- Simple preparation of high-quality graphene flakes without oxidation using potassium salts
-
Preparation of graphene flakes without oxidation is important to preserve the superb intrinsic properties of graphene. A new and simple route to produce few-layer, flake-type graphene with minimized oxidation (2%) by the intercalation of potassium into raw graphite using potassium salts is proposed. Copyright
- Kwon, Jiyoung,Lee, Sun Hwa,Park, Kwang-Hyun,Seo, Dong-Hwa,Lee, Jinsup,Kong, Byung-Seon,Kang, Kisuk,Jeon, Seokwoo
-
-
Read Online
- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
-
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
-
p. 18040 - 18049
(2021/05/29)
-
- Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
-
We herein report Cu mediated side-directed dehydroxyalkylative halogenation of aryl alcohols. C(aryl)-C bonds of aryl alcohols were effectively cleaved, affording the corresponding aryl chlorides, bromides and iodides in excellent yields. Aryl alcohols could serve as both aromatic electrophilic and radical synthetic equivalents during the reaction.
- Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
-
supporting information
p. 7120 - 7123
(2020/07/14)
-
- Arene diazonium saccharin intermediates: A greener and cost-effective alternative method for the preparation of aryl iodide
-
In the current protocol, the arene diazonium saccharin derivatives were initially produced from various substituted aromatic amines; subsequently, these intermediates were treated with a greener organic iodide for the preparation of the aryl iodide. We tried to choose low-cost, commercially available, biodegradable, recoverable, ecofriendly, and safe reagents and solvents. The arene diazonium saccharin intermediates could be stored in the liquid phase into a refrigerator for a long time with no significant loss activity. The outstanding merits of the current protocol (a) included the partial recovering of saccharin and tetraethylammonium salt, (b) reduce the use of solvents and the reaction steps due to eliminating separation and purification of intermediates, (c) good yield of the sterically hindered substrates, and (d) avoid the generation of heavy metal or corrosive waste.
- Ghaffari Khaligh, Nader,Rafie Johan, Mohd,Shahnavaz, Zohreh,Zaharani, Lia
-
p. 535 - 542
(2020/06/01)
-
- Functional Group Transposition: A Palladium-Catalyzed Metathesis of Ar-X σ-Bonds and Acid Chloride Synthesis
-
We describe the development of a new method to use palladium catalysis to form functionalized aromatics: via the metathesis of covalent σ-bonds between Ar-X fragments. This transformation demonstrates the dynamic nature of palladium-based oxidative addition/reductive elimination and offers a straightforward approach to incorporate reactive functional groups into aryl halides through exchange reactions. The reaction has been exploited to assemble acid chlorides without the use of high energy halogenating or toxic reagents and, instead, via the metathesis of aryl iodides with other acid chlorides.
- De La Higuera Macias, Maximiliano,Arndtsen, Bruce A.
-
supporting information
p. 10140 - 10144
(2018/08/23)
-
- A facile and sustainable protocol to the preparation of aryl iodides using stable arenediazonium bis(trifluoromethylsulfonyl)imide salts via the telescopic process
-
The preparation of aryl iodides in a telescopic reaction using tert-butyl nitrite as a diazotization reagent and a mixture of bis(trifluoromethane) sulfonamide and glacial acetic acid as a mild acidic agent in ethanol followed by iododediazoniation with tetraethylammonium iodide in water was investigated. The current method has other advantages such as minimized waste by avoiding solvent for the purification of products in diazotization step, simple experimental procedure, and good yield of the sterically hindered aryl amines, metal and strong acid-free waste and environmentally benign conditions. The noteworthy features of this study are the preparation of stable arenediazonium bis(trifluoromethylsulfonyl)imide salts that can be used with no significant loss activity after 1?week and bis(trifluoromethane)sulfonamide was recovered in high yields from reactions.
- Khaligh, Nader Ghaffari
-
-
- Visible-Light-Induced Decarboxylative Iodination of Aromatic Carboxylic Acids
-
A convenient, efficient and practical visible-light-induced decarboxylative iodination of aromatic carboxylic acids has been developed, and the corresponding aryl iodides were obtained in good yields. The method shows some advantages including the use of readily available aromatic carboxylic acids as the starting materials, simple and mild conditions, high efficiency, wide substrate scope and tolerance of various functional groups.
- Jiang, Min,Yang, Haijun,Jin, Yunhe,Ou, Lunyu,Fu, Hua
-
supporting information
p. 1572 - 1577
(2018/06/26)
-
- An efficient gram scale synthesis of aryl iodides from aryl diazofluoroborates in water under mild conditions
-
Transition metal-free synthesis of synthetically valuable aryl iodides from aryl diazofluroborates in water under mild conditions has been described. Majority of synthesized aryl iodides are obtained in quantitative yields (>99%) under present reaction conditions. The structural effects due to the substituents present on aryl diazofluoroborates did not show any satisfactory effect on the yields of the aryl iodides. Hence, the methodology presented here was found to be adventitious for the quantitative production of synthetically valuable aryl iodides.
- Gholap, Somnath S.
-
p. 594 - 599
(2018/06/26)
-
- Eco-compatible zeolite-catalysed continuous halogenation of aromatics
-
A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (>95%) of iodobenzene with nearly 100 kg iodobenzene converted per kgcat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-?BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structure-activity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized ?BEA zeolites and more specifically nanosponge-like ?BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-?BEA zeolites.
- Losch,Kolb,Astafan,Daou,Pinard,Pale,Louis
-
supporting information
p. 4714 - 4724
(2016/09/04)
-
- Metal-free iodination of arylboronic acids and the synthesis of biaryl derivatives
-
A simple, general and efficient method is developed for the metal-free iodination of arylboronic acids. The protocol uses very cheap molecular iodine as the halide source and potassium carbonate as the base. The method is highly tolerant of various functional groups present in the substrates. Importantly, the iodination strategy can also be applied very effectively in the one-pot, two-step synthesis of biaryl derivatives. Georg Thieme Verlag Stuttgart New York.
- Niu, Liting,Zhang, Hao,Yang, Haijun,Fu, Hua
-
supporting information
p. 995 - 1000
(2014/05/06)
-
- Nitrite ionic liquid as a new reagent for in situ synthesis of aryl iodides and azides
-
A new ionic liquid, 1-methyl-3-(2-[2-(1-methyl-1H-imidazol-3-ium-3-yl)ethyloxy] ethyl)-1H-imidazol-3-ium dinitrite, was synthesized. This ionic liquid was used as a convenient nitrosonium source in diazotization of aryl amines into their corresponding diazonium salts, which were converted into aryl iodides and aryl azides using potassium iodide or sodium azide, respectively. Various aryl amines possessing electron-withdrawing groups or electron-donating groups were converted into the corresponding aryl iodides and aryl azides in excellent yields. Advantages of this methodology are the use of mild reaction conditions, short reaction times, and avoiding the use of toxic solvents.
- Eshghi, Hossein,Bakavoli, Mehdi,Ghasemzadeh, Marjan
-
p. 3999 - 4007
(2015/06/08)
-
- Tetraflic acid (1,1,2,2-Tetrafluoroethanesulfonic acid, HC 2F4SO3H) and gallium tetraflate as effective catalysts in organic synthesis
-
Tetraflic acid offers ample acidity for various organic reactions that require high acidity. Its gallium(III) salt is an efficient catalyst under mild condtions for synthetic transformations such as the ketonic Strecker reaction for the synthesis of fluorinated α-amino nitriles and condensation- cyclzation reactions using suitable fluoro ketones and 1,2-disubstituted benzenes for the direct preparation of 5-membered or 6-membered fluorinated heterocycles. Copyright
- Prakash, G. K. Surya,Mathew, Thomas,Panja, Chiradeep,Kulkarni, Aditya,Olah, George A.,Harmer, Mark A.
-
p. 2163 - 2171
(2012/11/07)
-
- Potassium 4-iodylbenzenesulfonate: Preparation, structure, and application as a reagent for oxidative iodination of arenes
-
A new hypervalent iodine(V) compound, potassium 4-iodylbenzenesulfonate, was prepared by the oxidation of 4-iodobenzensulfonic acid with Oxone in water. This potassium salt can be further converted into 4-iodylbenzenesulfonic acid by treatment with the acidic form of Amberlyst 15 in water. A single-crystal X-ray structure of potassium 4-iodylbenzenesulfonate revealed the presence of polymeric chains in the solid state due to a combination of numerous intra- and intermolecular interactions. Potassium 4-iodylbenzenesulfonate will likely find many practical applications as a thermally stable and water-soluble hypervalent iodine-based oxidant, particularly useful as a reagent for oxidative iodination of aromatic substrates. This reagent can be effectively recovered from the reaction mixture (92 % recovery) by treatment of the aqueous layer with Oxone at 60°C for 2 h, followed by filtration of the precipitate. A new hypervalent iodine(V) compound, potassium 4-iodylbenzenesulfonate, was prepared by oxidation of 4-iodobenzenesulfonic acid with Oxone in water. This new reagent promises many practical applications as a thermally stable, water-soluble and recyclable hypervalent iodine oxidant, particularly useful for oxidative iodination of aromatic substrates.
- Yusubov, Mekhman S.,Yusubova, Roza Y.,Nemykin, Victor N.,Maskaev, Andrey V.,Geraskina, Margarita R.,Kirschning, Andreas,Zhdankin, Viktor V.
-
p. 5935 - 5942,8
(2020/09/02)
-
- Superelectrophilic iodination of deactivated arenes with triiodoisocyanuric acid
-
The reaction of triiodoisocyanuric acid (TICA) with deactivated arenes in acidic medium led to the efficient and regioselective formation of the corresponding iodoarenes, in 55-88% isolated yield. The acidity of the medium was found to be the most important factor influencing the electrophilic iodination of weakly nucleophilic substrates by TICA. Georg Thieme Verlag Stuttgart New York.
- Da Ribeiro, Rodrigo S.,Esteves, Pierre M.,De Mattos, Marcio C. S.
-
experimental part
p. 739 - 744
(2011/04/24)
-
- Metal-free efficient, general and facile iododecarboxylation method with biodegradable co-products
-
The development of a novel, efficient and robust method for the general conversion of aliphatic and aromatic carboxylic acids to organic iodides without the use of heavy metals or strong oxidizing agents is reported. Commercially available N-iodoamides were used for both initiation and halogen donation under irradiative conditions. Isolation of the product is extremely simple and the major co-product is removed as a water-soluble biodegradable material. Copyright
- Kulbitski, Kseniya,Nisnevich, Gennady,Gandelman, Mark
-
supporting information; experimental part
p. 1438 - 1442
(2011/07/30)
-
- PROCESS FOR THE PREPARATION OF IODIDES
-
This invention is directed to a process for the preparation of high yield alkyl or aryl iodide from its corresponding carboxylic acid using N-iodo amides.
- -
-
Page/Page column 33-34
(2012/01/05)
-
- 2-Chlorophenyl zinc bromide: A convenient nucleophile for the mannich-related multicomponent synthesis of clopidogrel and ticlopidine
-
A methodological study devoted to the Mannich-like multicomponent synthesis of the antiplatelet agent (±)-clopidogrel (7) and the ethyl ester analogue 6 is described. The process involves the formation of 2-chlorophenyl zinc bromide (2) and its subsequent reaction with an alkyl glyoxylate and 4,5,6,7-tetrahydrothieno[3,2-c]pyridine (3). We demonstrate that the organozinc reagent 2 also constitutes a very convenient nucleophile for the multicomponent synthesis of the benzylamine core of ticlopidine (9).
- Isabelle, Aillaud,Haurena, Caroline,Gall, Erwan Le,Martens, Thierry,Ricci, Gino
-
experimental part
p. 8144 - 8155
(2011/02/27)
-
- METHOD OF PRODUCING IODIZING AGENT, AND METHOD OF PRODUCING AROMATIC IODINE COMPOUND
-
A method of the present invention, for producing an iodizing agent, includes the step of electrolyzing iodine molecules in a solution by using an acid as a supporting electrolyte. This realizes (i) a method of producing an iodine cation suitable for use as an iodizing agent that does not require a sophisticated separation operation after iodizing reaction is completed, and (ii) an electrolyte used in the method. Further, a method of the present invention, for producing an aromatic iodine compound, includes the step of causing an iodizing agent, and an aromatic compound whose nucleus has one or more substituent groups and two or more hydrogen atoms, to react with each other under the presence of a certain ether compound. This realizes such a method of producing an aromatic iodine compound that position selectivity in iodizing reaction of an aromatic compound is improved.
- -
-
Page/Page column 11
(2010/05/13)
-
- Direct synthesis of iodoarenes from aromatic substrates using molecular iodine
-
Easy laboratory procedures for oxidative iodination of aromatic substrates are presented. One procedure includes the iodination using molecular iodine, concentrated sulfuric acid, and potassium peroxodisulfate, and another uses a reagent system containing molecular iodine, potassium peroxodisulfate, and trifluoroacetic acid. These procedures are especially effective for benzene and less deactivated aromatic substrates, such as halobenzenes, trifluoromethylbenzene, and benzoic acid. Georg Thieme Verlag Stuttgart.
- Hossain, Md. Delwar,Oyamada, Juzo,Kitamura, Tsugio
-
p. 690 - 692
(2008/09/21)
-
- Method for separating substances
-
An objective of the present invention is to provide electrophoretic separation methods and devices that enable the various features of a substrate surface that comes in contact with an electrophoresis medium to be controlled. The present invention provides methods for electrophoresing substances, which comprises the steps of: (a) adding a substance to be analyzed to an electrophoresis medium retained in a substrate, whose surface that has come in contact with the electrophoresis medium has been coated with a polymer membrane; and (b) adding electrophoretic pressure to the electrophoresis medium. For example, the use of a plasma-polymerized membrane allows the formation of a membrane with homogeneous quality and thickness on the surface of an arbitrary shape. In addition, desired characteristics can be conferred on the surface through selection of monomeric substances. Protein adsorption onto micro-chips can be effectively prevented as well.
- -
-
-
- N-halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
-
N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. Because BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H0 ≈ 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF3-H2O has been developed. DFT calculations at the B3LYP/6-311++G**//B3LYP/6-31G* level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X+ from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X+ which would readily react with the aromatic substrates. Structural aspects of the BF 3-H2O complex have also been investigated.
- Prakash, G. K. Surya,Mathew, Thomas,Hoole, Dushyanthi,Esteves, Pierre M.,Wang, Qi,Rasul, Golam,Olah, George A.
-
p. 15770 - 15776
(2007/10/03)
-
- An Efficient, Catalytic, Aerobic, Oxidative Iodination of Arenes Using the H5PV2Mo10O40 Polyoxometalate as Catalyst
-
Iodination of arenes was carried out by reacting 1 equiv of arene substrate with 0.5 equiv of iodine under an oxygen atmosphere with H 5PV2Mo10O40 as oxidation catalyst. The synthesis is an inherently waste-free method for the preparation of iodoarenes.
- Branytska, Olena V.,Neumann, Ronny
-
p. 9510 - 9512
(2007/10/03)
-
- Nitrogen dioxide - Sodium iodide as an efficient reagent for the one- pot conversion of aryl amines to aryl iodides under nonaqueous conditions
-
Successive treatment of aromatic amines with liquid nitrogen dioxide and powdered sodium iodide in acetonitrile at -20 °C, followed by usual work- up, gave the corresponding aryl iodides in good yield. This method worked especially well for less basic amines bearing electron-withdrawing substituents.
- Suzuki, Hitomi,Nonoyama, Nobuaki
-
p. 4533 - 4536
(2007/10/03)
-
- Oxidative Anion Metatheses in Diaryliodonium Iodides and Chlorides
-
Oxidative anion metatheses in the crude title iodides and chlorides produced the corresponding pure hydrogensulfates, nitrates, tetrafluoroborates, triflates, tosylates, as well as bromides and chlorides (only from the iodides) in 54-86% yields. These procedures are easier and shorter than earlier methods. By using modified oxidative metatheses in the title iodides (in the presence of HBr or HCl) it was possible either to isolate, or to detect only, the intermediate dihaloiodates(I). [Ar2I]+[IX2]- (X = Br or Cl). A complex Ph2I+Cl- -1/2I2 was also obtained in 56% yield. Tetraethylammonium iodide was similarly converted into pure tetrafluoroborate or dibromoiodate(I) in 75 and 76% yields, respectively.
- Kazmierczak, Pawel,Skulski, Lech
-
p. 219 - 224
(2007/10/03)
-
- Aromatic iodination with the I2-HgX2 combination
-
The reaction of differnt aromatic compounds 1a-1t with iodine and a mercury(II)-salt 2 [mercury(II) chloride, nitrate or triflate] (1:1:1 molar ratio) in dichloromethane at room temperature leads to the corresponding iodoarene 3, the obtained regiochemistry being the expected. Concerning the mercury(II) salt, the observed reactivity decreased in the series triflate > nitrate > chloride according to their ionic character. An activation of the iodine molecule by the mercury(II) salt followed by a S(E) reaction with the aromatic compounds is postulated as the possible mechanism.
- Bachki, Abderrazak,Foubelo, Francisco,Yus, Miguel
-
p. 5139 - 5146
(2007/10/02)
-
- An Expeditious and General Aromatic Iodination Procedure
-
The reaction of IPy2BF4 with an arene and an acid (HBF4 or CF3SO3H), in CH2Cl2 at room temperature, provides a mild and efficient entry to the preparation of iodinated arenes.
- Barluenga, Jose,Gonzalez, Jose M.,Garcia-Martin, Miguel A.,Campos, Pedro J.,Asensio, Gregorio
-
p. 1016 - 1017
(2007/10/02)
-
- ONE STEP CONVERSION OF ANILINES TO ARYL HALIDES USING SODIUM NITRITE AND HALOTRIMETHYLSILANE
-
Anilines were easily diazotized and efficiently converted to aryl halides in an one-pot reaction using sodium nitrite and halotrimethylsilane in carbon tetrachloride.Halotrimethylsilanes are used for both generating nitrosonium donor from sodium nitrite, and the halogen substitution of diazonium group.
- Lee, Jong Gun,Cha, Hee Tae
-
p. 3167 - 3168
(2007/10/02)
-
- STOICHIOMETRIC AND CATALYTIC OXIDATIVE IODINATION OF AROMATIC COMPOUNDS IN THE PRESENCE OF NITROGEN-CONTAINING OXIDIZING AGENTS IN AQUEOUS TRIFLUOROACETIC ACID
-
The conditions for oxidative monoiodination of benzene, halogenobenzenes, toluene, halogenotoluenes, and p-toluic acid in solvents based on trifluoroacetic acid were studied.Yields of the respective iodoarenes close to quantitative were obtained in systems containing 10-20 vol. percent of water in the solvent with equimolar amounts of alkali-metal metal iodides in relation to the substrate in the presence of stoichiometric (under anaerobic conditions) or catalytic (in the presence of oxygen or air) amounts of alkali-metal nitrates.The analogous reactions with nitrites can only be conducted under aerobic conditions.These iodinating systems are compared with systems based on acetic acid containing iodine and mixtures of sulfuric and nitric acids.The conditions for the iodination of toluene and for the transformations of the obtained iodotoluenes in the presence of nitrogen-containing oxidizing agents in trifluoroacetic acid solutions were studied in detail.It was shown that p-iodotoluene undergoes ipso-nitrodeiodination to a significant degree under these conditions.It is supposed that the iodinating agent in the investigated systems is trifluoroacetyl hypoiodite.Data on the assignment of the PMR spectra of the synthesized isomeric nitroiodotoluenes and chloroiodotoluenes by a simple additive method are given.
- Makhon'kov, D. I.,Cheprakov, A. V.,Beletskaya, I. P.
-
p. 2029 - 2035
(2007/10/02)
-
- OXIDATIVE CHLORINATION OF AROMATIC COMPOUNDS IN THE PRESENCE OF NITROGEN-CONTAINING OXIDIZING AGENTS
-
Mixture of the chlorides and nitrates of alkali metals in aqueous trifluoroacetic acid can be used for the selective oxidative chlorination of benzene, halogenobenzenes, toluene, and p-toluic acid with preparative yields.By variation of the water content of the solvent and the nitrate-chloride ratio it is possible to suppress the nitration side reaction.In the presence of oxygen or air alkali-metal nitrites can also be used as oxidizing agents in this process.The chlorinating agent in these systems is molecular chlorine, as confirmed by a comparative study of the reactions of two groups of potential chlorinating agents (nitrosyl chloride and nitryl chloride) under these conditions.The reactions of naphthalene and polymethylbenzenes with nitrosyl chloride in trifluoroacetic acid, leading to the products from chlorination and dehydrooligomerization of the aromatic substrates, were also studied.
- Makhon'kov, D. I.,Cheprakov, A. V.,Rodkin, M. A.,Beletskaya, I. P.
-
p. 211 - 217
(2007/10/02)
-
- Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K
-
The reactions of hydroxyl radicals with benzene derivates C6H5Z (Z = H, Me, F, Cl, Br, I, CF3, or CN) have been studied in a flow reactor at 563 K in nitrogen, using the thermolysis of ButOOH as a source of .OH.Under these conditions there are two product-forming pathways.The major one involves hydrogen abstraction to give aryl radicals ZC6H4. (II) as the first step; depending on Z, its displacement to form phenol may also occur.Relative rates for hydrogen abstraction were determined in competition experiments using side-chain hydrogen abstraction from added toluene as a reference.This resulted in the order (for Z =): 1,8(Me), 1.0(H), 0.47(F), 0.29(Cl), 0.34(CF3), 0.20(CN), consonant with the electrophilic nature of .OH.The site selectivity of hydrogen abstractions was determined by scavenging part of the aryl radicals (II) with iodine.A Hammett plot, using ? constants for meta and para positions, led to ρ -1.0.The features of hydrogen abstraction by .OH are discussed and compared with those for the analogous reaction of Cl.The formation of phenol was found to decrease in importance in the order F, Cl, Br, and I.This result is rationalized on a thermochemical kinetic basis.
- Mulder, Peter,Louw, Robert
-
p. 1167 - 1174
(2007/10/02)
-
- OXIDATION BY THE SALTS OF METALS. VI. OXIDATIVE IODINATION OF AROMATIC SUBSTRATES, PROMOTED BY Co(III), Mn(III), AND Ce(IV) COMPOUNDS IN AQUEOUS TRIFLUOROACETIC ACID
-
The direct iodination of benzene, halogenobenzenes, and p-methoxycarbonyltoluene in trifluoroacetic acid and its aqueous solutions with iodine or alkali-metal iodides was studied in the presence of Co(III) and Mn(III) acetates and ammonium cerium(IV) sulfate, which make it possible to obtain the respective iodoarenes with high yields under mild conditions.In the case of toluene the reaction is complicated by the formation of α-oxidation products.It is assumed that the iodinating agent is trifluoroacetyl hypoiodite, formed as a result of the oxidation of the iodine by the salt of the metal having variable valence.The highest yields of the iodoarenes were obtained with 90percent aqueous trifluoroacetic acid.
- Makhon'kov, D. I.,Cheprakov, A. V.,Rodkin, M. A.,Beletskaya, I. P.
-
p. 1003 - 1006
(2007/10/02)
-
- OXIDATION BY METAL SALTS. OXIDATIVE HALOGENATION OF BENZENE AND HALOBENZENES PROMOTED BY Co(III) AND Mn(III) ACETATES IN TRIFLUOROACETIC ACID AND ITS AQUEOUS SOLUTIONS
-
A study was carried out on the oxidation of benzene and halobenzenes by Co(III) and Mn(III) acetates in the presence of alkali metal chlorides and bromides in CF3CO2H and its aqueous solutions (10-33 vol. percent H2O).The optimal water content in the solution is a function both of the nature of the metal oxidizing agent and the aromatic substrate.The reaction presumably proceeds through the formation of an aromatic radical-cation which then reacts with the halide anion.The oxidative chlorination of bromobenzene is complicated by ipso substitution and bromine redistribution.Phenyl iodosodichloride may be isolated in preparative yield in the chlorination of iodobenzene.In other cases, variation of the reaction conditions may give high yields of the corresponding chlorine and bromine derivatives.The feasibility of polychlorination was studied.Possible reaction mechanisms were considered.
- Makhon'kov, D. I.,Cheprakov, A. V.,Beletskaya, I. P.
-
p. 609 - 615
(2007/10/02)
-
- OXIDATION BY THE SALTS OF METALS. VII. PLUMBATION AND OXIDATIVE SUBSTITUTION OF AROMATIC COMPOUNDS IN THE LEAD TETRAACETATE-LITHIUM CHLORIDE SYSTEM IN THE PRESENCE OF PERFLUORINATED CARBOXYLIC ACIDS
-
The oxidation of benzene and substituted benzenes PhX with electron-donating (X = CH3, OCH3) and electron-withdrawing (X = Hlg, CF3, NO2) substituents in the Pb(OAc)4-LiCl system was investigated in the presence of perfluorinated carboxylic acids RfCOOH (Rf = CF3, C6F13).The reaction leads to the plumbation, chlorination, and acyloxylation products.It was shown that the reactions take place through the formation of aryl derivatives of lead(IV) with the participation of mixed-ligand complexes of lead.The products from the plumbation of toluene (in C6F13COOH in the absence of lithium chloride) and benzotrifluoro were isolated.In trifluoroacetic acid these intermediates undergo intramolecular redox decomposition with ligand transfer.The halogenobenzenes and benzotrifluoride are oxidized selectively in the CF3COOH-Pb(IV)-LiCl system, giving the corresponding aryl chlorides with yields close to quantitative (80-90percent).
- Serguchev, Yu. A.,Davydova, V. G.,Makhon'kov, D. I.,Beletskaya, I. P.
-
p. 1006 - 1011
(2007/10/02)
-
- A Simple and General Route to Aryl Iodides from Arenes
-
Mercury(II) oxide-tetrafluoroboric acid reacts with arenes under mild or very mild conditions to afford, after treatment with iodine in a 'one-stage' reaction, the corresponding aryl iodide.The orientation is that expected based on general aromatic substitution theory and hence the meta-iodinated derivatives of deactivated arenes are accessible.
- Barluenga, Jose,Campos, Pedro J.,Gonzalez, Jose M.,Asensio, Gregorio
-
p. 2623 - 2624
(2007/10/02)
-
- Oxidative Displacement of Halogen from Alkyl Halides by Phenyliodine(III) Dicarboxylates
-
The reaction of alkyl iodides with aryliodine(III) dicarboxylates affords as the main product the ester derived through substitution of iodine by an acyloxy group; in some cases α-iodoalkyl esters are also formed along with other minor products.Certain reactive bromides and chlorides react along similar lines.The mechanism of these reactions is briefly discussed.
- Gallos, John,Varvoglis, Anastasios
-
p. 1999 - 2002
(2007/10/02)
-
- AROMATIC IODINATION WITH ALUMINUM AND COPPER (II) CHLORIDES AND IODINE
-
Aryl iodides have been synthesized by a simple reaction of aromatic compounds with iodine and an equimolecular mixture of aluminum and copper(II) chlorides.The reaction is widely capable of application, especially to liquid aromatic substrates, with fair to excellent yields.
- Sugita, Toshio,Idei, Mitsushige,Ishibashi, Yoshiyuki,Takegami, Yoshinobu
-
p. 1481 - 1484
(2007/10/02)
-
- Nucleophilic Displacement in Polyhalogenoaromatic Compounds. Part 11. Kinetics of Protiodeiodination of Iodoarenes in Dimethyl Sulphoxide-Methanol
-
The rates of methoxide-ion induced protiodeiodination of a number of polychloroiodobenzenes and their derivatives have been measured in dimethyl sulphoxide-methanol (9:1 v/v; 323.2 K).The true reagent under these conditions appears to be the dimethyl sulphoxide anion, and the rates of reaction in some cases appear to approach that expected of a diffusion controlled process.This corresponds to a major decrease in the efficacy of further activating substituents in the aromatic system, altough deactivating groups such as p-OMe still show large effects.Chlorine promotes protiodeiodination in the order of efficiency o-Cl > m-Cl > p-Cl; the trifluoromethyl group activates displacement in the order o-CF3 > p-CF3 > m-CF3, although with much less difference between isomeric sites. o-Nitro-groups promote protiodeiodination whereas the p-nitro-group encourages methoxydeiodination.No evidence of methoxydeiodination was found in attack of the polychloroiodobenzenes, although the rates of methoxydechlorination of the corresponding polychlorobenzenes suggest that in some cases this might occur.Evidence rejecting the possible SRN1 mechanism and supporting nucleophilic attack by a carbanionic species upon iodine is presented.
- Bolton, Roger,Moore, Clive,Sandall, John P.B.
-
p. 1593 - 1598
(2007/10/02)
-
- The synthesis of [3H] and [14C]o- chlorobenzylidenemalononitrile (CS)
-
Using similar procedures, the syntheses of [2-14C]-malononitrile and malono [14C]nitrile are described. Condensation with o-chlorobenzaldehyde affords [2-14C]-o-chlorobenzylidenemalononitrile and o-chlorobenzylidenemalono [14C]nitrile respectively. The syntheses of [3H]o-chlorobenzaldehyde and o-chlorobenz[ 14C]aldehyde, again by a common sequence of reactions, is described and with malononitrile gives [3H]-o-chlorobenzylidenemalononitrile and [1-14C]-o-chlorobenzylidenemalononitrile.
- Harrison,Inch,Lawston,Ley,Sainsbury
-
p. 141 - 148
(2014/02/14)
-