chloro-6-bromo-p-nitrobenzoic acid.
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Paragraph 0006
(2016/12/16)
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- A simple protocol for Cu-catalyzed protodecarboxylation of (hetero)aromatic carboxylic acids
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A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials.
- Li, Zhaojie,Fu, Zhengjiang,Zhang, Haixia,Long, Jiao,Song, Yuanyuan,Cai, Hu
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supporting information
p. 3014 - 3018
(2016/05/09)
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- Calcium tungstate: A convenient recoverable catalyst for hydrogen peroxide oxidation
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Calcium tungstate was found to be an excellent catalyst for large scale "green" oxidations of organic substrates (amines, alkenes, alcohols, sulfides) with hydrogen peroxide. It displays the unusual dual characteristics of producing a soluble pertungstate species, allowing for homogeneous reaction conditions, but then precipitating, unchanged, at the end of the oxidation. These qualities allow for easy catalyst recovery and minimal waste stream generation for large scale application.
- Tressler, Caitlin M.,Stonehouse, Peter,Kyler, Keith S.
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supporting information
p. 4875 - 4878
(2016/10/06)
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- NITRATION OF AROMATIC COMPOUNDS
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The present invention provides a process for nitrating aromatic compounds without the need for a solid catalyst and/or any organic solvents and/or any other additives. A typical process includes combining or admixing a nitric acid and an anhydride compound under conditions sufficient to produce a reactive intermediate. The aromatic compound to be nitrated is then added to this reactive intermediate to produce a nitroaromatic compound. The nitroaromatic compound can be substituted with one or more, typically, one to three, and often one or two nitrate (-NO2) groups.
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Paragraph 0049; 0050
(2016/08/17)
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- N-methyl-2-chloropyridinium iodide/NaNO2/Wet SiO2: Neutral reagent system for the nitration of activated aromatic compounds under very mild conditions
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Mononitration of activated aromatic compounds using N-methyl-2-chloro-pyridinium iodide (Mukaiyama reagent)/NaNO2/wet SiO2 reagent system under neutral, very mild and environmentally safer reaction condition has been developed. Various structurally diverse aromatic rings are subjected in this condition and the corresponding nitro-aromatic compounds are prepared in moderately high yields.
- Azadi, Roya,Nazari-Far, Zahra
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p. 136 - 140
(2015/06/22)
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- Regioselective catalyzed nitration of toluene by zeolites
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The nitration of toluene with nitric acid and nitrogen dioxide as nitration agent was studied. The effect of zeolite catalysts was also discussed. By using zeolite as catalysis, the yield of nitro-toluene was improved with nitric acid as nitration agent. The conversion of toluene and yield of nitro-toluene were both greatly enhanced with nitrogen dioxide as nitration agent.
- Dong, Xiongzi,Peng, Xinhua
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p. 2341 - 2342
(2016/05/19)
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- Ultrasonically Assisted Rate Enhancements in Trichloroisocyanuric Acid/DMF/NaNO2 Triggered Nitration of Aromatic Compounds and Decarboxylative Nitration of α,β-Unsaturated Acids
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An efficient and safe method for nitration of aromatic compounds and decarboxylative nitration of α,β-unsaturated acids was developed using trichloroisocyanuric acid (TCICA)/dimethylformamide (DMF) in the presence of NaNO2. The reaction times of conventional protocol reduced from 8-10 h to 1.0-1.5 h (60-90 min) under sonication, even though the yields are comparable under both the conditions.
- Kumar, Mukka Satish,Rajanna, Kamatala Chinna,Venkateswarlu, Marri,Venkanna, Purugula,Saiprakash, Pondichery Kuppuswamy
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p. 2251 - 2258
(2015/09/22)
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