- Commercial Ion Exchange Resins as Catalysts in Solid-Solid-Liquid Reactions
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Nucleophilic substitutions, base-catalyzed alkylations, and oxidation of a secondary alcohol have been carried out in a nonpolar solvent with inorganic solid reagents using polymer-bound quarternary ammonium or phosphonium catalysts.The products could be isolated simply by filtration and evaporation of the solvent.Some commercial ion exchange resins, which are known to be inactive in liquid-liquid systems, were found to have a similar or even superior activity in comparison with the usual "triphase catalysts".The resins were chemically stable under the reaction conditions, but their mechanical breakdown could be reduced only by application of unconventional means of agitation.
- Arrad, Onn,Sasson, Yoel
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- Reinterpretation of the kinetic data and the non-steady state hypothesis (two-step mechanism) for the SN2 reaction between p-nitrophenoxide and methyl iodide in aprotic solvents containing water
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Kinetic data obtained by conventional spectrophotometry for reaction of sodium p-nitrophenoxide with methyl iodide in degassed acetone are reported. The rate constants obtained from the first 10% of reaction do not differ significantly from those obtained over longer reaction times (e.g. 50% reaction)-the main criteria of Parker et al. (Org. Biomol. Chem., 2003, 1, 36-38) for a non-steady state two-step mechanism. Reactions are accelerated by crown ether, suggesting a mechanism via a free ion pair. Product studies by high performance liquid chromatography of reactions in aqueous acetonitrile (used by Parker et al.) show that the yield of methylated product is strongly affected by at least two base-neutralising side reactions.
- Humeres, Eduardo,Bentley, T. William
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- Solid state S-methylation of thiols and O-methylation of phenols and naphthols with dimethyl sulfate under microwave irradiation
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Mild and efficient S-methylation of thiols and o-methylation of phenols and naphthals occurs with dimethyl sulfate (DMS) supported on basic alumina under microwave irradiation in solventless system. Copyright Taylor & Francis Inc.
- Heravi, Majid M.,Ahari, Neda Zamani,Oskooie, Hossein A.,Ghassemzadeh, Mitra
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- Ionic liquid effect: Selective aniline oxidative coupling to azoxybenzene by TiO2
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Simple commercially available TiO2 in ionic liquids (ILs) promotes the oxidative catalytic coupling of anilines to diazo compounds. For example, the reaction of aniline with molecular oxygen (5 bars) in the presence of TiO2 and functionalised imidazolium-based ILs affords azoxybenzene in up to 85% selectivity. The catalytic selectivity and activity are mainly related to the viscosity, oxygen solubility, and stability of the superoxide ion (O2-) and ionic species provided by the IL (IL effect). This effect is evident since most of the reactions performed in the presence of ILs gave as major products the azoxybenzene zwitterions. This is in opposition to that performed in toluene, which gave almost exclusively azobenzene.
- Qadir, Muhammad I.,Scholten, Jackson D.,Dupont, Jairton
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- Regioselective Functionalization of 9,9-Dimethyl-9-silafluorenes by Borylation, Bromination, and Nitration
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Despite the utility of 9-silafluorenes as functional materials and as building blocks, methods for efficient functionalization of their backbone are rare, probably because of the presence of easily cleavable C-Si bonds. Although controlling the regioselectivity of iridium-catalyzed direct borylation of C-H bonds is difficult, we found that bromination and nitration of 2-methoxy-9-silafluorene under mild conditions occurred predominantly at the electron-rich position. The resulting product having methoxy and bromo groups can be utilized as a building block for the synthesis of unsymmetrically substituted 9-silafluorene-containing π-conjugated molecules.
- Murai, Masahito,Nishinaka, Naoki,Kimura, Mizuki,Takai, Kazuhiko
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- Manganese-Catalyzed One-Pot Conversion of Nitroarenes into N-Methylarylamines Using Methanol
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A manganese-catalyzed one-pot conversion of nitroarenes into N-methylarylamines has been developed. This transfer hydrogenation method employs a well-defined bench stable Mn PN3P pincer precatalyst in combination with methanol as both the reductant and the C1 source. A selection of commercially available nitroarenes was converted into N-methylarylamines in synthetically useful yields.
- Mast, Nicolas,Morrill, Louis C.,Reed-Berendt, Benjamin G.
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- Copper-catalyzed protodecarboxylation of aromatic carboxylic acids
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A catalyst generated from copper(I) oxide and 4,7-diphenyl-l,10- phenanthroline for the first time allows the catalytic protodecarboxylation even of deactivated aromatic carboxylic acids, giving rise to the corresponding arenes. Based on DFT calculations, a reaction pathway is proposed that accurately reflects the experimental results, such as the observed reactivity order of the substrates.
- Goossen, Lukas J.,Thiel, Werner R.,Rodriguez, Nuria,Linder, Christophe,Melzer, Bettina
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- Electrophilic nitration of aromatics in ionic liquid solvents
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Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Huenig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.
- Laali,Gettwert
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- The oxidation of azo dyes by peroxy acids and tert-butyl hydroperoxide in aqueous solution catalysed by iron(III) 5,10,15,20-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin: Product studies and mechanism
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Product studies on the oxidation of two 1-arylazo-2-hydroxynaphthalene-6-sulfonate dyes by peroxy acids and by tert-butyl hydroperoxide catalysed by iron(III) 5,10,15,20-tetra(2,6-dichloro-2-sulfonatophenyl)porphyrin in solution have been carried out. In
- Hodges, George R.,Smith, John R. Lindsay,Oakes, John
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- Sustainable heck-matsuda reaction with catalytic amounts of diazonium salts: An experimental and theoretical study
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The palladium-catalyzed Heck-Matsuda reaction with a catalytic amount of an in-situ-generated diazonium salt proceeded under mild and sustainable conditions. The reaction proceeded at room temperature, under base-free conditions, and only generated tBuOH, H2O, and N2 as by-products. Ortho-substituted diazonium salts were more-efficiently coupled to methyl acrylate than their corresponding paraisomers, which required the addition of anisole as an additive. In support of these experimental data, we carried out theoretical studies to gain a deeper understanding of these reaction outcomes.
- Susperregui, Nicolas,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Lecallonnec, Francois,Fouquet, Eric,Felpin, Francois-Xavier
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- Facile synthesis of alkyl phenyl ethers using cesium carbonate
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A highly efficient alkylation method of phenols using alkyl halide/cesium carbonate/acetonitrile system is described.
- Lee,Yuk,Cho
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- The synthesis and assay of radiolabelled benzene derivatives
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Several new syntheses of 1- and 4-[14C]anisole have been investigated and routes from [14C]cyanide and from 2-[14C]acetone are described which are better than those previously reported. The key step in one of the syntheses was catalytic dehydrogenation of 1-[14C]cyclohexanone to 1-[14C]phenol. Degradation of 5,6,7,8-tetrachloro-3,4-dihydro-1,4-etheno-[14C]naphthalen-2-(1H)-on e (10) prepared from [14C]anisole and tetrachlorobenzene has shown that the key step had proceeded without scrambling of the label.
- Hales, Neil J.,Heaney, Harry,Hollinshead, John H.,Ley, Steven V.
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- Controlled nitration of anisole over HNO3/PO4/MoO3/SiO2/solvent systems
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Nitroanisoles have wide applications in pharmaceuticals, perfumery and production of corresponding amines used extensively in dye industry. The presence of activated methoxy group in the aromatic ring, causes the nitration of anisole to be complex and dif
- Adamiak, Joanna
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- Anion Activation in the Synthesis of Ethers from Oxygen Anions and 1-Chloro-4-nitrobenzene
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Reactions of 1-chloro-4-nitrobenzene (1) with alkoxide ions in the parent alcohols do not afford satisfactory yields of the expected alkyl 4-nitroaryl ether except in the case of the short-chain primary alcohols.We report that in the model reaction of 1 with KOH in 2-propanol good yields of 1-isopropoxy-4-nitrobenzene (2) are obtained provided Bu4NBr or alkali ion complexing agents such as 18-crown-6, Carbowax 20M, MPEG 5000, and Triton X-100 are present.Low molecular weight ethers, like glyme-5, are less effective, with ethylene glycol dimethyl ether having no effect at all.Work at temperatures below the solution boiling point is recommended to avoid competitive reduction of the NO2 group.The preparative value of Bu4NBr additions in analogous reactions of 1 to give 4-O2NC6H4OR ethers (3) is also very significant when R is primary, secondary, and aryl (1-octyl, sec-butyl, phenyl).The reaction fails when R = tert-butyl and 4-O2NC6H4.
- Paradisi, Cristina,Quintily, Ugo,Scorrano, Gianfranco
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- Oxidation of organonitrogen compounds by the methyltrioxorhenium-hydrogen peroxide system
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Methyltrioxorhenium catalyzes the reaction of hydrogen peroxide with organonitrogen compounds. The reactions are facile and high yield at room temperature of below. The observed chemistry is similar to that previously described by us using dimethyldioxirane as the oxidant.
- Murray, Robert W.,Iyanar, Kaliappan,Chen, Jianxin,Wearing, James T.
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- Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
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A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
- Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
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- Solvent-free iodination of arenes using iodine-silver nitrate combination
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A simple and environmentally safe general method of iodination of aromatic substrates under sovent-free conditions using the I2/AgNO3 combination in a solid state is reported. Both activated and deactivated aromatic compounds afford the respective aryl iodides in generally high yields (80-90%). Copyright Taylor & Francis Group, LLC.
- Yusubov, Mekhman S.,Tveryakova, Elena N.,Krasnokutskaya, Elena A.,Perederyna, Irina A.,Zhdankin, Viktor V.
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- Microwave-assisted methylation of carboxylic acids and phenolic compounds with dimethyl-carbonate under solvent-free condition
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Phenolic compounds and carboxylic acids are methylated with dimethyl carbonate in the presence of a catalytic amount of BF3· OEt2, DBU, or KOH, in good to excellent yields under microwave irradiation and solvent-free conditions.
- Rajabi, Fatemeh,Saidi, Mohammad R.
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- Cross-coupling reaction with lithium methyltriolborate
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We newly developed lithium methyltriolborate as an air-stable white solid that is convenient to handle. The good performance of this triolborate for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions wi
- Yamamoto, Yasunori,Ikizakura, Kazuya,Ito, Hajime,Miyaura, Norio
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- An unconventional cobalt-catalyzed aerobic oxidation of tertiary nitrogen compounds to N-oxides
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A simple system, simple workup, and excellent yields make the new method for the oxidation of tertiary nitrogen compounds described in Equation (1) an attractive, environmentally acceptable synthetic tool. Molecular oxygen serves as the oxygen source and no sacrificial agents are required.
- Jain, Suman L.,Sain, Bir
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- Relative reactivity of methyl iodide to ethyl iodide in nucleophilic substitution reactions in acetonitrile and partial desolvation accompanying activation
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Through the examination of empirical correlations involving activation parameters for nucleophilic substitution of methyl iodide and of ethyl iodide, nucleophiles have been classified into three series: (1) nucleophiles with two equivalent reaction sites, (2) nucleophiles with a chlorine atom in the para-position, and (3) nucleophiles with a single reaction site. Three types of partial desolvation processes accompanying activation have been deduced on the basis of these classifications. A major factor determining the relative reactivity of methyl iodide to ethyl iodide in the substitution reaction of an anionic nucleophile having a single reaction site in acetonitrile (kMeI/kEtI) is suggested to be partial desolvation around the nucleophilic center on going from reactant to transition-state.
- Kondo, Yasuhiko,Urade, Miyuki,Yamanishi, Yukari,Chen, Xinyu
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- Selective O-methylation of phenols and benzyl alcohols in simple pyridinium based ionic liquids
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Synthesis of pyridinium based ionic liquids were reported and applied as catalyst for the selective O-methylation of phenols and benzyl alcohols. The reactions were carried out by using dimethylcarbonate (DMC) as the methylating agent. High selectivity, high yield and recyclability of the ionic liquids are important features of the reactions.
- Das, Pranab Jyoti,Das, Jupitara
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- Bis(μ-iodo)bis[(-)-sparteine]-dicopper: A versatile catalyst for direct O-Arylation and O-Alkylation of phenols and aliphatic alcohols with haloarenes
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The easy to prepare dimeric bis(μ-iodo)bis[(-)-sparteine]- dicopper ([CuI{(-)-spa}]2 complex) is shown to be versatile catalyst for O-arylation and O-alkylation with various aryl halides with phenols and aliphatic alcohols respectively, including less reactive aryl chlorides, such as chlorobenzene under mild conditions.
- Satyanarayana, Ponnam,Maheswaran, Hariharasarma,Kantam, Mannepalli Lakshmi,Bhargava, Suresh
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- Mitsunobu reaction modifications allowing product isolation without chromatography: Application to a small parallel library
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Readily available reagents, triphenylphosphine resin and di-t- butylazodicarboxylate, were used in Mitsunobu reactions and the byproducts were removed without chromatography. The new modification was utilized to prepare a small, parallel, solution phase library. (C) 2000 Elsevier Science Ltd.
- Pelletier, Jeffrey C.,Kincaid, Scott
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- EffectiveN-methylation of nitroarenes with methanol catalyzed by a functionalized NHC-based iridium catalyst: a green approach toN-methyl amines
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Compound [IrBr(CO)2(κC-tBuImCH2PyCH2OMe)] featuring a flexible pyridine/OMe functionalized NHC ligand κ1C coordinated efficiently catalyzes the selectiveN-monomethylation of nitroarenes using methanol as both the reducing agent and the C1 source. A range of functionalized nitroarenes including heterocyclic or sterically hindered derivatives have been efficiently converted to the correspondingN-monomethyl amines in good yields at low catalyst loadings using sub-stoichiometric amounts of Cs2CO3as a base. Mechanistic investigations support a borrowing-hydrogen mechanism in which methanol acts as the hydrogen source and methylating agent. Further, the hydrogen transfer reduction of nitrobenzene to aniline under optimized reaction conditions should proceed through a direct mechanism involving nitrosobenzene andN-phenylhydroxylamine intermediates.
- González-Lainez, Miguel,Jiménez, M. Victoria,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.
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- Perfluorocarbon soluble crown ethers as phase transfer catalysts
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Fluorous derivatives of dibenzo-18-crown-6 ether were readily prepared by means of metal-catalyzed cross-coupling reactions, and then successfully applied as catalysts in representative solid-liquid phase transfer catalysis (PTC) reactions, which were performed in standard organic solvents, such as chlorobenzene and toluene, and also in fluorous solvents, such as perfluoro-1,3-dimethylcyclohexane (PFDMC). It was clearly shown that properly designed fluoroponytailed crown ethers can promote the disintegration of the crystal lattice of alkali salts and transfer anions from the solid surface into an apolar, non-coordinating perfluorocarbon phase. Far from beinga simple chemical curiosity, this unprecedented observation has relevant implications in the design of PTC scenarios of wide applicability. This new paradigm represents an advance in crown ether chemistry, and their use as recyclable phase transfer catalysts.
- Pozzi, Gianluca,Quici, Silvio,Fish, Richard H.
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- Multinuclear Magnetic Resonance Spectroscopic and Semiempirical Molecular Orbital (AM1) Studies of Substituted Anisoles
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13C, 15N, and 17O NMR spectra have been recorded for 4-nitroanisole (1), its 2-methyl-, 2-chloro-, 2-bromo-, 2-iodo-, 2,6-diamethyl-, 2,6-dichloro, 2,6-dibromo-, and 2,6-diiodo-derivatives 2-9, also nitrobenzene (1a), its 3-methyl-, 3-chloro-, 3-bromo-, and 3-iodo-derivatives 2a-5a and 3,5-dichloro- and 3,5-dibromo-derivatives 7a and 8a.Analysis of the chemical shifts of carbon bearing nitro group and nitro oxygens in these compounds suggests that presence of one substituent ortho- to the methoxyl group enhances its resonance interaction with the benzene ring whereas presence of two ortho-substituents inhibits this resonance.However, in no case the resonance is completely inhibited.The extent of enhancement or inhibition is almost independent of the nature of the ortho-substituent.This conclusion has also been arrived by analyzing the reported chemical shifts of the para-carbons in anisoles 1b-9b and the corresponding carbons in benzene derivatives 1c-9c.Though evidence could not be obtained for steric enhancement of resonance using methoxyl oxygen chemical shifts, analysis of these chemical shifts in di-ortho-substituted anisoles 6-9 and 6a furnishes evidence for steric inhibition of resonance.However, 15N chemical shifts are of no use in studying these phenomena.Semiempirical molecular orbital calculations using AM1 Hamiltonian suggest that the methoxyl group is coplanar with the benzene ring in anisole, 4-nitroanisole and 2-substituted-4-nitroanisoles but is perpendicular to the benzene ring in 2,6-disubstituted-4-nitroanisoles.Moreover, in 2-substituted-4-nitroanisoles the O-methyl group is anti to the 2-substituent.
- Pandiarajan, Karuppiah,Kabilan, Senthamaraikannan,Sankar, Punnaivanam,Kolehmainen,Erkki,Nevalainen, Tapio,Kauppinen, Reijo
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- Catalyst-free ipso-nitration of aryl boronic acids using bismuth nitrate
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We report a catalyst-free ipso-nitration of aryl boronic acids using bismuth (III) nitrate as nitrating agent. Reaction proceeds in shorter reaction times with moderate to excellent yields. This method is operationally simple, regioselective, and possesses excellent functional group compatibility to synthesize nitroarenes.
- Yadav, Rammohan R.,Vishwakarma, Ram A.,Bharate, Sandip B.
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- New and efficient method for esterification of carboxylic acids with simple primary and secondary alcohols using cerium(IV) ammonium nitrate (CAN)
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The esterification of phenylacetic acids and cis-oleic acid with primary and secondary simple alcohols, which also act as solvents using cerium(IV) ammonium nitrate (CAN) at room temperature gave phenylacetates and methyl (9Z)-octadec-9-enoate. The reactions, which occur under relatively mild conditions, afforded the desired products in good to excellent yields.
- Pan, Wen-Bin,Chang, Fang-Rong,Wei, Li-Mei,Wu, Ming-Jung,Wu, Yang-Chang
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- A new protocol for O-methylation of phenolic compounds with trimethyl phosphite or trimethyl phosphate under solvent-free condition and microwave irradiation
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A simple method for the preparation of industrially important alkyl aryl ethers is reported. Several phenolic compounds such as phenols, naphthols, and hydroxy coumarins were O-methylated with trimethyl phosphite or trimethyl phosphate under microwave irradiation and solvent-free condition in almost quantitative yields. Reaction of 2-naphthol with trimethyl phosphate gave mixture of 2-methoxynaphthalene and 1-methyl-2-methoxynaphthalene while the reaction with trimethyl phosphite gave mostly 2-methoxynaphthalene. This method is highly efficient for the methylating of phenolic compounds with very easy experimental procedure and environmental friendly conditions.
- Saidi, Mohammad R.,Rajabi, Fatemeh
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- Convenient and mild synthesis of nitroarenes by metal-free nitration of arylboronic acids
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A novel methodology for the direct nitration of arylboronic acids has been developed. By using inexpensive tert-butyl nitrite various aromatic nitro compounds are produced in moderate to good yields (45-87%) without the need of any catalyst.
- Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
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- Solvent Effects in the Two-phase Nitration of Anisole
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Depending on the nature of the organic solvent, anisole can be quantitatively nitrated by 65percent nitric acid in a nitrite-catalysed two-phase system.
- Germain, Alain
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- A novel route to organonitrites by Pd-catalyzed cross-coupling of sodium nitrite and potassium organotrifluoroborates
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Microwave irradiated palladium-catalyzed cross-coupling reaction of potassium styryltrifluoroborates and sodium nitrite gives the corresponding styryl nitrites in high yields. Potassium aryltrifluoroborates also furnish aryl nitrites under same reaction condition. This unprecedented cross-coupling is an interesting development and has the potential to lead to new nitration protocols.
- Al-Masum, Mohammad,Saleh, Nabil,Islam, Tasfia
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- Ion-dipole SN2 reaction in acetone - Water mixtures. Electrostatic and specific solute - Solvent interactions
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The rate constants of the SN2 reaction of sodium 4-nitrophenoxide (1) and iodomethane were determined by UV - visible spectrophotometry in acetone - water mixtures at 25, 30, and 35 °C. The rate - Xwater (mole fraction of water) profile shows that the reaction depends strongly on the medium. The fastest rate constant was obtained in pure acetone, and a minimum occurred at Xwater = 0.4, whereas the observed second-order rate constants k′2 increases again in the water-rich region. In pure acetone, in the presence of dicyclohexano-[18]-crown-6, k′2 increases linearly with the concentration of the crown ether as a result of the complexation of the sodium ion (KS = 104.8 M) of the ion-pair and the increase in the effective concentration of free 4-nitrophenoxide ion, which was assumed to be the only reactive species. Ion-pairing was also detected at Xwater = 0.65 with a dissociation constant Kd = 7.82 × 10-4 M-1. The solvatochromic behaviors of 2,6-diphenyl-4-(2,4,6triphenyl-1-pyridinio)-1-phenoxide(2),4- [(1-methyl-4(1H)-pyridinylidene)ethylidene]-2,5-cyclohexadien-1-one (3), and 1-methyl-8-oxy-quinolinium betaine (4) were investigated in the entire range of acetone - water mixtures. The dyes presented an increasing order of hydrophilicity compatible with their chemical structure, i.e., 2 T values of the dyes show a linear correlation of the polarity in the region of Xwater = 1.0-0.40 for 3 and 4, and it was observed that the more hydrophilic the dye the better the correlation coefficient, because of the structural similarity with 1. The activation parameter - Xwater profile shows extrema at Xwater + and 4-nitrophenoxide that extends even to water-rich mixtures. A model, based on the assumption that the free-energy terms involved in the second-order rate constant and the dissociation constant of the ion-pair have two components, is invoked to explain the kinetic data. One of the components depends on electrostatic interactions for which the main variable is the dielectric constant of the solvent mixture, and the other depends on the specific solute - solvent interactions, expressed by the activity coefficients of transfer of the species involved. The model indicates that in the range of Xwater = 1.0-0.40 the interactions are exclusively electrostatic, while for the rest of the acetone-rich region they are specific with a large contribution of the 4-nitrophenoxide ion.
- Humeres,Nunes,Machado,Gasques,Machado
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- Non-steady-state kinetic study of the SN2 reaction between p-nitrophenoxide ion and methyl iodide in acetonitrile
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Non-steady-state kinetic study of the SN2 reaction between p-nitrophenoxide ion and methyl iodide in acetonitrile was presneted. Analysis of non-steady-state kinetic data for the reaction with tetrabutylammonium counter ions in acetonitrile in
- Parker, Vernon D.,Lu, Yun
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- Transition Metal Porphyrins as Catalysts in the Oxidation of Nitroso Compounds
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Iron(III) and manganese(III) porphyrins are found to be very effective catalysts for the oxidation of nitroso to nitro compounds, even at -78 deg C.
- Joergensen, Karl Anker
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- Kinetic and spectroscopic studies of aerobic copper(II)-catalyzed methoxylation of arylboronic esters and insights into aryl transmetalation to copper(II)
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We previously reported a preliminary mechanistic study of aerobic Cu(OAc)2-catalyzed methoxylation of 4-tolylboronic ester (King et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to CuII is the turnover-limiting step. In the present study, more thorough kinetic and spectroscopic studies provide additional insights into the transmetalation pathway and identity of the CuII catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions, and their relative populations vary as a function of reaction time and acidity of the arylboronic ester and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and 11B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic CuII species, mediated by a methoxide bridge.
- King, Amanda E.,Ryland, Bradford L.,Brunold, Thomas C.,Stahl, Shannon S.
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- Microwave-assisted methylation of phenols with DMF-DMA
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We evaluated the potential of N,N-dimethylformamide dimethylacetal (DMF-DMA) as a methylating agent for a library of para-substituted phenols under microwave irradiation. The rate of reaction was dictated by the electronic nature of the para-substituent. With an electron-withdrawing group the reaction was completed within 30 min. For electron-donating groups, the reaction times were 60 min. Esterification and enamino-ketone formation was also observed with carboxylic acid and ketone functional groups, respectively.
- Belov, Pavel,Campanella, Veronica L.,Smith, Alison W.,Priefer, Ronny
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- Non-steady-state kinetic study of the SN2 reaction between p-nitrophenoxide ion and methyl iodide in aprotic solvents containing water. Evidence for a 2-step mechanism
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Non-steady-state kinetic studies reveal that the SN2 reaction between p-nitrophenoxide ion and methyl iodide in acetonitrile containing water follows a 2-step mechanism involving the formation of a kinetically significant intermediate.
- Lu, Yun,Handoo,Parker, Vernon D.
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- Eco-Friendly Methodology for the Formation of Aromatic Carbon–Heteroatom Bonds by Using Green Ionic Liquids
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A new sustainable method is reported for the formation of aromatic carbon–heteroatom bonds under solvent-free and mild conditions (no co-oxidant, no strong acid and no toxic reagents) by using a new type of green ionic liquid. The bromination of methoxy arenes was chosen as a model reaction. The reaction methodology is based on only using natural sodium bromine, which is transformed into an electrophilic brominating reagent within an ionic liquid, easily prepared from the melted salt FeCl3 hexahydrate. Bromination reactions with this in-situ-generated reagent gave good yields and excellent regioselectivity under simple and environmentally friendly conditions. To understand the unusual bromine polarity reversal of sodium bromine without any strong oxidant, the molecular structure of the reaction medium was characterised by Raman and direct infusion electrospray ionisation mass spectroscopy (ESI-MS). An extensive computational investigation using density functional theory methods was performed to describe a mechanism that suggests indirect oxidation of Br? through new iron adducts. The versatility of the methodology was successively applied to nitration and thiocyanation of methoxy arenes using KNO3 and KSCN in melted hexahydrated FeCl3.
- Richards, Kenza,Petit, Eddy,Legrand, Yves-Marie,Grison, Claude
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supporting information
p. 809 - 814
(2020/11/30)
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- 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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- Microwave-induced surface-mediated highly efficient regioselective nitration of aromatic compounds: Effects of penetration depth
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Surface mediated highly regioselective nitration of aromatic compounds under diverse microwave-induced conditions was investigated in this work. The effects of the penetration depth of the surfaces were found to be more crucial than other dielectric parameters. Despite significant progress of microwave-induced reactions, no reports have examined the penetration depth of the surfaces used in these processes.
- BANIK, BIMAL K.,DAS, APARNA,YADAV, RAM NARESH
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p. 2203 - 2206
(2021/08/24)
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- Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3O4 Nanoparticles
-
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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-
- Cu-Catalyzed Phenol O-Methylation with Methylboronic Acid
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A Cu-catalyzed oxidative cross-coupling of phenols with methylboronic acid to form aryl methyl ethers has been developed, expanding the scope of Chan-Evans-Lam alkylation. Electron-deficient phenol derivatives with a broad array of functional groups are methylated in high yields. Increased reaction temperature and catalyst loading enables the methylation of substrates incorporating pyridine and dihydroquinolone motifs. Electron-rich phenol derivatives are poor substrates for the methylation; the characterization of C?H homodimerization products formed from these substrates illuminates a competing mechanistic pathway.
- Bartlett, Mairead E.,Chavez, Angela K.,Gaffney, Uma Bhagwat,Gorin, David J.,Lee, Joyce,Sharew, Betemariam,Wu, Miranda,Zhu, Yingchuan
-
supporting information
p. 5661 - 5664
(2021/11/11)
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- Synthetic method of p-nitroanisole
-
The invention relates to the technical field of organic intermediates, and particularly discloses a p-nitroanisole synthesis method. The method includes the steps: S1 dissolving p-nitroanisole, and dissolving sodium hydroxide and methanol in an organic so
- -
-
Paragraph 0038-0107
(2021/03/13)
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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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- Crystallography-guided discovery of carbazole-based retinoic acid-related orphan receptor gamma-t (RORγt) modulators: insights into different protein behaviors with “short” and “long” inverse agonists
-
A series of 6-substituted carbazole-based retinoic acid-related orphan receptor gamma-t (RORγt) modulators were discovered through 6-position modification guided by insights from the crystallographic profiles of the “short” inverse agonist 6. With the increase in the size of the 6-position substituents, the “short” inverse agonist 6 first reversed its function to agonists and then to “long” inverse agonists. The cocrystal structures of RORγt complexed with the representative “short” inverse agonist 6 (PDB: 6LOB), the agonist 7d (PDB: 6LOA) and the “long” inverse agonist 7h (PDB: 6LO9) were revealed by X-ray analysis. However, minor differences were found in the binding modes of “short” inverse agonist 6 and “long” inverse agonist 7h. To further reveal the molecular mechanisms of different RORγt inverse agonists, we performed molecular dynamics simulations and found that “short” or “long” inverse agonists led to different behaviors of helixes H11, H11’, and H12 of RORγt. The “short” inverse agonist 6 destabilizes H11’ and dislocates H12, while the “long” inverse agonist 7h separates H11 and unwinds H12. The results indicate that the two types of inverse agonists may behave differently in downstream signaling, which may help identify novel inverse agonists with different regulatory mechanisms.
- Yu, Ming-cheng,Yang, Feng,Ding, Xiao-yu,Sun, Nan-nan,Jiang, Zheng-yuan,Huang, Ya-fei,Yan, Yu-rong,Zhu, Chen,Xie, Qiong,Chen, Zhi-feng,Guo, Si-qi,Jiang, Hua-liang,Chen, Kai-xian,Luo, Cheng,Luo, Xiao-min,Chen, Shi-jie,Wang, Yong-hui
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p. 1524 - 1534
(2020/12/01)
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- Exploiting a silver-bismuth hybrid material as heterogeneous noble metal catalyst for decarboxylations and decarboxylative deuterations of carboxylic acids under batch and continuous flow conditions
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Herein, we report novel catalytic methodologies for protodecarboxylations and decarboxylative deuterations of carboxylic acids utilizing a silver-containing hybrid material as a heterogeneous noble metal catalyst. After an initial batch method development, a chemically intensified continuous flow process was established in a simple packed-bed system which enabled gram-scale protodecarboxlyations without detectable structural degradation of the catalyst. The scope and applicability of the batch and flow processes were demonstrated through decarboxylations of a diverse set of aromatic carboxylic acids. Catalytic decarboxylative deuterations were achieved on the basis of the reaction conditions developed for the protodecarboxylations using D2O as a readily available deuterium source.
- ?tv?s, Sándor B.,Fül?p, Ferenc,Kónya, Zoltán,Kukovecz, ákos,Márton, András,Mészáros, Rebeka,Pálinkó, István,Szabados, Márton,Varga, Gábor
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p. 4685 - 4696
(2021/07/12)
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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
-
-
- P-nitroanisole synthesis method
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The invention relates to a synthetic method of p-nitroanisole, which can effectively reduce the generation of by-products, avoid the refining process of the by-product p-nitrophenol and greatly improve the yield of p-nitroanisole; besides, a small amount of p-nitrophenol can be further reused in the synthetic steps of the invention in the subsequent wastewater treatment process. In addition, the p-nitroanisole obtained by the method disclosed by the invention has higher product quality.
- -
-
Paragraph 0027-0046; 0050-0053
(2020/09/20)
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- Clean production process for producing nitrobenzene alkoxy ether by using nitrohalogenated benzene
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The invention provides a clean production process for producing nitrobenzene alkoxy ether by using nitrohalogenated benzene. The specific production steps comprise: proportionally adding one or more than one non-polar solvents into a reactor, adding molten nitrohalogenated benzene into the reactor, uniformly stirring, and adding alkali metal alkoxide into the reactor at a constant speed; after thereaction is finished, adding water to washing the inorganic matters generated in the reaction process while recovering the solvent. According to the invention, the production process is simple, the catalyst separation efficiency in the reaction process is high, other substances irrelevant to the reaction are not added in the reaction process, the purity is high, the yield is high, byproducts arelow, the wastewater amount is low, and the reaction period is short; and the reaction device is operated in a totally-enclosed manner, so that the operation environment is improved, the harm to humanhealth is reduced, and the cost is saved.
- -
-
Paragraph 0037-0042
(2020/06/09)
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- Aryl Ether Syntheses via Aromatic Substitution Proceeding under Mild Conditions
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In this study, mild conditions for aromatic substitutions during the syntheses of aryl ethers were developed. In the reaction conditions, the choices of solvent, base, and the sequence for the addition of the reagents proved important. A wide variety of alcohols were used directly as nucleophiles and smoothly reacted with aryl chlorides that possessed either a nitro or a cyano group at either the ortho- or para-position. Controlled experiments we performed suggested that the reaction underwent a charge-transfer process mediated by a combination of DMF and tert-BuOK.
- Ando, Shin,Tsuzaki, Marina,Ishizuka, Tadao
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p. 11181 - 11189
(2020/10/12)
-
- 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.
- -
-
Page/Page column 36; 41; 46; 64; 37; 42; 46-47
(2020/05/28)
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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
-
supporting information
(2020/03/30)
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- Light assisted O-alkylation of phenols to ethers using layered double oxides catalyst under green and mild conditions
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O-alkylation of phenols with dialkyl carbonates to ethers over layered double oxides (LDOs) catalyst under light irradiation is described. A base additive is not required when using the longer-chain diethyl carbonate as an alkylating agent owing to the sufficient basicity provided by LDOs. The synergism of substrate phenols molecules absorbing light to reach the first excited states with acid–base pairs of catalyst enhanced the interaction of reactant molecules with the surface of LDOs, simultaneously accelerating the cleavage of phenolic hydroxyl groups. A variety of phenols are tolerated in this system. This work reports a simple and environmentally benign catalytic process for the dehydrogenation of phenolic hydroxyl groups.
- Wang, Ruiyi,Wang, Xiaoyu,Zheng, Zhanfeng
-
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- 3-(Ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium cation: A green alternative to tert-butyl nitrite for synthesis of nitro-group-containing arenes and drugs at room temperature
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Due to their remarkable properties, task-specific ionic liquids have turned out to be progressively popular over the last few years in the field of green organic synthesis. Herein, for the first time, we report that a new task-specific nitrite-based ionic liquid such as 3-(ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium bis(trifluoromethanesulfonyl)imides (TS-N-IL) derived from biodegradable ethyl nicotinate indeed acted as an efficient and eco-friendly reagent for the synthesis of highly valuable nitroaromatic compounds and drugs including nitroxynil, tolcapone, niclofolan, flutamide, niclosamide and nitrazepam. The bridging of an ionic liquid with nitrite group not only increases the yield and rate of direct C[sbnd]N bond formation reaction but also allows easy product separation and recyclability of a byproduct. Nonvolatile nature, easy synthesis, merely stoichiometric need and mildness are a portion of the extra focal points of TS-N-IL while contrasted with tert-butyl nitrite an outstanding and highly-flammable reagent utilized largely in organic synthesis.
- Chaudhary, Renu,Natarajan, Palani,Rani, Neetu,Sakshi,Venugopalan, Paloth
-
supporting information
(2019/12/30)
-
- Regioselective Functionalization of 9,9-Dimethyl-9-silafluorenes by Borylation, Bromination, and Nitration
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Despite the utility of 9-silafluorenes as functional materials and as building blocks, methods for efficient functionalization of their backbone are rare, probably because of the presence of easily cleavable C-Si bonds. Although controlling the regioselectivity of iridium-catalyzed direct borylation of C-H bonds is difficult, we found that bromination and nitration of 2-methoxy-9-silafluorene under mild conditions occurred predominantly at the electron-rich position. The resulting product having methoxy and bromo groups can be utilized as a building block for the synthesis of unsymmetrically substituted 9-silafluorene-containing ?-conjugated molecules.
- Murai, Masahito,Nishinaka, Naoki,Kimura, Mizuki,Takai, Kazuhiko
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p. 5667 - 5676
(2019/05/10)
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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)
-
- Synthesis method of aromatic nitro-compound
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The invention discloses a synthesis method of an aromatic nitro-compound. The synthesis method is characterized in that the aromatic nitro-compound is obtained by taking an aromatic amino-compound asa raw material and performing an oxidation reaction on the aromatic amino-compound and peroxytrifluoroacetic acid. The target aromatic nitro-compound is obtained by taking the aromatic amino-compoundas the raw material and performing the oxidation reaction on the aromatic amino-compound and peroxytrifluoroacetic acid; the synthesis method is high in yield, wide in application range, simple in operation and little in environmental pollution, therefore, the synthesis method is a good and ideal method for preparing the aromatic nitro-compound.
- -
-
Paragraph 0049; 0053
(2019/10/29)
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- Catalytic Selective Oxidative Coupling of Secondary N-Alkylanilines: An Approach to Azoxyarene
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Azoxyarenes are among important scaffolds in organic molecules. Direct oxidative coupling of primary anilines provides a concise fashion to construct them. However, whether these scaffolds can be prepared from secondary N-alkylanilines is not well explored. Here, we present a catalytic selective oxidative coupling of secondary N-alkylaniline to afford azoxyarene with tungsten catalyst under mild conditions. In addition, azoxy can be viewed as a bioisostere of alkene and amide. Several "azoxyarene analogues" of the corresponding bioactive alkenes and amides showed comparable promising anticancer activities.
- Ke, Lei,Zhu, Guirong,Qian, Hui,Xiang, Guangya,Chen, Qin,Chen, Zhilong
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supporting information
p. 4008 - 4013
(2019/06/04)
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- A new alkylation of aryl alcohols by boron trifluoride etherate
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The ethylation of aryl alcohols by an ethyl moiety of boron trifluoride etherate is described. The reaction proceeded cleanly and afforded good yields of the corresponding aryl ethyl ethers. It tolerated the presence of functional groups such as aryl, alkyl, halogens, nitro, nitrile, and amino. However, the presence of amino or nitro groups ortho to a hydroxyl group of an aryl compound drastically reduced the yields of the anticipated products due to the chelation of the aforementioned functional groups with boron trifluoride etherate. A nitrogen atom in the aromatic ring system, as exemplified by hydroxypyridine and 8-hydroxyquinoline, completely inhibited the reaction. Resorcinol, hydroquinone, and aryl alcohols with aldehyde functions decomposed under the reaction conditions.
- Jumbam, Ndze Denis,Maganga, Yamkela,Masamba, Wayiza,Mbunye, Nomthandazo I.,Mgoqi, Esethu,Mtwa, Sphumusa
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- Ligand-free Cu(ii)-catalyzed aerobic etherification of aryl halides with silanes: An experimental and theoretical approach
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Owing to their wide occurrence in nature and immense applications in various fields, the synthesis of aryl alkyl ethers has remained a focus of interest. In contrast to the conventional/traditional methods of etherification, herein, we have reported a more efficient method, which is better yielding and more general in application. The etherification of aryl halides by alkoxy/phenoxy silanes was catalyzed by copper acetate in the presence of cesium carbonate and oxygen in DMF at 145 °C. All the as-synthesized compounds were characterized via the 1H-NMR and 13C-NMR spectroscopic techniques. Density functional theory calculations using the B3LYP functional were performed to elucidate the reaction mechanism. The C-O coupling reaction between 2-nitroiodobenzene and tetramethoxysilane was used as a model reaction. The activation energy barriers for the generation of catalytic species (31.6 kcal mol-1) and the σ-bond metathesis (16.0 kcal mol-1), oxidative addition/reductive elimination (20.3 kcal mol-1), halogen atom transfer (19.2 kcal mol-1) and single electron transfer (SET) (29.5 kcal mol-1) mechanisms for the C-O coupling reaction were calculated. Calculations for the key reaction steps were repeated with the B3PW91, PBEH1PBE, wB97XD, CAM-B3LYP and mPW1LYP functionals. The formation of catalytic species via a single electron transfer reaction between tetramethoxysilane and copper acetate, formation of methoxy radicals and methoxylation of copper showed an overall energy barrier of 31.6 kcal mol-1, and therefore is the rate determining step.
- Ahmed, Muhammad Naeem,Ahmad, Khalil,Yasin, Khawaja Ansar,Farooq, Tayyaba,Khan, Bilal Ahmad,Roy, Soumendra K.
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p. 11316 - 11333
(2019/07/31)
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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
-
-
- 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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- Benzimidazolium-based high temperature ionic liquid-in-oil microemulsion for regioselective nitration reaction
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Owing to the fascinating applications of ionic liquids (ILs) based non-aqueous microemulsions (MEs) in the field of chemical reactions due to their high thermal stability compared to that of aqueous MEs and requirement of water-free environment, we design
- Kar, Barnali,Ghosh, Prasanjit,Kundu, Kaushik,Bardhan, Soumik,Paul, Bidyut K.,Das, Sajal
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p. 122 - 130
(2018/07/25)
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- HNO3/HFIP: A Nitrating System for Arenes with Direct Observation of π-Complex Intermediates
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This report describes an efficient nitrating system for the nitration of arenes at room temperature by using an equivalent of nitric acid in HFIP (1,1,1,3,3,3-hexafluoroisopropanol). The π-complex intermediate of an arene with a nitronium ion stabilized by HFIP can be directly observed by UV-vis spectra and is supported by theoretical calculations.
- Lu, Le,Liu, Huixin,Hua, Ruimao
-
supporting information
p. 3197 - 3201
(2018/06/11)
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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 0069; 0070
(2018/09/11)
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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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- 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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- A 2 - amino - 4 - acetyl amino methyl ether synthesis method (by machine translation)
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The invention discloses a 2 - amino - 4 - acetyl amino methyl ether synthesis method. The synthetic method comprises the following steps: (1) in the presence of a catalyst A, to nitroanisole with hydrogen by a catalytic hydrogenation reduction reaction to obtain the amino anisole; (2) P a the fuel to the acetylation reaction acetyl amino anisole; (3) to the acetaminophen a fuel for nitration reaction to obtain the 2 - nitro - 4 - acetamido anisole; (4) in the presence of a catalyst B, 2 - nitro - 4 - acetyl amino methyl ether with hydrogen by secondary catalytic hydrogenation reduction reaction. This invention adopts the first acylation, re-nitration, reduction method for synthesis of 2 - amino - 4 - acetyl amino methyl ether, avoids the traditional directional acylate raw material is easy to oxidation in the process, a plurality of side reaction, the product is hard to separate, the problem of low purity, the method of the invention the synthetic product purity can be up to 99.5% -99.8%. (by machine translation)
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Paragraph 0062-0064
(2018/05/01)
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- Industrial production method for 2-amino-4-acetamidoanisole
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The invention discloses an industrial production method for 2-amino-4-acetamidoanisole. The industrial production method comprises the following steps: (1) allowing paranitroanisole and hydrogen to undergo a catalytic hydrogenation reduction reaction in the presence of a catalyst A so as to obtain p-aminoanisole; (2) allowing the p-aminoanisole to undergo an acetylation reaction so as to obtain p-acetamidoanisole; (3) allowing the p-acetamidoanisole to undergo a nitration reaction so as to obtain 2-nitro-4-acetamidoanisole; and (4) allowing 2-nitro-4-acetamidoanisole and hydrogen to undergo two catalytic hydrogenation reduction reactions in the presence of a catalyst B so as to obtain the 2-amino-4-acetamidoanisole. The production method provided by the invention has the characteristics oflow production cost, high reaction selectivity, simple separation process, high product purity, no three wastes in the process of production, recyclability and continuous large-scale industrial production, and solves the disadvantages of high separation cost, low product purity, and large discharge amount and difficult treatment of three wastes in the prior art.
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-
Paragraph 0055; 0057
(2018/04/03)
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- Reductive Denitration of Nitroarenes
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The Pd-catalyzed reductive denitration of nitroarenes has been achieved via a direct cleavage of the C-NO2 bonds. The catalytic conditions reported exhibit a broad substrate scope and good functional-group compatibility. Notably, the use of inexpensive propan-2-ol as a mild reductant suppresses the competitive formation of anilines, which are normally formed by other conventional reductions. Mechanistic studies have revealed that alcohols serve as efficient hydride donors in this reaction, possibly through β-hydride elimination from palladium alkoxides.
- Kashihara, Myuto,Yadav, M. Ramu,Nakao, Yoshiaki
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supporting information
p. 1655 - 1658
(2018/03/23)
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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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- 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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- Transition-metal-free hydrogenation of aryl halides: From alcohol to aldehyde
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A transition-metal-and catalyst-free hydrogenation of aryl halides, promoted by bases with either aldehydes or alcohols, is described. One equivalent of benzaldehyde affords an equal yield as that of 0.5 equiv of benzyl alcohol. The kinetic study reveals that the initial rate of PhCHO is much faster than that of BnOH, in the ratio of nearly 4:1. The radical trapping experiments indicate the radical nature of this reaction. Based on the kinetic study, trapping and KIE experiments, and control experiments, a tentative mechanism is proposed. As a consequence, a wide range of (hetero)aryl iodides and bromides were efficiently reduced to their corresponding (hetero)arenes. Thus, for the first time, aldehydes are directly used as hydrogen source instead of other well-established alcohol-hydrogen sources.
- Zheng, Hong-Xing,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5114 - 5117
(2017/11/07)
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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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- Organocatalytic oxidation of substituted anilines to azoxybenzenes and nitro compounds: Mechanistic studies excluding the involvement of a dioxirane intermediate
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An organocatalytic and environmentally friendly approach for the selective oxidation of substituted anilines was developed. Utilizing a 2,2,2-trifluoroacetophenone-mediated oxidation process, substituted anilines can be transformed into azoxybenzenes, while a simple treatment with MeCN and H2O2 leads to the corresponding nitro compounds, providing user-friendly protocols that can be easily scaled up. Various substitution patterns and functional groups were tolerated leading to products in high to excellent yields. Mechanistic studies utilizing HRMS provide clear evidence for the distinct mechanistic intermediates that are involved. This study constitutes an indirect proof excluding the involvement of a dioxirane intermediate in the green organocatalytic oxidation, utilizing 2,2,2-trifluoroacetophenone as the catalyst.
- Voutyritsa, Errika,Theodorou, Alexis,Kokotou, Maroula G.,Kokotos, Christoforos G.
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supporting information
p. 1291 - 1298
(2017/06/06)
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- The heliconical nematic twist-bend phase from “classic” bent-core benzylideneanilines with oligomethylene cores
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We report the synthesis and properties of several new heliconical twist-bend nematic (NTB) bimesogens possessing “classic” bent-core benzylideneaniline wings combined with oligomethylene spacers of odd parity. While short alkoxy tails combined with a resorcinol diester core in the classic system appear to give SmA phases (not B2 phases), in the present system, methoxy or ethoxy tails exhibit the NTB phase as evidenced by textural analysis. Several of these compounds also exhibit microscopic helical defect structures in the NTB phase, which have been reported in other lamellar and pseudo-lamellar liquid crystal phases, but not in the NTB phase.
- Scarbrough, Alyssa N.,Tuchband, Michael R.,Korblova, Eva D.,Shao, Renfan,Shen, Yongqiang,Maclennan, Joseph E.,Glaser, Matt A.,Clark, Noel A.,Walba, David M.
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p. 430 - 438
(2017/05/26)
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- Preparation method of 4-acetamidoanisole
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The invention discloses a preparation method of 4-acetamidoanisole. The preparation method comprises the following step: performing an acetylation reaction on acetic anhydride and a compound as shown in a formula 3 to obtain a compound as shown in a formula 4, wherein the acetylation reaction is performed in the absence of glacial acetic acid. The preparation method is low in pollution, low in cost, short in reaction time, low in reaction temperature and mild in reaction condition.
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Paragraph 0023; 0044-0046
(2017/11/04)
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- Preparation method of P-aminoanisole
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The invention discloses a preparation method of P-aminoanisole. The method comprises the following step: performing a reduction reaction shown as follows on a compound shown in the formula 2 and hydrogen under the action of a catalyst Pd/C, so as to obtai
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Paragraph 0040; 0041
(2017/11/04)
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- Preparation method of 2-methoxy-5-acetamidoaniline
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The invention discloses a preparation method of 2-methoxy-5-acetamidoaniline. The preparation method comprises the following step: in a solvent, under the action of a catalyst Pd/C, performing a reduction reaction as shown below on a compound as shown in a formula 5 and hydrogen to obtain a compound as shown in a formula 6. The preparation method is low in pollution, high in yield rate, low in cost, convenient in catalyst or solvent recycling, short in reaction time, low in reaction temperature, high in safety and mild in reaction condition.
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Paragraph 0086; 0087
(2017/11/04)
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- Preparation method of 2-nitro-4-acetamidoanisole
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The invention discloses a preparation method of 2-nitro-4-acetamidoanisole. The preparation method comprises the following step: under the action of concentrated sulfuric acid, performing nitration reaction as shown below on a compound as shown in a formula 4 and an aqueous nitric acid solution having the mass fraction of 30-80% to obtain a compound as shown in a formula 5, wherein the percent of the 30-80% aqueous nitric acid solution is the mass percent of the nitric acid in the aqueous nitric acid solution. The preparation method is high in safety, free of special equipment requirement and environment-friendly, and is suitable for industrial production.
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Paragraph 0056-0057; 0060; 0061; 0065; 0067
(2017/11/04)
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- Methoxylation and Direct Hydrogenative Coupling of Chloronitrobenzenes in Continuous Flow
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A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxybenzenes were obtained from the corresponding nitrobenzenes in the presence of NaOH in continuous flow. Compared to batch conditions, the reaction time was significantly shortened, and the chemical waste was reduced obviously.
- Shi, Songjie,Wan, Li,Sun, Xiaoning,Zhang, Jiawei,Guo, Kai
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p. 410 - 414
(2017/04/27)
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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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- Nucleophilic deoxyfluorination of phenols via aryl fluorosulfonate intermediates
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This report describes a method for the deoxyfluorination of phenols with sulfuryl fluoride (SO2F2) and tetramethylammonium fluoride (NMe4F) via aryl fluorosulfonate (ArOFs) intermediates. We first demonstrate that the reaction of ArOFs with NMe4F proceeds under mild conditions (often at room temperature) to afford a broad range of electronically diverse and functional group-rich aryl fluoride products. This transformation was then translated to a one-pot conversion of phenols to aryl fluorides using the combination of SO2F2 and NMe4F. Ab initio calculations suggest that carbon-fluorine bond formation proceeds via a concerted transition state rather than a discrete Meisenheimer intermediate.
- Schimler, Sydonie D.,Cismesia, Megan A.,Hanley, Patrick S.,Froese, Robert D.J.,Jansma, Matthew J.,Bland, Douglas C.,Sanford, Melanie S.
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p. 1452 - 1455
(2017/02/10)
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