- Superactive iodination reagent on a base of iodine chloride and silver sulfate
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After reaction of ICl and Ag2SO4 in sulfuric acid and separation of resulting AgCl a stable solution is formed, containing very active forms of electrophilic iodine. This solution has a powerful iodination ability with respect to aromatic compounds. Deactivated arenes are iodinated easily and in mild conditions by action of this new reagent in generally good yields of the iodoarenes.
- Chaikovski, Vitold K.,Kharlova, Tatjana S.,Filimonov, Victor D.,Saryucheva, Tamara A.
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Read Online
- Acid-Catalyzed Nucleophilic Aromatic Photosubstitution. A Reconsideration of Protonation in Excited States of Nitrobenzenes
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3-Bromonitrobenzene is photosubstituted inefficiently but cleanly by chloride ion to give 3-chloronitrobenzene.The photosubstitution is catalyzed by hydronium ion; the limiting quantum yield of 0.021 at infinite +> and 3.0 M -> is only 2-fold higher than the quantum yield (0.011) of the uncatalyzed photosubstitution at 3.0 M ->.The limiting quantum yield at infinite chloride ion concentration with no added acid is also 0.021.That 2-propanol does not intervene on the photosubstitution pathway to cause photoreduction indicates that radical intermediates are not involved, and the absence of deuterium incorporation on the aromatic ring accompanying photosubstitution indicates that the catalysis does not involve formation of a dihydrobenzene intermediate.The reaction appears to be an example of the so-called mechanism and the catalysis to be a manifestation of protonation of the 3?,?* state, which is the higher energy triplet state in 3-bromonitrobenzene.
- Wubbels, Gene G.,Susens, Douglas P.,Cuoghlin, E. Bryan
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Read Online
- Green route for the chlorination of nitrobenzene
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A new green chlorination process of deactivated aromatics has been developed, being environmental-friendly and allowing the continuous chlorination of 1.7 kg nitrobenzene/kg catalyst per day. The triple novelty consists of using a non-conventional chlorination agent, the trichloroisocyanuric acid (TCCA, C3N3O3Cl3), along with solid acid catalysts (mainly zeolites) in a continuous flow reactor system. Different zeolites and solid acids have been tested in the chlorination of nitrobenzene, chosen as a model deactivated aromatic substrate. HUSY zeolite was found as the more promising catalyst for performing the chlorination of nitrobenzene, with good conversions (39-64%) at high selectivity toward monochlorinated products (90-99%). Finally, it is worthy to note that HUSY zeolite could be reused for at least five successive runs.
- Boltz, Marilyne,De Mattos, Márcio C.S.,Esteves, Pierre M.,Pale, Patrick,Louis, Benoit
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Read Online
- Preparation method of M-nitrochlorobenzene
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The invention discloses a preparation method of m-nitrochlorobenzene. The method comprises the step of preparing m-nitrochlorobenzene by taking chlorobenzene as a raw material and N-nitropyrazole and H2SO4 as nitrating agents. The method specifically comprises the following steps: adding 8ml of 98% sulfuric acid into a four-neck bottle, dropwise adding 0.012 mol of chlorobenzene into concentrated sulfuric acid under the conditions that the mechanical stirring speed is 300 to 400r/min and the temperature is 20 DEG C, heating in a water bath to 60 DEG C after the charging is completed, averagely dividing 0.024 mol of N-nitropyrazole into four parts, sequentially adding the four parts of N-nitropyrazole at the temperature, heating the reaction system in the charging process, adding materials again after the temperature is reduced to the initial temperature, keeping stirring after the materials are added, reacting at the constant temperature of 65 DEG C for 6 hours, pouring reaction liquid into a container filled with ice blocks while the reaction liquid is hot, and stirring to reduce the temperature of the solution to 5 DEG C to separate out light yellow substances.
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Paragraph 0014-0022
(2021/07/08)
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- Low-temperature and highly efficient liquid-phase catalytic nitration of chlorobenzene with NO2: Remarkably improving the para-selectivity in O2-Ac2O-Hβ composite system
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In this work, we developed a low-temperature and efficient approach for the highly selective preparation of valuable p-nitrochlorobenzene from the liquid-phase catalytic nitration of chlorobenzene with NO2 in O2-Ac2O-Hβ composite system. The results demonstrated that the introduction of molecular oxygen remarkably enhanced the chlorobenzene conversion and the cooperation catalysis of Hβ zeolite and Ac2O envidently improved the selectivity to para-nitro product. Under the optimized reaction conditions, 93.6 % of the selectivity to p-nitrochlorobenzene with 84.0 % of chlorobenzene conversion was obtained, and the ratio of p-nitrochlorobenzene to o-nitrochlorobenzene could reach up to 20.3. Furthermore, the selectivity distribution of nitration products was reasonably explained by the density functional theory (DFT) calculation. Finally, the possible nitration reaction pathway of chlorobenzene with NO2 was suggested in O2-Ac2O-Hβ composite catalytic system. The present work affords a new and mild nitration approach for highly selective preparation of valuable para-nitro products, and has potential industrial application prospects.
- Deng, Renjie,Liu, Pingle,Luo, He'an,Ni, Wenjin,You, Kuiyi,Zhao, Fangfang
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- Synthesis of thioethers, arenes and arylated benzoxazoles by transformation of the C(aryl)-C bond of aryl alcohols
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Transformation of aryl alcohols into high-value functionalized aromatic compounds by selective cleavage and functionalization of the C(aryl)-C(OH) bond is of crucial importance, but very challenging by far. Herein, for the first time, we report a novel and versatile strategy for activation and functionalization of C(aryl)-C(OH) bonds by the cooperation of oxygenation and decarboxylative functionalization. A diverse range of aryl alcohol substrates were employed as arylation reagents via the cleavage of C(aryl)-C(OH) bonds and effectively converted into corresponding thioether, arene, and arylated benzoxazole products in excellent yields, in a Cu based catalytic system using O2 as the oxidant. This study offers a new way for aryl alcohol conversion and potentially offers a new opportunity to produce high-value functionalized aromatics from renewable feedstocks such as lignin which features abundant C(aryl)-C(OH) bonds in its linkages.
- Chen, Bingfeng,Han, Buxing,Liu, Mingyang,Meng, Qinglei,Song, Jinliang,Zhang, Pei,Zhang, Zhanrong
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p. 7634 - 7640
(2020/08/14)
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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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- Dimethyl sulfoxide-accelerated reductive deamination of aromatic amines with t-BuONO in tetrahydrofuran
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An efficient method for the conversion of aryl amines into arenes by a one-pot reductive deamination has been achieved. It was found the reductive deamination using t-BuONO in tetrahydrofuran could be accelerated by dimethyl sulfoxide and provided the deamination products with good yields under mild conditions. A plausible mechanism is discussed.
- Fang, Lu,Qi, Liang,Ye, Longfei,Pan, Zhentao,Luo, Wenjun,Ling, Fei,Zhong, Weihui
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p. 579 - 583
(2018/11/27)
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- Method for preparing nitro compound by using graphene to catalyze carbon dioxide
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The invention discloses a method for preparing a nitro compound by using graphene to catalyze carbon dioxide. A graphene material is applied to catalysis of a reaction of carbon dioxide and a nitrification substrate such as an aromatic compound to prepare the nitro compound. The method is used for replacing a traditional nitric acid/sulfur acid method to prepare the nitro compound, so that the atom utilization rate of the reaction is increased, the energy is saved, and the emission is reduced; and the method has the characteristic of atom economy during industrial preparation of the nitro compound.
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Paragraph 0033-0034
(2018/06/16)
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- Method for preparing nitro compound by using graphene to catalyze nitric oxide
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The invention discloses a method for preparing a nitro compound by using graphene to catalyze nitric oxide. A graphene oxide carbon material is used for catalysis of a reaction of nitric oxide and a nitrification substrate such as an aromatic compound to prepare the nitro compound. The method is used for replacing a traditional nitric acid/sulfur acid method to prepare the nitro compound, so thatthe atom utilization rate of the reaction is increased, the energy is saved, and the emission is reduced; and the method has the characteristic of atom economy during industrial preparation of the nitro compound.
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Paragraph 0037; 0038
(2018/06/16)
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- A Predictive Model for the Decarboxylation of Silver Benzoate Complexes Relevant to Decarboxylative Coupling Reactions
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Decarboxylative coupling reactions offer an attractive route to generate functionalized arenes from simple and readily available carboxylic acid coupling partners, yet they are underutilized due to limitations in the scope of carboxylic acid coupling partner. Here we report that the field effect parameter (F) has a substantial influence on the rate of decarboxylation of well-defined silver benzoate complexes. This finding provides the opportunity to surpass current substrate limitations associated with decarboxylation and to enable widespread utilization of decarboxylative coupling reactions.
- Crovak, Robert A.,Hoover, Jessica M.
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p. 2434 - 2437
(2018/02/28)
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- A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids leading to chlorinated arenes
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A highly efficient heterogeneous copper-catalyzed chlorodeboronation of arylboronic acids with inexpensive N-chlorosuccinimide (NCS) was achieved in MeCN in the presence of 10 mol% of l-proline-functionalized MCM-41-immobilized copper(i) complex [MCM-41-l-proline-CuCl] under mild conditions, yielding a variety of aryl chlorides in excellent yields. This method proved to be tolerant of a broad range of functional groups and particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient without copper catalysis. This heterogeneous copper catalyst can be recovered by a simple filtration of the reaction solution and recycled for at least 10 times without any decreases in activity.
- He, Wen,Zhang, Rongli,Cai, Mingzhong
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p. 764 - 770
(2017/01/13)
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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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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
- -
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Paragraph 0058
(2018/01/03)
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- Conformations, equilibrium thermodynamics and rotational barriers of secondary thiobenzanilides
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The article deals with conformational behaviour of 2-methoxy-2′-hydroxythiobenzanilides. The CS-NH group of these compounds preferentially adopts the Z-conformation. Entropy favours the Z-conformer over the E-conformer, whereas enthalpy slightly favours the E-conformer over the Z-conformer. The rotational barrier about the CS-NH bond was determined to be (81.5±0.4) kJ/mol. No significant rotational barrier was found on the Ar-CS and Ar-NH bonds. All experimental outcomes are compared with the results of quantum-chemical calculations.
- Kozic, Ján,Novák, Zdeněk,?ímal, Václav,Profant, Václav,Kune?, Ji?í,Vin?ová, Jarmila
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p. 2072 - 2083
(2016/04/09)
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- Aerobic copper-catalyzed decarboxylative thiolation
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Copper-catalyzed decarboxylative thiolation using molecular oxygen as the sole oxidant was developed. A variety of aromatic carboxylic acids including 2-nitrobenzoic acids, pentafluorobenzoic acid and several heteroaromatic carboxylic acids undergo efficient thiolation to furnish the aryl sulfides in moderate to excellent yields.
- Li, Minghao,Hoover, Jessica M.
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supporting information
p. 8733 - 8736
(2016/07/15)
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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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- Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
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A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
- Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
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p. 10498 - 10504
(2015/11/18)
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- Poly(4-vinylpyridine)-nitrating mixture complex (PVP-NM): Solid nitrating mixture equivalent for safe and efficient aromatic nitration
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Friedel-Crafts type aromatic nitration has served as an indispensable reaction within both industrial and academic applications. However, growing concern over the use of copious amounts of strong acids has prompted the search for more environmentally friendly alternatives. Polymer-bound Bronsted acids, on the other hand, have been shown useful as convenient alternatives to liquid acids. Nitric acid and sulfuric acids have, therefore, been combined, both individually and as a mixture, with poly(4-vinylpyridine). The new solid acid systems have been used to nitrate both activated and deactivated arenes under mild conditions and proved to be effective nitrating agent.
- Surya Prakash,Gurung, Laxman,Glinton, Kevin E.,Belligund, Kavita,Mathew, Thomas,Olah, George A.
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supporting information
p. 3446 - 3451
(2015/06/25)
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- Steric-Hindrance-Induced Regio- and Chemoselective Oxidation of Aromatic Amines
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Unusual regio- and chemoselective oxidation of aromatic amines hindered with ortho substituents (except -NH2, -NHCH3, and -OH) to the corresponding nitro compounds is described by use of nonanebis(peroxoic acid). The mechanistic investigation for selective oxidation of amines ortho-substituted with -NH2 or -OH showed the involvement of H-bonding between the ortho hydrogen of the adjacent -XH group (where X = NH, NR, or O) and an oxygen atom from the diperoxy acid. Various mono- and diamines are oxidized into corresponding mononitro derivatives in high yield and purity without employing any protection strategies. The protocol was also found to successful on the gram scale.
- Patil, Vilas Venunath,Shankarling, Ganapati Subray
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p. 7876 - 7883
(2015/09/01)
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- MFI-type zeolite nanosheets for gas-phase aromatics chlorination: A strategy to overcome mass transfer limitations
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The continuous gas-solid (environmentally-friendly) chlorination of deactivated arenes using trichloroisocyanuric acid (TCCA, C3N 3O3Cl3) as a chlorination agent was chosen to compare the catalytic performances of various MFI-type catalysts in a reaction demanding a strong acidity. Mass transfer limitations were also evaluated by reacting either chloro- or nitrobenzene through a ZSM-5 zeolite porous network having different crystal sizes and morphologies. Whereas, the reaction rate was completely controlled by internal diffusion in 10-15 μm-sized big ZSM-5 zeolite crystals (Weisz modulus, big crystals ~ 10), the impact of internal diffusion could be ruled out for ZSM-5 nanocrystals (200-400 nm) and in stacked ZSM-5 nanosheets (thickness 2 nm). Based on reactivity differences in arene halogenation between the two nano-sized ZSM-5 zeolites, we were able to estimate the quantity of mild acidic silanol groups in ZSM-5 nanosheets to roughly 1/3 of the total amount of Brnsted acid sites.
- Boltz, Marilyne,Losch, Pit,Louis, Benoit,Rioland, Guillaume,Tzanis, Lydie,Daou, T. Jean
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p. 27242 - 27249
(2014/07/21)
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- Ipso-Nitrosation of arylboronic acids with chlorotrimethylsilane and sodium nitrite
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Nitroso compounds are versatile reagents in synthetic organic chemistry. Herein, we disclose a feasible protocol for the ipso-nitrosation of aryl boronic acids using chlorotrimethylsilane-sodium nitrite unison as nitrosation reagent system.
- Prakash, G.K. Surya,Gurung, Laxman,Schmid, Philipp Christoph,Wang, Fang,Thomas, Tisa Elizabeth,Panja, Chiradeep,Mathew, Thomas,Olah, George A.
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p. 1975 - 1978
(2014/04/03)
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- Regioselective mononitration of chlorobenzene using caprolactam-based Br?nsted acidic ionic liquids
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Three kinds of Br?nsted acidic ionic liquids caprolactam benzenesulfonate ([CP]BSA), caprolactam hydrosulfate ([CP]HSO4) and caprolactam p-toluenesulfonate ([CP]pTSA) were synthesized. The structures of the ILs were confirmed by 1HNM
- Zhang, Cun,Yu, Mei-Jing,Pan, Xiao-Yu,Wu, Guo,Jin, Liang,Gao, Wei-Dan,Du, Meng,Zhang, Jun-Chao
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p. 101 - 105
(2014/01/06)
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- Protodecarboxylation of carboxylic acids over heterogeneous silver catalysts
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A heterogeneous supported Ag catalyst for the protodecarboxylation of aromatic carboxylic acids has been developed. Control of the metal particle size proved extremely important. The highest activity was achieved with a silver loading of 10 wt%, which had relatively big metal crystallites of 40 nm. It is inferred that the adsorption of the aromatic moiety requires terrace sites rather than edges or corners at the metal nanoparticle. The amphoteric support, γ-Al2O3, gave the most active catalysts. Oxygen coverage of the surface is essential for catalytic activity. A mechanism has been proposed with the critical steps (1) formation of a benzoyl anion by reaction with a base in the reaction medium, (2) binding of the anionic species at the Ag+ surface sites with (3) extrusion of CO2 and (4) proton transfer from another molecule of carboxylic acid, followed by desorption of the decarboxylated species and binding of the benzoate to the active site to complete the catalytic cycle. With 2-nitrobenzoic acid as substrate, the catalyst had a turnover frequency (TOF) of 216 h-1. The catalyst showed good activity for benzoic acid with nitro, methoxy and halogen substituents at the ortho-position as well as for heteroaromatic carboxylic acids. The Royal Society of Chemistry.
- Toy, Xiu Yi,Roslan, Irwan Iskandar Bin,Chuah, Gaik Khuan,Jaenicke, Stephan
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p. 516 - 523
(2014/02/14)
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- Oxidation of aromatic amines into nitroarenes with m-CPBA
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A versatile and highly efficient approach for the synthesis of nitroarenes from aromatic amine using m-CPBA has been developed. This oxidation reaction was operationally straightforward and proceeded to afford products in good isolated yields.
- Liu, Jia,Li, Jue,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 1581 - 1584
(2014/03/21)
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- Efficient ipso-nitration of arylboronic acids with iron nitrate as the nitro source
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A novel, simple and efficient ipso-nitration of arylboronic acids with iron nitrate has been developed. The protocol uses readily available arylboronic acids as the starting materials, inexpensive iron nitrate (0.5 equiv.) as the nitro source without addition of an additive, and the corresponding nitroarenes were obtained in good to excellent yields.
- Jiang, Min,Yang, Haijun,Li, Yong,Jia, Zhiying,Fu, Hua
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p. 25602 - 25604
(2013/12/04)
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- Regioselective nitration of aromatics with nanomagnetic solid superacid SO42-/ZrO2-MxOy-Fe 3O4 and its theoretical studies
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A series of micro- and nanosulfated zirconia loaded on Fe3O 4 or other metal oxides (SO42-/ZrO 2-MxOy-Fe3O4 (M=Ti 4+, V5+, and Zn2+)) was prepared, characterized, and used in nitration. The nitration conditions with these solid superacids were then optimized to achieve the best regioselectivity and improve the performances of the catalysts as well. In the experimental results, SZTF (SO42-/ZrO2-TiO2-Fe 3O4) showed excellent catalytic activity and it increased the surface area of SO42-/ZrO2 by up to 15 %. The increase not only facilitated the generation of NO2+, but also provided more opportunities for metal ions to interact with aromatic compounds. With chlorobenzene as substrate, theoretical research on its geometric parameters, electron clouds, and electron spin density was used to investigate the interaction between transition metals and chlorobenzene.
- Wang, Peng Cheng,Zhu, Jie,Liu, Xiang,Lu, Ting Ting,Lu, Ming
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p. 310 - 317
(2013/08/23)
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- Electrophilic chlorination of arenes with trichloroisocyanuric acid over acid zeolites
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Trichloroisocyanuric acid (TCCA) reacts with arenes and its reactivity is highly affected by the acid strength of the reaction medium. Deactivated arenes are efficiently chlorinated by TCCA in solid acids. Our experimental results, along with DFT calculations show that chlorination using solid acid catalysis is feasible, thus leading to possible replacement of strong liquid acids used to promote this superelectrophilic reaction. We have tested several solid acids, showing the synergic need for acid strength and pore size for promoting the reaction.
- Mendon?a, Gabriela F.,Bastos, Alexander R.,Boltz, Marilyne,Louis, Beno?t,Pale, Patrick,Esteves, Pierre M.,De Mattos, Marcio C.S.
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- Halogen exchange via a halogenation of diaryliodonium salts with cuprous halide
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An efficient halogenation reaction has been developed with diaryliodonium salts and cuprous halides. Various diaryliodonium salts 1 could perform the reaction with readily available CuBr or CuCl in CH3CN at 80°C, assembling bromoarenes or chloroarenes in up to 92% yields. This provides us a method for the transformation from iodoarenes to other haloarenes.
- Li, Jian,Liu, Li,Ding, Dong,Sun, Jiang-Tao
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p. 541 - 548
(2014/01/06)
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- Copper-catalyzed decarboxylation of aromatic carboxylic acids: En route to milder reaction conditions
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The copper-catalyzed decarboxylation of carboxylic aromatic acids has been advantageously achieved by using aliphatic amines like tetramethylethylenediamine (TMEDA) or hexamethylenetetraamine (HMTA) as ligands instead of the aromatic heterocyclic amines (quinoline, phenanthroline) used until now. The improvement is significant since the reaction can be performed at a lower temperature (ca. 50 °C less) and the reaction time is clearly shorter (15 min instead of 12 to 24 h). Copyright
- Cahiez, Gerard,Moyeux, Alban,Gager, Olivier,Poizat, Mael
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supporting information
p. 790 - 796
(2013/04/10)
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- Recyclable nanoscale copper(I) catalysts in ionic liquid media for selective decarboxylative C-C bond cleavage
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Here we report the synthesis and application of finely divided Cu 2O nanoparticles (Cu2O-NPs) in the range from 5.5 nm to 8.0 nm in phosphonium ionic liquids as the first recyclable and effective catalytic system for smooth, ligand- and additive-free protodecarboxylation of 2-nitrobenzoic acid as a model substrate and further derivatives. The reactions run with low catalyst loadings and result in quantitative yield in ten consecutive recycling experiments. In addition this system is highly selective towards electron-poor 2-nitrobenzoic acids.
- Kessler, Michael T.,Gedig, Christian,Sahler, Sebastian,Wand, Patricia,Robke, Silas,Prechtl, Martin H. G.
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p. 992 - 1001
(2013/04/24)
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- Halogenation and DNA cleavage via thermally stable arenediazonium camphorsulfonate salts
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A series of stable arenediazonium camphorsulfonate salts (2a-2j) were synthesized by simple diazotization of several aromatic amines in the presence of sodium nitrite and camphorsulfonic acid. All the new arenediazonium camphorsulfonates, which were characterized by multinuclear (1H and 13C) NMR, IR, DSC, and X-ray diffraction analysis (2e and 2f) provide unambiguous proof for the molecular structures of 2e and 2f. The efficient application of these salts in halogenation reactions was studied in solvent and solvent-free conditions and the DNA cleavage activity was also assessed. These arenediazonium camphorsulfonate salts are noticed as efficient DNA cleaving agents.
- Vajpayee, Vaishali,Moon, Mi Eun,Lee, Sunmi,Ravikumar, Sambandam,Kim, Hyunuk,Ahn, Byungchan,Choi, Seoyoon,Hong, Soon Ho,Chi, Ki-Whan
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p. 3511 - 3517
(2013/04/23)
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- Copper-catalyzed conversion of aryl and heteroaryl bromides into the corresponding chlorides
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An efficient method for the synthesis of aryl and heteroaryl chlorides is described. The reactions of aryl and heteroaryl bromides with tetramethylammonium chloride proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding chlorides in satisfactory to excellent yields.
- Feng, Xiujuan,Qu, Yiping,Han, Yanlei,Yu, Xiaoqiang,Bao, Ming,Yamamoto, Yoshinori
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supporting information
p. 9468 - 9470
(2012/10/29)
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- General copper-catalyzed transformations of functional groups from arylboronic acids in water
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A simple and general copper-catalyzed method has been developed for transformations of various functional groups (i I, i N3, i SO2R, i OH, i NH2, and i NO 2) on aromatic rings from arylboronic acids in water under air. The protocol uses cheap and readily available inorganic salts (KI, NaN3, NaSO2R, NaOH, NaNO2) and aqueous ammonia as the functional-group sources, simple Cu2O/NH3 as the catalyst system, environmentally friendly water as the solvent, and oxygen in air as the oxidant. Importantly, the copper catalyst system in water was recyclable. This study should provide a useful strategy for interconversions of the functional groups on aromatic rings.
- Yang, Haijun,Li, Yong,Jiang, Min,Wang, Junmei,Fu, Hua
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experimental part
p. 5652 - 5660
(2011/06/23)
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- Trichloroisocyanuric acid in 98% sulfuric acid: A superelectrophilic medium for chlorination of deactivated arenes
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Trichloroisocyanuric acid (TCCA) reacts with arenes and its reactivity is highly affected by the acid strength of the reaction medium. Deactivated arenes are efficiently chlorinated by TCCA in H2SO4. Our results, along with DFT calculations and 13C NMR spectrometry suggest the formation of a monoprotonated TCCA superelectrophile as the reactive species that can efficiently transfer electrophilic Cl+ to even very weak nucleophiles, such as m-dinitrobenzene.
- Mendo?a, Gabriela Fonseca,Senra, M?nica Rufino,Esteves, Pierre M.,De Mattos, Marcio C.S.
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experimental part
p. 176 - 181
(2012/04/04)
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- Metal-free chlorodeboronation of organotrifluoroborates
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A mild and metal-free method for the chlorodeboronation of organotrifluoroborates using trichloroisocyanuric acid (TCICA) was developed. Aryl-, heteroaryl-, alkenyl-, alkynyl-, and alkyltrifluoroborates were converted into the corresponding chlorinated products in good yields. This method proved to be tolerant of a broad range of functional groups.
- Molander, Gary A.,Cavalcanti, Livia N.
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experimental part
p. 7195 - 7203
(2011/10/13)
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- Copper-catalyzed chlorination of functionalized arylboronic acids
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"Chemical Equation Presented" A mild, efficient, Cu(I)-catalyzed method for the conversion of arylboronic acids to aryl chlorides Is reported. This method is particularly useful for the conversion of electron-deficient arylboronic acids to aryl chlorides, a transformation that is inefficient In the absence of Cu catalysis.
- Wu, Hong,Hynes Jr., John
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supporting information; experimental part
p. 1192 - 1195
(2010/04/27)
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- Gold-catalysis: Reactions of organogold compounds with electrophiles
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Different arylgold(I), one alkynylgold(I), and one vinylgold(I) triphenylphosphane complexes were subjected to electrophilic halogenation reagents. With N-chlorosuccinimid, N-bromosuccinimid, and N-iodosuccinimid as well as the Barluenga reagent, selectively halogenated compounds were obtained. Trifluoroacetic acid, as a source of protons, leads to a clean protodeauration. With N-fluorobenzenesulfonimide or Selectfluor, exclusively a homocoupling was observed. For the precursor of the vinylgold(I) complex, a similar oxidative coupling could be induced by gold(III) chloride. Reactions with silicon or tin electrophiles failed. CSIRO 2010.
- Hashmi, A. Stephen K.,Ramamurthi, Tanuja Dondeti,Todd, Matthew H.,Tsang, Althea S.-K.,Graf, Katharina
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experimental part
p. 1619 - 1626
(2011/09/12)
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- Efficient and economic halogenation of aryl amines via arenediazonium tosylate salts
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Arenediazonium tosylate salts have been successfully employed as a new and efficient reagent in halogenation reactions. A novel and economic protocol has been developed for the bromination and chlorination of various anilines using arenediazonium tosylate salts. A wide variety of reaction conditions were studied in acetonitrile at either room temperature or 60 °C in the presence or absence of catalyst with good to excellent yields. A surprising result showed the formation of acetanilides as a major product of aniline and methyl-substituted aniline halogenations in high yields.
- Lee, Young Min,Moon, Mi Eun,Vajpayee, Vaishali,Filimonov, Victor D.,Chi, Ki-Whan
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experimental part
p. 7418 - 7422
(2010/10/01)
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- An expeditious and environmentally benign preparation of aryl halides from aryl amines by solvent-free grinding
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An efficient solvent-free methodology for conversion of various aryl amines into bromides and chlorides via arenediazonium tosylate salts under grinding conditions is disclosed. This new methodology not only avoids the use of strong acids and expensive reagents for diazotization-halogenation reactions, but also decreases the amount of organic waste from the reaction process.
- Moon, Mi Eun,Choi, Younghwa,Lee, Young Min,Vajpayee, Vaishali,Trusova, Marina,Filimonov, Victor D.,Chi, Ki-Whan
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scheme or table
p. 6769 - 6771
(2011/03/17)
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- Selective oxidation of aromatic amines to nitro derivatives using potassium iodide-tert-butyl hydroperoxide catalytic system
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The direct oxidation of aromatic primary amines to the corresponding nitro compounds selectively in 47-98% yields has been achieved by using potassium iodide as catalyst and tert-butyl hydroperoxide as the external oxidant. The present catalytic system works well for both electron-rich and electron-poor substrates.
- Reddy, K. Rajender,Maheswari, C. Uma,Venkateshwar,Kantam, M. Lakshmi
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supporting information; experimental part
p. 93 - 96
(2009/08/07)
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- Nitration of simple aromatics with NO2 under air atmosphere in the presence of novel Bronsted acidic ionic liquids
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Aromatics nitrate with NO2/air catalyzed by novel Bronsted acidic ionic liquids (ILs) without any volatile chlorinated organic solvent under mild conditions. The ILs employed were caprolactam based, [Caprolactam]X (X-=pTSO-, BSO-, BF4-, NO3-), which are o
- Qi, Xiufang,Cheng, Guangbin,Lu, Chunxu,Qian, Desheng
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p. 537 - 545
(2008/04/12)
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- Facile Synthesis of 2-Bromo-3-fluorobenzonitrile: An Application and Study of the Halodeboronation of Aryl Boronic Acids
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A scaleable synthesis of 2-bromo-3-fluorobenzonitrile via the NaOMe-catalyzed bromodeboronation of 2-cyano-6-fluorophenylboronic acid was developed. The generality of this transformation was demonstrated through the halodeboronation of a series of aryl boronic acids. Both aryl bromides and aryl chlorides were formed in good to excellent yields when the corresponding aryl boronic acid was treated with 1,3-dihalo-5,5-dimethylhydantoin and 5 mol % NaOMe.
- Szumigala Jr., Ronald H.,Devine, Paul N.,Gauthier Jr., Donald R.,Volante
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p. 566 - 569
(2007/10/03)
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- ipso-nitration of arylboronic acids with chlorotrimethylsilane-nitrate salts
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A mixture of nitrate salt and chlorotrimethylsilane is found to be an efficient regioselective nitrating agent for the ipso-nitration of arylboronic acids to produce the corresponding nitroarenes in moderate to excellent yields. High selectivity, simplicity, and convenience are the key features of the reaction.
- Surya Prakash,Panja, Chiradeep,Mathew, Thomas,Surampudi, Vijayalakshmi,Petasis, Nicos A.,Olah, George A.
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p. 2205 - 2207
(2007/10/03)
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- Ethyl acetate as a pro-reducing agent in an one-pot reductive deamination of nitroanilines
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The reductive deamination of various nitro-substituted anilines by the new method (20% H2SO4/NaNO2/ethyl acetate, Method 1) was studied and compared that with a similar procedure previously developed by Pare et al. (i.e., concentrated H2SO4/NaNO2/ethanol, Method 2) for the dediazonization of 4-methyl-2,6-dinitroaniline. The deaminated products derived from the mononitro-substituted anilines were obtained in good-to-high yield by Method 1 depending upon the position of the nitro group to the amino function. The higher yield of the de-aminated products was observed from the substituted meta-nitroanilines. Method 1 was more suitable for the deamination of 3-nitroanilines. Method 2 was more favorable for the de-amination of denitro-substituted anilines than that for the mononitroanilines. Ethyl acetate was more suitable for the reductive deamination of mononitroanilines, while ethanol was more appropriate for dinitroanilines.
- Bacherikov, Valeriy A.,Wang, May-Jane,Cheng, Shu-Yun,Chen, Ching-Huang,Chen, Kuo-Tung,Su, Tsann-Long
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p. 1027 - 1032
(2007/10/03)
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- Paradigm confirmed: The first use of ionic liquids to dramatically influence the outcome of chemical reactions
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It has been an unproven paradigm that the choice of which ionic liquid to use in a chemical reaction can have a dramatic effect on the outcome of that chemical reaction. We demonstrate, for the first time, that the reaction of toluene and nitric acid in three different ionic liquids gives rise to three completely different products in high yield. Furthermore, ionic liquids can catalyze these reactions with the only byproduct being water.
- Earle, Martyn J.,Katdare, Suhas P.,Seddon, Kenneth R.
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p. 707 - 710
(2007/10/03)
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- Nitration of aromatic compounds with nitric acid catalyzed by ionic liquids
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Nitration of simple aromatic compounds with 62% nitric acid is successfully carried out under solvent-free condition in a biphasic mode in the presence of the Bronsted acidic ionic liquids; the only by-product is water and ionic liquids are capable of being reused without any separation.
- Qiao, Kun,Yokoyama, Chiaki
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p. 808 - 809
(2007/10/03)
-
- N-halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
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N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. Because BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H0 ≈ 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF3-H2O has been developed. DFT calculations at the B3LYP/6-311++G**//B3LYP/6-31G* level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X+ from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X+ which would readily react with the aromatic substrates. Structural aspects of the BF 3-H2O complex have also been investigated.
- Prakash, G. K. Surya,Mathew, Thomas,Hoole, Dushyanthi,Esteves, Pierre M.,Wang, Qi,Rasul, Golam,Olah, George A.
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p. 15770 - 15776
(2007/10/03)
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- Halogenation of Aromatic Compounds by N-chloro-, N-bromo-, and N-iodosuccinimide
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An efficient and mild method for the halogenation of aromatic compounds using N-chloro-, N-bromo-, and N-iodosuccinimide in the presence of NH 4NO3 or FeCl3 in acetonitrile was developed.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
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p. 932 - 933
(2007/10/03)
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- 1-Aryl-3,3-dialkyltriazenes: A convenient synthesis from dry arenediazonium o-benzenedisulfonimides - A high yield break down to the starting dry salts and efficient conversions to aryl iodides, bromides and chlorides
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This research comprises three parts. The first part regards the synthesis of 1-aryl-3,3-dialkyltriazenes 3 by reaction of dry arenediazonium o-benzenedisulfonimides 1, also coming from weakly basic aromatic amines with dimethylamine or diethylamine in aqueous solution at 0-5 °C. Yields were usually greater than 90% and there was the possibility of recovering the o-benzenedisulfonimide (5), which could be reused to prepare the salts 1. In the second part it was demonstrated that there is the possibility of reconverting the triazenes 3 into the starting stable dry salts 1 by using 5 as acid. The reactions were carried out in glacial acetic acid at 50-55 °C and normally afforded salts 1 in yields of around 90-99%. The third part concerns the setting up of two procedures for the conversion of 3 to aryl iodides 9, bromides 10 and chlorides 11. Procedure A used the corresponding aqueous hydrogen halides in acetonitrile at r.t. or 60 °C, sometimes in the presence of aqueous HBF4, sometimes Cu powder (25 examples, yields 65%-88%). Procedure B usually used anhydrous methanesulfonic acid and tetraalkylammonium halides in anhydrous acetonitrile at temperatures varying from r.t. to 80 °C, sometimes in the presence of Cu (16 examples, yields 65-88%).
- Barbero,Degani,Diulgheroff,Dughera,Fochi
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p. 2180 - 2190
(2007/10/03)
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