Reactions Of Aromatic Compounds Research Articles

AI2O3/MeSO3H (AMA) as a Novel Heterogeneous System for the Nitration of Aromatic Compounds by Magnesium Nitrate Hexahydrate

Mg(NO3)2.6H2O was an efficient nitrating agent in the presence of a mixture of AI2O3/MeSO3H (AMA) as a novel heterogeneous system for the nitration of aromatic compounds without use of any organic solvents and with high selectivity. The reaction proceeds at room temperature for the nitration of highly reactive aromatic compounds such as phenols and anilines.

A condensed-to-atom nucleophilicity index. An application to the director effects on the electrophilic aromatic substitutions

The local nucleophilicity of simple substituted aromatic systems is shown to be described on a quantitative basis by using a condensed-to-atoms nucleophilicity index. This quantity constitutes an extension of the global nucleophilicity descriptor, N introduced for reagents in cycloaddition reactions and other organic molecules [Journal of Organic Chemistry 73 (2008) 4615–4624; Journal of Molecular Structure (THEOCHEM) 865 (2008) 68–72]. The local projection N k is performed on the basis of the normalization condition of the Fukui functions. It is shown that such a simple index provides useful clues about the director effects of the substituents on the electrophilic aromatic substitution (EAS) reactions of aromatic compounds. A discussion of the general frame of validity for the condensed-to-atoms model is presented.

Practical Electrochemical Iodination of Aromatic Compounds

A practical method for electrochemical iodination of aromatic compounds was developed. The method involves the generation of I+ by electrochemical oxidation of I2 in CH3CN using H2SO4 as supporting electrolyte followed by the reaction with aromatic compounds. The para/ortho selectivity for the reaction of monosubstituted benzenes was significantly improved using dimethoxyethane as cosolvent in the second step. The reaction with highly reactive aromatic compounds led to the formation of significant amounts of diiodo compounds in a macrobatch reactor. This problem was solved by fast 1:1 mixing of I+ with an aromatic compound using a microflow system consisting of a T-shaped micromixer and a microtube reactor.

Pyridinium Iodochloride: An Efficient Reagent for Iodination of Hydroxylated Aromatic Ketones and Aldehydes

AbstractDirect iodination of several reactive aromatic compounds like hydroxy substituted acetophenones and aldehydes with pyridinium iodochloride (PyICl) proceeded smoothly to afford the corresponding aromatic iodides in good to excellent yield. Pyridinium iodochloride has been found to be an efficient solid iodinating reagent with no hazardous effect and it can be handled safely.

Quantum-chemical interpretation of the effect of substitution in the benzene ring on the reactivity of monosubstituted benzenes

The HF/3-21G and HF/6-31G** methods were used to calculate the effective charges on the carbon and hydrogen atoms in the meta and para positions of the aromatic ring in monosubstituted benzenes. The calculated charges are compared with the Hammett constants of the substituents in the aromatic ring. Linear correlations were obtained between the atomic charges and the Hammett constants of the substituents. The resulting equations were shown to be useful for predicting and assessing the reactivity of aromatic compounds.

Blanc Reaction of Aromatic Compounds Catalyzed by Ionic Liquids

Ionic liquids have been used as catalysts for Blanc reaction of toluene. The effects of reaction temperature, reaction time and dosage of the ionic liquid catalyst have been investigated, and the catalytic performance of different ionic liquid catalysts for toluene chloromethylation was also studied. The reaction was found to proceed under mild conditions with excellent conversion (up to 90%) in the absence of Lewis acids. The ionic liquids could be recycled and reused without loss of their catalytic activities.

Orthoamide, LXVII [1]. Bis(diformylamino)methan – ein neues leistungsfähiges Formylierungsmittel für aromatische Verbindungen / Orthoamides, LXVII [1]. Bis(diformylamino)methane – a New Efficient Formylating Reagent for Aromatic Compounds

Abstract Formaldehyde reacts with diformamide (10) to give N-(hydroxymethyl)diformamide (11), which upon treatment with thionylchloride yields N-(chlormethyl)diformamide (12) together with small amounts of oxydimethylenebis(diformamide) (13). Various diformylamine derivatives, such as diformylaminomethyl formiate (14), diformylaminomethylisothiocyanate (15) and the N-diformylaminomethylated guanidinium salt 16, can be prepared from 12. Bis(diformylamino) methane (7) can be obtained by the reaction of sodium diformamide (8) with either 1-(chloromethyl)pyridinium chloride (9) or N-(chloromethyl)diformamide (12) in acetonitrile. The action of tris(chloromethyl) amine (18) on sodium diformamide (8) affords tris(diformylaminomethyl)amine (19). The constitution of the compounds 7, 11 and 19 was confirmed by crystal structure determination. The nature of the products from the reactions of aromatic compounds with 12 depends on the Lewis acid which is used as activator. Thus the N-benzylformamides 20a, b can be obtained from toluene and mesitylene and 12/BF3-ether, whereas 1,2,4-trimethoxybenzene is formylated by 12/AlCl3 to give the aldehyde 22. Interestingly enough, a novel and efficient formylating reagent resulted from these investigations: bis(diformylamino)methane (7), which can be activated by Lewis acids, e. g. AlCl3. The scope of this procedure is comparable with that of the Olah-formylation method (formylfluoride/BF3).

Uma metodologia simples e eficiente para a cloração de compostos aromáticos ativados utilizando o ácido tricloro-isocianúrico

The chlorination of activated aromatic rings is efficiently achieved under mild conditions by reaction of aromatic compounds with trichloroisocyanuric acid in acetonitrile, at room temperature, leading to products in 60-95% isolated yields and good regioselectivity.

Reprocessing of spent solvent of the UNEX process

A procedure was developed for conversion of spent UNEX solvent into a solid infusible resin, insoluble in aqueous alkali and acid solutions and organic solvents, by condensation with phenol and paraform. Incorporation of phenyl trifluoromethyl sulfone into the resin was confirmed by physicochemical methods. Resistance of the cured resin to high temperatures was proved by thermogravimetry. The developed procedure can also be applied to other organic wastes containing weakly reactive aromatic compounds such as nitrobenzotrifluoride, 1,2-dichlorobenzene, and nitrobenzene.

Predicting arene rate coefficients with respect to hydroxyl and other free radicals in the gas-phase: a simple and effective method using a single topological descriptor

Abstract. The reactivity of aromatic compounds is of great relevance to pure and applied chemical disciplines, yet existing methods for estimating gas-phase rate coefficients for their reactions with free radicals lack accuracy and universality. Here a novel approach is taken, whereby strong relationships between rate coefficients of aromatic hydrocarbons and a Randić-type topological index are investigated, optimized and developed into a method which requires no specialist software or computing power. Measured gas-phase rate coefficients for the reaction of aromatic hydrocarbons with OH radicals were correlated with a calculated Randić-type index, and optimized by including a term for side chain length. Although this method is exclusively for use with hydrocarbons, it is more diverse than any single existing methodology since it incorporates alkenylbenzenes into correlations, and can be extended towards other radical species such as O(3P) (and tentatively NO3, H and Cl). A comparison (with species common to both techniques) is made between the topological approach advocated here and a popular approach based on electrophilic subsituent constants, where it compares favourably. A modelling study was carried out to assess the impact of using estimated rate coefficients as opposed to measured data in an atmospheric model. The difference in model output was negligible for a range of NOx concentrations, which implies that this method has utility in complex chemical models. Strong relationships (e.g. for OH, R2=0.96) between seemingly diverse compounds including benzene, multisubstituted benzenes with saturated, unsaturated, aliphatic and cyclic substitutions and the nonbenzenoid aromatic, azulene suggests that the Randić-type index presented here represents a new and effective way of describing aromatic reactivity, based on a quantitative structure-activity relationship (QSAR).

JIRO TSUJI. Palladium reagents and catalysts: new perspectives for the 21st century. Wiley–VCH, 2004. 670 pp. ISBN 0470850337 (paperback)

JIRO TSUJI. Palladium reagents and catalysts: new perspectives for the 21st century. Wiley–VCH, 2004. 670 pp. ISBN 0470850337 (paperback)

Ytterbium Triflate Catalyzed Friedel–Crafts Reaction: Facile Synthesis of Diaryl Ketones

Friedel–Crafts reaction of aromatic compounds (benzenes, thiophene, furan, pyrrole, naphthalene, and benzothiophene) with bis(trichloromethyl) carbonate [BTC] was efficiently catalyzed by ytterbium triflate [Yb(OTf)3] to give diaryl ketones with moderate to good yields.

Halex Reactions of Aromatic Compounds Catalyzed by 2‐Azaallenium, Carbophosphazenium, Aminophosphonium and Diphosphazenium Salts: A Comparative Study.

AbstractFor Abstract see ChemInform Abstract in Full Text.

In(OTf)3-Catalyzed Friedel-Crafts Reaction of Aromatic Compounds with Methyl Trifluoropyruvate in Water

In the presence of In(OTf) 3 as a catalyst, aniline derivatives la-c, 1e-h and anisole derivatives 2a-c, 2e reacted with methyl trifluoropyruvate 3 in water at room temperature to give the corresponding Friedel-Crafts reaction products 4a-g and 5a-d in good yields, respectively.

Electron‐Transfer Reactions of Aromatic Compounds

AbstractFor Abstract see ChemInform Abstract in Full Text.

ChemInform Abstract: Aromatic Benzenoids. Part 3. Reactions of Aromatic Compounds

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleophilic Addition Reaction of Aromatic Compounds in the Presence of Lewis Acid

The epoxide 1 obtained by the Darzens condensation reaction of aldehydes with methyl dichloroacetate, reacted with aromatic compounds in the presence of aluminium chloride to afford α-aryl- -chloro-α-hydroxyalkanoate 3. Scope and limitation of this reaction were studied for various aldehydes and aromatic compounds. The reaction was also studied in the presence of aluminium chloride supported on alumina or silica gel, which is thought to be a mild Lewis acid and harmless for the environment.

ChemInform Abstract: Reactions of Aromatic Compounds with Nucleophilic Reagents in Liquid Ammonia. Part 17. Effect of Ionic Association on the Orientation in Aryloxydefluorination of 2,4‐Difluoronitrobenzene.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Two-Photon Photochemical Reactions of Aromatic Compounds in the Gas Phase

Studies on the gas-phase two-photon photochemistry of aromatic compounds performed in the past 25 years were summarized. Photophysical and photochemical unimolecular and bimolecular reactions occurring in the gas phase on the exposure of molecular systems (aliphatic aldehydes, ketones, and alcohols; aromatic hydrocarbons and their halogen derivatives; and heteroaromatic compounds with a conjugated π-electron system) to pulsed laser UV radiation were considered. Data on the kinetics and mechanisms of primary two-photon photoexcitation, photodissociation, and photoionization of aromatic molecules were systematized, and the nature of electronically excited states responsible for these processes was determined. Data on the reactivity of transient species and on the kinetics of elementary steps of laser UV photolysis (bimolecular charge transfer and heavy particle transfer reactions and termolecular association and cluster ion formation reactions) were presented. General prerequisites to the stability of aromatic compounds under non-steady-state conditions of UV photolysis were found in accordance with the electronic structure of reactants and with the donor–acceptor properties of mixture components.

Reactions of aromatic compounds with nucleophilic reagents in liquid ammonia: XVII. Effect of ionic association on the orientation in aryloxydefluorination of 2,4-difluoronitrobenzene

The analysis of dependence of fluorine replacement orientation in 2,4-difluoronitrobenzene effected by nucleophiles Y-C6H4OM (Y =p-OMe,p-Me,m-Me, H,p-F,p-Cl,m-F,m-Cl; M = Li, Na, K, Et4N, Bu4N) in liquid ammonia medium at -35‡C on the nature of M, Y, on nucleophile concentration, on addition of crown ethers, diaminoalkanes, and dimethoxyethane indicates the occurrence of ionic association at M = K, Na.