- PERFLUOROPOLYMER-SUPPORTED FITS REAGENTS
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Perfluoropolymer-supported FITS reagents (FITS-Nafion) were synthesized by treatment of bis(trifluoroacetoxy)iodoperfluoroalkenes with perfluorosulfonic acid resin (Nafion-H) and benzene or fluorobenzene.
- Umemoto, Teruo
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Read Online
- Oxidative Addition, Transmetalation, and Reductive Elimination at a 2,2′-Bipyridyl-Ligated Gold Center
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Three-coordinate bipyridyl complexes of gold, [(κ2-bipy)Au(η2-C2H4)][NTf2], are readily accessed by direct reaction of 2,2′-bipyridine (bipy), or its derivatives, with the homoleptic gold ethylene complex [Au(C2H4)3][NTf2]. The cheap and readily available bipyridyl ligands facilitate oxidative addition of aryl iodides to the Au(I) center to give [(κ2-bipy)Au(Ar)I][NTf2], which undergo first aryl-zinc transmetalation and second C-C reductive elimination to produce biaryl products. The products of each distinct step have been characterized. Computational techniques are used to probe the mechanism of the oxidative addition step, offering insight into both the origin of the reversibility of this process and the observation that electron-rich aryl iodides add faster than electron-poor substrates. Thus, for the first time, all steps that are characteristic of a conventional intermolecular Pd(0)-catalyzed biaryl synthesis are demonstrated from a common monometallic Au complex and in the absence of directing groups.
- Harper, Matthew J.,Arthur, Christopher J.,Crosby, John,Emmett, Edward J.,Falconer, Rosalyn L.,Fensham-Smith, Andrew J.,Gates, Paul J.,Leman, Thomas,McGrady, John E.,Bower, John F.,Russell, Christopher A.
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Read Online
- Selective C-H Iodination of (Hetero)arenes
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Iodoarenes are versatile intermediates and common synthetic targets in organic synthesis. Here, we present a strategy for selective C-H iodination of (hetero)arenes with a broad functional group tolerance. We demonstrate the utility and differentiation to other iodination methods of supposed sulfonyl hypoiodites for a set of carboarenes and heteroarenes.
- Tanwar, Lalita,B?rgel, Jonas,Lehmann, Johannes,Ritter, Tobias
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supporting information
p. 5024 - 5027
(2021/06/30)
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- Palladium-Catalyzed Decarbonylative Iodination of Aryl Carboxylic Acids Enabled by Ligand-Assisted Halide Exchange
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We report an efficient and broadly applicable palladium-catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt. The use of 1-iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis, including complex drug-like scaffolds. Stoichiometric experiments and kinetic analysis suggest a unique mechanism involving C?P reductive elimination to form the Xantphos phosphonium chloride, which subsequently initiates an unusual halogen exchange by outer sphere nucleophilic substitution.
- Boehm, Philip,Cacherat, Bastien,Lee, Yong Ho,Martini, Tristano,Morandi, Bill
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supporting information
p. 17211 - 17217
(2021/07/02)
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- A convenient synthetic approach to a novel class of aryldifluoromethyl pyrimidine derivatives containing strobilurin motif as insecticidal agents
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A series of aryldifluoromethyl pyrimidine compounds containing strobilurin were synthesized through bioelectronic isometric design with azoxystrobin as the lead compound and a convenient approach to aryldifluoromethylpyrimidine intermediates was developed, which features mild reaction conditions and simple operation. The title compounds and aryldifluoromethylpyrimidine intermediates were characterized by NMR and HRMS. Both 7c and 7l of the preliminary screening tests showed 100% inhibition against Mythimna separata at 100 mg/L. At 20 mg/L, the lethal rate of 7l against Mythimna separata can be up to 80%.
- Cai, Zengfei,Cao, Yangyang,Du, Xiaohua,Hao, Shulin,Zhang, Wenliang
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supporting information
(2021/10/07)
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- Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions
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A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.
- Yang, Yu-Ming,Yan, Wei,Hu, Han-Wei,Luo, Yimin,Tang, Zhen-Yu,Luo, Zhuangzhu
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p. 12344 - 12353
(2021/09/02)
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- Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
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Heterogeneous homocoupling reactions of phenylboronic acids were greatly accelerated via Suzuki homocoupling reactions. In this work, a tandem route was designed which firstly one part of phenylboronic acids reacted with iodine to form iodobenzenes, then another part of phenylboronic acids coupled with iodobenzenes to produce biaryl compounds. The tandem reaction were catalyzed by a bifunctional heterogeneous catalyst of metal organic frameworks encapsulated with palladium nanoparticles (Pd?MOFs). This strategy for forming symmetric C-C bond between benzene rings has obvious advantages such as high efficiency, easy separation, good recyclability and no addition of toxic halogenated benzene.
- Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
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- Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
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While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism.
- Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
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supporting information
p. 18717 - 18722
(2020/08/25)
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- Photoredox catalysis with aryl sulfonium salts enables site-selective late-stage fluorination
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Photoredox catalysis, especially in combination with transition metal catalysis, can produce redox states of transition metal catalysts to facilitate challenging bond formations that are not readily accessible in conventional redox catalysis. For arene functionalization, metallophotoredox catalysis has successfully made use of the same leaving groups as those valuable in conventional cross-coupling catalysis, such as bromide. Yet the redox potentials of common photoredox catalysts are not sufficient to reduce most aryl bromides, so synthetically useful aryl radicals are often not directly available. Therefore, the development of a distinct leaving group more appropriately matched in redox potential could enable new reactivity manifolds for metallophotoredox catalysis, especially if arylcopper(iii) complexes are accessible, from which the most challenging bond-forming reactions can occur. Here we show the conceptual advantages of aryl thianthrenium salts for metallophotoredox catalysis, and their utility in site-selective late-stage aromatic fluorination.
- Li, Jiakun,Chen, Junting,Sang, Ruocheng,Ham, Won-Seok,Plutschack, Matthew B.,Berger, Florian,Chabbra, Sonia,Schnegg, Alexander,Genicot, Christophe,Ritter, Tobias
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- Facile Access to Diverse Libraries of Internal Alkynes via Sequential Iododediazoniation/Decarboxylative Sonogashira Reaction in Imidazolium ILs without Ligand or Additive
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Convenient access to diverse libraries of internal alkynes via decarboxylative Sonogashira reaction of alkynyl-carboxylic acids with iodoarenes, employing imidazolium-ILs as solvent, along with piperidine-appended imidazolium [PAIM][NTf2] as task-specific basic IL is demonstrated, without the need for any ligand or additive. The feasibility to perform these reactions by sequential one-pot iododediazoniation/decarboxylative Sonogashira reaction is also shown, and the scope of the methods is underscored by providing 29 examples. The potential for recycling and reuse of the IL solvent is also examined.
- Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
p. 2061 - 2064
(2019/03/07)
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- Method for catalyzing deaminized boric acid esterification or halogenation of arylamine
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The invention belongs to the technical field of organic synthesis and in particular discloses a method for catalyzing deaminized boric acid esterification or halogenation of arylamine. The method comprises the following steps: putting arylamine and a nitroso type compound into a mixed solvent, and performing a reaction at 0-5 DEG; and further adding a raw material capable of providing a functionalization group A and a catalysis amount of a reaction accelerator, and performing deamination functionalization reaction under light radiation at 10-50 DEG C, so as to obtain a product that an amino site of the arylamine is modified by the functionalization group A. Due to synergetic control on substrates, reaction solvents, material mixing modes, temperatures, reaction accelerators and addition amounts, boric acid esterification or halogenation of arylamine, particularly electron donating substituted arylamine which is hard to treat effectively in technical schemes of the industry, can be achieved.
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Paragraph 0063; 0082-0084
(2020/01/12)
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- Mechanism of Cu-catalyzed aryl boronic acid halodeboronation using electrophilic halogen: Development of a base-catalyzed iododeboronation for radiolabeling applications
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An investigation into the mechanism of Cu-catalyzed aryl boronic acid halodeboronation using electrophilic halogen reagents is reported. Evidence is provided to show that this takes place via a boronate-driven ipso-substitution pathway and that Cu is not required for these processes to operate: General Lewis base catalysis is operational. This in turn allows the rational development of a general, simple, and effective base-catalyzed halodeboronation that is amenable to the preparation of 125I-labeled products for SPECT applications.
- Molloy, John J.,O'rourke, Kerry M.,Frias, Carolina P.,Sloan, Nikki L.,West, Matthew J.,Pimlott, Sally L.,Sutherland, Andrew,Watson, Allan J. B.
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supporting information
p. 2488 - 2492
(2019/04/10)
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- A general electrochemical strategy for the Sandmeyer reaction
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Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
- Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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p. 8731 - 8737
(2018/12/10)
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- Electrochemical Synthesis of Aryl Iodides by Anodic Iododesilylation
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An electrochemical access to iodinated aromatic compounds starting from trimethylsilyl-substituted arenes is presented. By design of experiments, highly efficient and mild conditions were identified for a wide range of substrates. A functional group stability test and the synthesis of an important 3-iodobenzylguanidine radiotracer illustrate the scope of this process.
- M?ckel, Robert,Hille, Jessica,Winterling, Erik,Weidemüller, Stephan,Faber, Tabea Melanie,Hilt, Gerhard
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supporting information
p. 442 - 445
(2018/02/21)
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- Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
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A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
- Maity, Saurabh,Das, Debapratim,Sarkar, Souradip,Samanta, Rajarshi
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supporting information
p. 5167 - 5171
(2018/09/13)
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- Easy Access to Difluoromethylene-Containing Arene Analogues through Palladium-Catalysed C–H Olefination
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An efficient palladium-catalysed ortho-C–H olefination of α,α-difluorophenylacetic acid derivatives using 8-aminoquinoline as a bidentate directing group has been developed. A range of olefinated arenes can thus be synthesized in a concise way. This reaction provides an easy and straightforward route to a panel of difluoromethylated arene analogues in moderate to good yields, with a satisfactory tolerance of common functional groups. Transformation of the products into a variety of other difluoromethylene-containing compounds demonstrates the utility of this method.
- Shao, Changdong,Shi, Guangfa,Zhang, Yanghui
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supporting information
p. 5529 - 5538
(2016/11/25)
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- Copper-mediated aerobic iodination and perfluoroalkylation of boronic acids with (CF3)2CFI at room temperature
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The copper-mediated aerobic reactions between the branched (CF3)2CFI and boronic acids (R-B(OH)2) are described. Different from the linear perfluoroalkyl analogs CF3(CF2)nI (n?=?2, 3, 5, 7), (CF3)2CFI reacting with R-B(OH)2at room temperature under air in the presence of catalytic Cu powder provided exclusively the corresponding iodides (R-I), while the aerobic reactions of arylboronic acids with (CF3)2CFI at room temperature in the presence of Cu(OAc)2gave the perfluoroalkylation products (R-CF(CF3)2) in acceptable to moderate yields. The iodination reaction could be further promoted by hydroquinone, the addition of which improved the oxidation ability of (CF3)2CFI and provided the ipso-iodination products in high yields. The perfluoroalkylation was facilitated by the copper carboxylates since the addition of these salts into the reaction mixtures could successfully give rise to Ar-CF(CF3)2.
- Liu, Xi-Hai,Leng, Jing,Jia, Su-Jiao,Hao, Jian-Hong,Zhang, Fanglin,Qin, Hua-Li,Zhang, Cheng-Pan
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- Photoinitiated oxidative addition of CF3I to gold(I) and facile aryl-CF3 reductive elimination
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Herein we report the mechanism of oxidative addition of CF3I to Au(I), and remarkably fast Caryl-CF3 bond reductive elimination from Au(III) cations. CF3I undergoes a fast, formal oxidative addition to R3PAuR' (R = Cy, R' = 3,5-F2-C 6H4, 4-F-C6H4, C6H 5, 4-Me-C6H4, 4-MeO-C6H4, Me; R = Ph, R' = 4-F-C6H4, 4-Me-C6H 4). When R' = aryl, complexes of the type R3PAu(aryl) (CF3)I can be isolated and characterized. Mechanistic studies suggest that near-ultraviolet light (λmax = 313 nm) photoinitiates a radical chain reaction by exciting CF3I. Complexes supported by PPh3 undergo reversible phosphine dissociation at 110 °C to generate a three-coordinate intermediate that undergoes slow reductive elimination. These processes are quantitative and heavily favor C aryl-I reductive elimination over Caryl-CF3 reductive elimination. Silver-mediated halide abstraction from all complexes of the type R3PAu(aryl)(CF3)I results in quantitative formation of Ar-CF3 in less than 1 min at temperatures as low as -10 °C.
- Winston, Matthew S.,Wolf, William J.,Toste, F. Dean
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p. 7777 - 7782
(2014/06/10)
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- FLUORINATION OF ARYL COMPOUNDS
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The invention provides compositions and methods of using the compositions in fluorinating aryl precursors containing a leaving group replaceable by a fluorine atom. The compositions include a metal ion source, a electrophilic fluorine source, a base, and a compound, which is an aryl precursor of the aryl fluoride, and which has a leaving group replaceable by the fluorine atom. Exemplary methods of the invention make use of such compositions and methods to prepare an aryl fluoride compound. In an exemplary embodiment, the electrophilic fluorine source is a source of 18F.
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Paragraph 00117; 00118-00121
(2014/07/22)
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- Aromatic fluoro-de-triazenation with boron trifluoride diethyl etherate under non-protic acid conditions
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Fluoro-de-triazenation of 3,3-diethyl-1-aryltriazenes can be achieved by conventional or under microwave heating in carbon tetrachloride, in the presence of boron trifluoride diethyl etherate without any protic acid to avoid corresponding unwanted byproduct formation.
- Kovac, Mitja,Anderluh, Marko,Vercouillie, Johnny,Guilloteau, Denis,Emond, Patrick,Mavel, Sylvie
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- Copper-mediated fluorination of arylboronate esters. Identification of a Copper(III) fluoride complex
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A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through arylboronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III), followed by rate-limiting transmetalation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS.
- Fier, Patrick S.,Luo, Jingwei,Hartwig, John F.
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supporting information
p. 2552 - 2559
(2013/03/29)
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- A simple and effective copper catalyst for the conversion of arylboronic acids to aryl iodides at room temperature
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Simple Cu(NO3)2·3H2O was demonstrated to be of ability to catalyze the conversion of arylboronic acids to aryl iodides at room temperature. Compared with the previous copper-catalyzed method, the present procedure avoids the use of the ligand, the oxidant as well as the heating condition.
- Ren, Yun-Lai,Tian, Xin-Zhe,Dong, Chuanhua,Zhao, Shuang,Wang, Jianji,Yan, Mengjie,Qi, Xiaoguang,Liu, Guihua
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- Electrophilic fluorination of organoplatinum(II) iodides: Iodine and platinum atoms as competing fluorination sites
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A series of diphosphine Pt(II) aryl iodo complexes were reacted with XeF2 to cleanly produce the corresponding Pt(II) difluoro complexes and free iodoarenes. However, when aryl ligands bearing fluoro substituents in the ortho positions were used, the formation of the corresponding Pt(II) aryl fluoro complexes was observed in the reaction with XeF2. In the case of the Pt-C6F5 complex, the products of the fluoride-for-iodide exchange were the only products observed by means of 31P and 19F NMR spectroscopy. The experimental and theoretical studies suggest that the formation of iodine-fluorine bond may accompany this transformation. The plausible I-F species could be trapped by electron-richer organoplatinum complexes to give a Pt(IV) transient which subsequently eliminates the corresponding aryl iodide. Hence, in some cases a pathway involving an attack of XeF2 at the iodo ligand of Pt(II) aryl iodo complexes to generate I-F species can be operative in addition to or instead of the XeF2 attack at the metal center. Our DFT studies demonstrate that the electrophilic attacks of XeF2 at both sites, platinum and iodide, can be competitive.
- Dubinsky-Davidchik, Ina S.,Potash, Shay,Goldberg, Israel,Vigalok, Arkadi,Vedernikov, Andrei N.
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supporting information
p. 14027 - 14032
(2012/10/29)
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- Tetraflic acid (1,1,2,2-Tetrafluoroethanesulfonic acid, HC 2F4SO3H) and gallium tetraflate as effective catalysts in organic synthesis
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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.
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p. 2163 - 2171
(2012/11/07)
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- Cobalt-catalyzed preparation of arylindium reagents from aryl and heteroaryl bromides
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A cobalt-bathophenanthroline catalyst has been developed for the direct preparation of a variety of arylindium reagents from the corresponding aryl and heteroaryl bromides in the presence of indium metal and lithium chloride. The thus-formed arylindium reagents undergo efficient palladium-catalyzed cross-coupling reactions with aryl iodides, tolerating various functional groups including hydroxy and free amino groups.
- Adak, Laksmikanta,Yoshikai, Naohiko
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experimental part
p. 7563 - 7568
(2011/11/12)
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- General copper-catalyzed transformations of functional groups from arylboronic acids in water
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A simple and general copper-catalyzed method has been developed for transformations of various functional groups (i I, i N3, i SO2R, i OH, i NH2, and i NO 2) on aromatic rings from arylboronic acids in water under air. The protocol uses cheap and readily available inorganic salts (KI, NaN3, NaSO2R, NaOH, NaNO2) and aqueous ammonia as the functional-group sources, simple Cu2O/NH3 as the catalyst system, environmentally friendly water as the solvent, and oxygen in air as the oxidant. Importantly, the copper catalyst system in water was recyclable. This study should provide a useful strategy for interconversions of the functional groups on aromatic rings.
- Yang, Haijun,Li, Yong,Jiang, Min,Wang, Junmei,Fu, Hua
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experimental part
p. 5652 - 5660
(2011/06/23)
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- Superelectrophilic iodination of deactivated arenes with triiodoisocyanuric acid
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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.
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experimental part
p. 739 - 744
(2011/04/24)
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- Synthesis of aryl fluorides on a solid support and in solution by utilizing a fluorinated solvent
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(Figure Presented) F for fast: The perfluorinated solvent C 6F14 is the key to a new variant of the BalzSchiemann reaction for the synthesis of fluorinated arenes. Triazenes are converted into fluoroarenes under mild con-ditions on a support and in solution (see scheme). The method is straightforward and inexpensive, and yields previously difficult-to-prepare fluoroarenes in high purity.
- Doebele, Marion,Vanderheiden, Sylvia,Jung, Nicole,Braese, Stefan
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supporting information; experimental part
p. 5986 - 5988
(2010/10/01)
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- Direct synthesis of iodoarenes from aromatic substrates using molecular iodine
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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
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p. 690 - 692
(2008/09/21)
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- Synthesis of arylcalcium halides - General procedure, scope and limitations
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A general procedure for the synthesis of a wide variety of arylcalcium halides by activation of the alkaline earth metal as well as bromo- or iodoarenes is reported. Chloro- and fluoroarenes are not suitable substrates for an insertion of calcium into the carbon-halogen bond. Furthermore, ortho-fluoro substitution prevents the formation of the corresponding heavy calcium organometallics. The ipso-carbon atoms show a strong low-field shift in the 13C NMR spectra. The arylcalcium iodides crystallize monomeric as tetrakis(THF) complexes. Naphthylcalcium iodide shows a Ca-C bond length of 255.2(6) pm which lies in the characteristic region. Georg Thieme Verlag Stuttgart.
- Gaertner, Martin,Goerls, Helmar,Westerhausen, Matthias
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p. 725 - 730
(2008/01/01)
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- Ambient-temperature molten salts and process for producing the same
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Ambient-temperature molten salts of formula (I): wherein Y+ is a cation selected from the group consisting of an ammonium ion, a sulfonium ion, a pyridinium ion, a(n) (iso)thiazolium ion, and a(n) (iso)oxazolium ion that may be optionally substituted with C1-10 alkyl and/or C1-10 alkyl having ether linkage, provided that the above cation has at least one substituent of —CH2Rf1 or —OCH2Rf1 (wherein Rf1 is C1-10 perfluoroalkyl); Rf2 and Rf3 are independently C1-10 perfluoroalkyl or may together form C1-4 perfluoroalkylene; and X is —SO2- or —CO—.
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Page/Page column 10; 11
(2008/06/13)
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- 2-Methoxy-4-nitrobenzenediazonium salt as a practical diazonium-transfer agent for primary arylamines via tautomerism of 1,3-diaryltriazenes: Deaminative iodination and arylation of arylamines without direct diazotization
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1,3-Diaryltriazenes, prepared from a 2-methoxy-4-nitrobenzenediazonium salt and primary arylamines, exist as "azo-transfer" tautomers in which the 2-methoxy-4-nitrophenyl group is present on the saturated nitrogen atom and forms a hydrogen bond between the 2-methoxy group and the N-H moiety. The synthetic utility of the diazonium salt as a practical diazonium-transfer agent for primary arylamines via tautomerism of the 1,3-diaryltriazenes has been demonstrated by the deaminative iodination and arylation of the arylamines without direct diazotization. The starting 2-methoxy-4-nitrophenylamine can be easily recovered after the reactions.
- Saeki, Tomoyuki,Son, Eun-Cheol,Tamao, Kohei
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p. 1654 - 1658
(2007/10/03)
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- PROCESS FOR PRODUCTION OF IODINE COMPOUNDS AND PROCESS FOR PRODUCTION OF HIGH-PURITY 5-IODO-2-METHYLBENZOIC ACID
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Provided is a production method for an iodine compound in which iodine is reacted with a substrate in the presence of a porous material having a pore diameter of 500 nm or less or in the presence of the above porous material and an oxidizing agent and a production process for high purity 5-iodo-2-methylbenzoic acid comprising an iodination reaction step carried out by the above-mentioned, a crystal precipitation and separation step in which a product is precipitated by adding water or cooling and then separated and a purification step in which crystal separated is recrystallized using an organic solvent. According to the production method for an iodine compound described above, iodine can be introduced into various substrates at a high selectivity. Since expensive metals and specific reagents do not have to be used, it can readily be carried out in an industrially scale, and the product having a high purity can be obtained. Further, the process comprising the iodination reaction, separation and purification steps described above makes it possible to readily obtain at a high yield, 5-iodo-2-methylbenzoic acid having a high purity which is useful in uses for functional chemical products such as medicines. The process of the present invention comprising iodination reaction, separation and purification steps is characterized by that it is simple in terms of a procedure and that the purification load is smaller, and it is very advantageous in industrially carrying out.
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Page/Page column 9
(2008/06/13)
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- N-halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
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N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. Because BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H0 ≈ 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF3-H2O has been developed. DFT calculations at the B3LYP/6-311++G**//B3LYP/6-31G* level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X+ from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X+ which would readily react with the aromatic substrates. Structural aspects of the BF 3-H2O complex have also been investigated.
- Prakash, G. K. Surya,Mathew, Thomas,Hoole, Dushyanthi,Esteves, Pierre M.,Wang, Qi,Rasul, Golam,Olah, George A.
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p. 15770 - 15776
(2007/10/03)
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- Chemical Manganese Dioxide (CMD): Its application to the oxidative iodination of benzene, halobenzenes and some deactivated arenes
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After comparing our previous and newer results for numerous oxidative aromatic iodination experiments using various brands (of active MnO2 as the oxidants, we recommend the use of a Chemical Manganese Dioxide (Aldrich CMD; 90+% (MnO2) as the oxidant of choice, since it is satisfactorily pure and chemically active, and is notably less costly than other options.
- Lulinski, Piotr,Krassowska-Swiebocka, Barbara,Skulski, Lech
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p. 595 - 601
(2007/10/03)
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- Method for producing tetrakis ( fluoroaryl) borate-magnesium compound
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Fluoroaryl magnesium halide is reacted with a boron compound so that a molar ratio of the fluoroaryl magnesium halide to the boron compound is not less than 3.0 and not more than 3.7, so as to produce a tetrakis (fluoroaryl) borate·magnesium compound. With this method, there occurs no hydrogen fluoride which corrodes a producing apparatus and requires troublesome waste water treatment.
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- Iodination of both deactivated and activated arenes with sodium periodate or sodium iodate as the oxidants
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Five easy, relatively inexpensive, and environmentally-safe aromatic oxidative iodination procedures are presented; three of them are particularly suitable for deactivated arenes. Nine deactivated arenes, four halobenzenes, benzene, toluene, and N,N-dimethylaniline were reacted upon with the following anhydrous systems: diiodine/NaIO4 or (in four cases) NaIO3/acetic anhydride/glacial acetic acid, acidified with varying amounts of concd (98%) sulfuric acid; the following workups are explained. The aromatic oxidative iodination reactions proceeded mostly at room temperature and within 1-8 h to give fifteen mono- and two diiodinated purified products (sometimes obtained in 2-3 different ways) in 51-95% yields.
- Lulinski, Piotr,Skulski, Lech
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p. 951 - 956
(2007/10/03)
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- The reactivity of organothallium compounds. Kinetics and mechanism of iodination of diarylthallium salts by molecular iodine in dioxane
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The kinetics and mechanism of the reactions of diarylthallium trifluoroacetates with molecular iodine in dioxane solutions have been studied. The reaction has the overall second order with the first order with respect to each reagent. The effect of substi
- Gun'kin,Butin
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p. 448 - 452
(2007/10/03)
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- Oxidative iodination of arenes with manganese(IV) oxide or potassium permanganate as the oxidants
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Novel and easy laboratory methods (novel Procedures 1-4) are presented for the oxidative mono- and diiodination of both activated and deactivated arenes, which gave the pure iodinated products in 62-89% yields. The reactions were carried out in the anhydrous, strongly acidic system, I2/activated MnO2/AcOH/Ac2O/concd H2SO4, firstly at r.t. for 2 h, then at 45-55 °C for 2-9 h. The resulting mixtures were poured into excess aq Na2SO3 solution buffered with (NH4)2CO3 to neutralize H2SO4. The following workups are given. Similarly, on carrying out the iodination reactions (at 35 °C, for one hour) in the anhydrous, strongly acidic system, I2/KMnO4/AcOH/Ac2O/concd H2SO4, it was possible to mono- or diiodinate several deactivated arenes in 73-87% yields (improved Procedures 5 and 6).
- Lulinski, Piotr,Skulski, Lech
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p. 115 - 120
(2007/10/03)
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- The direct iodination of arenes with chromium(VI) oxide as the oxidant
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An easy and cheap laboratory method is presented for the direct mono- and diiodination of a number of activated and deactivated arenes. The main iodination reactions occurred at the temperatures not exceeding 65°C for 0.5-12 h in the anhydrous, strongly acidic liquid system, I2/AcOH/Ac2O/H2SO4, in the presence of prior dissolved CrO3 used as the oxidant. The yields of the pure iodinated products varied from 31% (for 3,5- diiodobenzoic acid) up to 90% (for 4-iodoanisole). So far, benzonitrile and some oxidizable aromatics, e.g. naphthalene, fluorene, xanthene, and thiophene, have been found to be unsuitable for the effective iodination. Nevertheless, this novel, simple method of direct iodination is worthy to be extended to other appropriate aromatics.
- Lulinski, Piotr,Skulski, Lech
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p. 1665 - 1669
(2007/10/03)
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- A Novel Aromatic Iodination Method Using F2
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A new method for direct aromatic iodination with IF, made in situ from the corresponding elements, is described.Depending on the reaction time and temperature, mono- or polyiodination can be achieved.Even deactivated aromatic rings can be directly iodinated without the presence of any Friedel-Crafts catalyst.Sensitive groups such as aromatic aldehydes are not affected by the reagent.
- Rozen, Shlomo,Zamir, Dov
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p. 3552 - 3555
(2007/10/02)
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- Lower Nitrogen Oxide Species as Catalysts in a Convenient Procedure for the Iodination of Aromatic Compounds
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A simple method for the iodination of aromatic compounds, using I- as the iodine source and the O2 and catalytic amounts of NO+BF4- as the oxidant, is presented.The reactions are performed at 25 deg C in CF3COOH/CH2Cl2 or CF3COOH/CH3COOH mixtures and compounds with as different reactivities as the halobenzenes and 1-methoxynaphthalene can be iodinated in very good yields.A set of relative rates, isotope effects, and isomer distributions in accordance with the electrophilic action of an "I+" species are presented.The formation of "I+" is discussed in terms of possible outer-sphere and inner-sphere electron-transfer steps.Aromatic bromination and to a lesser extent chlorination can be performed by using similar methods.
- Radner, Finn
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p. 3548 - 3553
(2007/10/02)
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- STOICHIOMETRIC AND CATALYTIC OXIDATIVE IODINATION OF AROMATIC COMPOUNDS IN THE PRESENCE OF NITROGEN-CONTAINING OXIDIZING AGENTS IN AQUEOUS TRIFLUOROACETIC ACID
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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.
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p. 2029 - 2035
(2007/10/02)
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- Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K
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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
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p. 1167 - 1174
(2007/10/02)
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- Dediazoniation of Arenediazonium Ions. 24. Dual and Triple Substituen Parameter Evaluation of Competitive Heterolytic and Homolytic Dediazoniations of Diazonium Ions Complexed with 18-Crown-6 Ether
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The dediazoniation of eight para-substituted benzenediazonium ions in 1,2-dichloroethane is a heterolytic reaction.The corresponding 18-crown-6 ether complexes of these diazonium ions, however, react also homolytically.The rate constants for heterolytic dediazoniation of the free diazonium ions (k1), the rate constants for competitive heterolytic and homolytic dediazoniation of the crown ether complexed diazonium ions (k3 and k4, respectively), and the equilibrium constants for formation of the diazonium ion-crown ether complexes (K) were correlated with dual substituent parameter (DSP) treatments.A comparison has been made with the following substituent constants: Taft's original DSP substituent constants, Taft's triple substituent parameter constants (TSP) based on gas-phase reactions (1987), Charton's modified DSP constants, and the original (1968) and revised (1983) constants proposed by Swain.The reaction constants with the best (smallest) standard deviations and confidence limits and the highest regression coefficients are obtained with the substituent constants of Taft (both the original and the new gas-phase constants) and those of Charton.The heterolytic dediazoniation is characterized by clearly opposing signs of the field and resonance reaction constants ( and ), in contrast to the homolytic dediazoniations.The DSP treatments currently available do not provide meaningful results with homolytic dediazoniation.
- Nakazumi, Hiroyuki,Kitao, Teijiro,Zollinger, Heinrich
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p. 2825 - 2830
(2007/10/02)
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- ELECTROCATALYSE PAR DES COMPLEXES DU NICKEL DE LA SYNTHESE D'IODURES AROMATIQUES OU VINYLIQUES A PARTIR DE DERIVES BROMES CORRESPONDANTS
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In the solvent N-methyl-2-pyrrolidone the electrochemical reduction of nickel bromide in the presence of potassium iodide, leads to Ni(O) species which are very efficient in the catalytic halogen exchange.Conversion of non-activated aromatic bromides into the corresponding iodides is achieved in good yields, specially when anisole is added to the medium.
- Meyer, Gilbert,Rollin, Yolande,Perichon, Jacques
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p. 3497 - 3500
(2007/10/02)
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- 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
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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.
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p. 1003 - 1006
(2007/10/02)
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