- The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
-
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
- Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
-
supporting information
p. 5680 - 5686
(2021/08/16)
-
- Preparation method of m-nitrobenzotrifluoride
-
The invention relates to a preparation method of m-nitrobenzotrifluoride. The method includes carrying out nitration reaction on trifluorotoluene, concentrated sulfuric acid and nitric acid in an organic solvent; specifically, stirring trifluorotoluene, an organic solvent and concentrated sulfuric acid under the condition that the temperature is controlled to be 30-40 DEG C, adding fuming nitric acid is dropwise, performing a heat preservation reaction for 6-10 h; after the reaction is completed, standing and performing liquid separation, adjusting the pH of an organic phase to be alkaline with an alkaline aqueous solution, performing desolvation on the organic phase, and finally performing reduced pressure distillation to obtain m-nitrotrifluorotoluene. According to the invention, dichloroethane, carbon tetrachloride and other chlorinated non-polar solvents are used as reaction solvents for nitration reaction, so violent heat release in the nitration reaction process is reduced, the reaction conditions are mild, and the safety is improved; meanwhile, the dosage of acid and the dosage of post-treatment alkali are greatly reduced, and three wastes are reduced, so that the post-treatment is simple, the product is easy to separate, the operation is simple and convenient, side reactions are few, the yield is high, the product purity is high and the process pollution is small.
- -
-
Paragraph 0038-0045; 0049-0051
(2020/08/22)
-
- o-aminotrifluorotoluene synthesis method
-
The invention discloses an o-aminotrifluorotoluene synthesis method, wherein trifluorotoluene is used as a raw material, and a target compound is obtained through two-step reaction of nitration and reduction. Compared with the method in the prior art, the method of the invention has the following characteristics that trifluorotoluene is used as the raw material, so that the source is wide, and thepreparation is convenient; the nitration reaction is carried out at a normal pressure and a low temperature, so that the corrosion of the material to the pipeline and the equipment is small, and thenitration reaction is safe and reliable to the environment and operators; and the cheap nickel catalyst is used for replacing the common noble metal catalysts such as palladium, platinum and the like,so that the production cost is reduced, the methanol as the solvent is convenient to recover and can be recycled, and the emission of organic matters in the production process is reduced.
- -
-
Paragraph 0005; 0013; 0016; 0019
(2020/01/25)
-
- NITRATION
-
The present invention relates to a process for preparing a nitrated compound, comprising the step of reacting a compound (A) comprising at least one substituted or unsubstituted aromatic or heteroaromatic ring, wherein said heteroaromatic ring comprises at least one heteroatom selected from the group consisting of oxygen, sulfur, phosphor, selenium and nitrogen, with a compound of formula (I) wherein Y is selected from the group consisting of hydrogen and nitro.
- -
-
Page/Page column 36; 37; 47; 66-67; 38; 49-50; 42; 65-66
(2020/05/28)
-
- Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent
-
The trifluoromethylation of iodoarenes was accomplished by use of a 2-trifluoromethylbenzimidazoline derivative as the trifluoromethylating reagent and a catalytic amount of Cu(I) in the presence of 2,2'-bipyridyl as the ligand. Through a mechanistic study, we found that the oxidative addition of the iodoarene to the Cu(I)–CF3 species is the rate-determining step.
- Akiyama, Takahiko,Ishikawa, Taisuke,Kamiyama, Nanami,Uchikura, Tatsuhiro
-
supporting information
p. 2442 - 2447
(2020/11/07)
-
- Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides
-
A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also successfully carried out with this metal-free catalytic system in good to excellent yields.
- Gupta, Sampa,Ansari, Alisha,Sashidhara, Koneni V.
-
supporting information
(2019/09/07)
-
- Ligand-free trifluoromethylation of iodoarenes by use of 2-Aryl-2-trifluoromethylbenzimidazoline as new trifluoromethylating reagent
-
N-Methyl 2-aryl-2-trifluoromethylbenzimidazolines were synthesized and utilized in the trifluoromethylation reaction of iodoarenes in the presence of copper(I) salt and base. Iodoarenes bearing electron-donating and electron-withdrawing groups were tolerant to this reaction in the absence of a ligand and gave trifluorotoluene derivatives in good to high yields.
- Miyagawa, Masamichi,Ishikawa, Taisuke,Shinkai, Kota,Akiyama, Takahiko
-
supporting information
p. 29 - 31
(2019/01/04)
-
- Method for processing fluoride ions in aminobenzotrifluoride
-
The invention discloses a method for processing fluoride ions in aminobenzotrifluoride. The method for processing the fluoride ions in the aminobenzotrifluoride comprises the following steps: taking trifluorotoluene as a raw material, and carrying out mixed acid nitration and catalyzed hydrogeneration reduction under normal pressure to synthesize the aminobenzotrifluoride, wherein a coarse product contains the fluoride ions; mixing and stirring the coarse product of the aminobenzotrifluoride and refined lime proportionally, combining the fluoride ions with calcium ions of calcium oxide to generate calcium fluoride CaF2, and filtering to remove precipitate to obtain trifluoromethylbenzene; drying the trifluoromethylbenzene without the fluoride ions to obtain the refined trifluoromethylbenzene, wherein the main ingredient in the refined lime is calcium oxide CaO. By the mode, the fluoride ions in the trifluoromethylbenzene can be removed effectively, after the fluoride ions are treated once, the content of the fluoride ions can be below 10 ppm generally, and after the fluoride ions are treated twice, the content of the fluoride ions can be below 5 ppm.
- -
-
Paragraph 0016
(2017/06/02)
-
- Preparation method of 3-hydroxyphenyl trifluoromethyl ether
-
The invention provides a preparation method of 3-hydroxyphenyl trifluoromethyl ether. The preparation method comprises the following steps: taking 4-trifluoromethoxyaniline as a raw material; and successively carrying out acetylation, nitrification, deacetylation, deaminizating, reduction and hydrolysis reaction on the 4-trifluoromethoxyaniline to obtain the 3-hydroxyphenyl trifluoromethyl ether. The preparation method is high in yield of products, simple to operate and low in production cost; and industrialization is facilitated.
- -
-
Paragraph 0081; 0086; 0087; 0095; 0101; 0102; 0113; 0114
(2017/09/05)
-
- Method for preparing nilotinib intermediate
-
Disclosed in the present invention is a method for preparing nilotinib intermediate 3-(4-methyl-1H-imidazol-1-yl)-5trifluoromethyl phenylamine (I). The method comprises the following steps: taking trifluorotoluene as an initial material, and preparing the nilotinib intermediate (I) by nitration, bromization, condensation and reduction successively Compared with the prior art, the preparation method has the following advantages: a relatively high yield, the raw materials are easily obtained, a concise process and few side reactions, and is adapted to industrial production, so the development of an economic technology of the bulk drug is pro moted.
- -
-
Paragraph 0027
(2016/11/14)
-
- A method for synthesizing three fluoromethylation aromatic hydrocarbon
-
The invention provides a synthetic method for a trifluoromethyl methylation arene. The trifluoromethyl methylation arene is prepared by reacting a halogenated arene, copper powder, elemental iodine and trifluoroacetic anhydride in an organic solvent under an inert atmosphere protection state. The method has the advantages of being simple and efficient, cheap in raw materials, low in synthetic cost, high in universality and repeatability, and the like, and can be popularized and applied to the fields of the synthesis of trifluoromethyl methylation aromatic derivatives.
- -
-
Paragraph 0039; 0040
(2017/02/09)
-
- Trifluoromethylation of (hetero)aryl iodides and bromides with copper(i) chlorodifluoroacetate complexes
-
A new copper-mediated trifluoromethylation reaction using copper(i) chlorodifluoroacetate complexes as reagents is reported. The complex [L2Cu][O2CCF2Cl] (L = bpy, dmbpy, phen) reacted with (hetero)aryl iodides and bromides in the presence of CsF in DMF at 75 °C to afford the trifluoromethylarenes in good to excellent yields. High compatibility with various chemical functions or (hetero)cycles was also observed in the reaction. A reaction mechanism involving a difluorocarbene intermediate, along with a subsequent formation of a -CF3 anion was proposed.
- Lin, Xiaoxi,Li, Zhengyu,Han, Xiaoyan,Weng, Zhiqiang
-
p. 75465 - 75469
(2016/08/24)
-
- DBU-Promoted Trifluoromethylation of Aryl Iodides with Difluoromethyltriphenylphosphonium Bromide
-
DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide (DFPB) in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P+CF2-, but also converts the difluorocarbene generated from ylide Ph3P+CF2- into trifluoromethyl anion, finally resulting in the trifluoromethylation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.
- Wei, Yun,Yu, Liuying,Lin, Jinhong,Zheng, Xing,Xiao, Jichang
-
p. 481 - 484
(2016/06/01)
-
- Decarboxylative Trifluoromethylating Reagent [Cu(O2CCF3)(phen)] and Difluorocarbene Precursor [Cu(phen)2][O2CCF2Cl]
-
This article describes the new economic decarboxylative trifluoromethylating reagent [Cu(phen)(O2CCF3)] (1; phen=1,10-phenanthroline) and the efficient difluorocarbene precursor [Cu(phen)2][O2CCF2Cl] (2). Treatment of copper tert-butoxide with phen and subsequent addition of trifluoroacetic acid or chlorodifluoroacetic acid afforded air-stable complexes 1 and 2, respectively, which were characterized by X-ray crystallography. The copper(I) ion in 1 is coordinated by a bidentate phen ligand, a monodentate trifluoroacetate group, and a molecule of CH3CN in a distorted tetrahedral coordination geometry. The molecular structure of 2 adopts an ionic form that consists of a [Cu(phen)2]+ cation and a chlorodifluoroacetate anion. Complex 1 reacted with a variety of aryl and heteroaryl halides to form trifluoromethyl (hetero)arenes in good yields. The corresponding Hammett plot exhibited a linear relationship and a reaction parameter (ρ)=+0.56±0.02, which indicated that the trifluoromethylation reaction proceeded via a nucleophilic reactive species. Complex 2 reacts with phenols to produce aryl difluoromethyl ethers in modest-to-excellent yields. Mechanistic investigations revealed that the difluoromethylation reaction proceeds by initial copper-mediated formation of difluorocarbene and subsequent concerted addition of difluorocarbene to the phenol to form a three-center transition state.
- Lin, Xiaoxi,Hou, Chuanqi,Li, Haohong,Weng, Zhiqiang
-
supporting information
p. 2075 - 2084
(2016/02/12)
-
- A simple protocol for Cu-catalyzed protodecarboxylation of (hetero)aromatic carboxylic acids
-
A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials.
- Li, Zhaojie,Fu, Zhengjiang,Zhang, Haixia,Long, Jiao,Song, Yuanyuan,Cai, Hu
-
supporting information
p. 3014 - 3018
(2016/05/09)
-
- An efficient d-glucosamine-based copper catalyst for C-X couplings and its application in the synthesis of nilotinib intermediate
-
d-Glucosamine has been studied for C-N and C-S bond formations via cross-coupling reactions of nitrogen and sulfur nucleophiles with both aryl iodides and bromides. Imidazoles, benzimidazole, indole, pyrrolidine and diphenyl disulfide undergo reactions with aryl halides in the presence of 10 mol% d-glucosamine, 10 mol% CuI, and 2 equiv. of Cs2CO3 in DMSO-H2O at moderate temperature to give the corresponding products in good to excellent yields. Substrates bearing halides, free amino groups, trifluoromethyl and heterocycles were well tolerated. The high water solubility of the ligand enables easy catalyst removal. In addition, the application of this catalytic system for the synthesis of nilotinib intermediate was also successfully demonstrated using commercially available substrates. This journal is
- Wen, Ming,Shen, Chao,Wang, Linfang,Zhang, Pengfei,Jin, Jianzhong
-
p. 1522 - 1528
(2015/02/18)
-
- 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted decomposition of difluorocarbene and the subsequent trifluoromethylation
-
Difluorocarbene derived from various carbene precursors could be effectively decomposed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This decomposition process was successfully applied in the subsequent trifluoromethylation of a variety of (hetero)aryl iodides without the addition of an external fluoride ion. Mechanistic investigation revealed the detailed difluorocarbene conversion process in which the decomposed difluorocarbene is finally transformed into a fluoride ion and carbon monoxide.
- Zheng, Jian,Lin, Jin-Hong,Deng, Xiao-Yun,Xiao, Ji-Chang
-
supporting information
p. 532 - 535
(2015/03/04)
-
- A novel transition metal free [bis-(trifluoroacetoxy)iodo]benzene (PIFA) mediated oxidative ipso nitration of organoboronic acids
-
A mild, convenient and transition metal free methodology for oxidative ipso nitration of diversely functionalized organoboronic acids, including heteroaryl- and alkylboronic acids, has been developed at ambient temperature using a combination of [bis-(trifluoroacetoxy)]iodobenzene (PIFA) - N-bromosuccinimide (NBS) and sodium nitrite as the nitro source. It is anticipated that the reaction proceeds through in situ generation of NO2 and O-centred organoboronic acid radicals followed by the formation of an O-N bond via combination of the said radicals. Finally transfer of the NO2 group to the aryl moiety occurs through 1,3-aryl migration to provide the nitroarenes.
- Chatterjee, Nachiketa,Bhatt, Divya,Goswami, Avijit
-
supporting information
p. 4828 - 4832
(2015/05/05)
-
- A novel method for synthesis of flutamide on the bench-scale
-
Flutamide has been synthesised conveniently in high yields and by an economically beneficial method. Benzotrifluoride was first nitrated and the product was reduced and acylated in one pot in the presence of iron powder and isobutyric acid to produce 3-trifluoroisobutyranilide. Finally, flutamide was produced by further nitration.
- Ghaffarzadeh, Mohammad,Rahbar, Sahar
-
p. 200 - 201
(2014/05/06)
-
- Mechanism of trifluoromethylation of aryl halides with CuCF3and the ortho effect
-
A combined experimental (radical clock, kinetic, Hammett) and computational (DFT, MM) study of the trifluoromethylation reaction of aryl halides with CuCF3 reveals a nonradical mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step. The reaction is second order, first order in each reactant with ΔG? ≈ 24 kcal/mol for PhI (computed ΔG? = 21.9 kcal/ mol). An abrupt change in the gradient on the Hammett plot of log(kR/ kH) versus σp for 11 p-RC6H4I substrates produces two correlations (ρ = +0.69 and +1.83), which is temptingly suggestive of two different reaction pathways. Only one mechanism is operational, however, as advocated by a single linear correlation with σp- (ρ = +0.91), analysis of the experimental ρ values, close similarity of the transition states varying in R and displaying clear signs of -M interactions, and excellent reproduction of the plot by DFT. The long-known yet previously uncomprehended ortho effect has been quantified, for the first time, using the reaction of CuCF3 with a series of o-RC6H4Br: R(kR/kH) = H (1) 2Me (850) 2 (4300) 2H (150 000). With minor contributions from electronic factors, the ortho effect is largely determined by (i) the stabilizing coordination of the o-substituent to Cu in the transition state with the Cu?O distance varying directly with the barrier and (ii) the steric bulk of the o-substituent that raises the ground state free energy of the haloarene (Go ortho - Go H or Go ortho - Go para) by inflicting molecular strain and consequently weakening the Ar-X bond.
- Konovalov, Andrey I.,Lishchynskyi, Anton,Grushin, Vladimir V.
-
supporting information
p. 13410 - 13425
(2015/03/30)
-
- Trifluoromethylation of arenediazonium salts with fluoroform-derived CuCF3 in aqueous media
-
A new protocol has been developed for trifluoromethylation of arenediazonium salts with moisture-sensitive CuCF3 (from fluoroform) in aqueous media. The reaction is governed by a radical mechanism, tolerates a broad variety of functional groups, and is applicable to the synthesis of complex, polyfunctionalized molecules. This journal is the Partner Organisations 2014.
- Lishchynskyi, Anton,Berthon, Guillaume,Grushin, Vladimir V.
-
supporting information
p. 10237 - 10240
(2014/08/18)
-
- Fluoroform synthesis and uses thereof in the preparation of trifluoromethylated compounds
-
The present invention relates to a process to prepare fluoroform (CHF3), notably radio labelled with fluorine-18, comprising a substitution reaction between CHAF2 and a fluoride salt, wherein A represents or as well as a process to prepare a composition comprising copper-based or silver-based trifluoromethylated reagents using notably the fluoroform thus prepared and the use of a composition comprising copper-based trifluoromethylated reagents or a mixture comprising a copper salt and a composition comprising silver-based trifluoromethylated reagents as a trifluoromethylating agent, notably radio labelled with fluorine-18.
- -
-
Paragraph 0112; 0117
(2014/10/15)
-
- DIRECT TRIFLUOROMETHYLATIONS USING TRIFLUOROMETHANE
-
A direct trifluoromethylation method preferably using a trifluoromethane as a fluoro-methylating species. In particular, the present method is used for preparing a trifluoromethylated substrate by reacting a fluoromethylatable substrate with a trifiuoromethylating agent in the presence of an alkoxide or metal salt of silazane under conditions sufficient to trifluoromethylate the substrate; wherein the fluoromethylatable substrate includes chlorosilanes, carbonyl compounds such as esters, aryl halides, aldehydes, ketones, chalcones, alkyl formates, alkyl halides, aryl halides, alkyl borates, carbon dioxide or sulfur.
- -
-
Paragraph 0049
(2014/03/25)
-
- Trifluoromethylation of aryl and heteroaryl halides with fluoroform-derived CuCF3: Scope, limitations, and mechanistic features
-
Fluoroform-derived CuCF3 recently discovered in our group exhibits remarkably high reactivity toward aryl and heteroaryl halides, performing best in the absence of extra ligands. A broad variety of iodoarenes undergo smooth trifluoromethylation with the ligandless CuCF3 at 23-50 C to give the corresponding benzotrifluorides in nearly quantitative yield. A number of much less reactive aromatic bromides also have been trifluoromethylated, including pyridine, pyrimidine, pyrazine, and thiazole derivatives as well as aryl bromides bearing electron-withdrawing groups and/or ortho substituents. Only the most electrophilic chloroarenes can be trifluoromethylated, e.g., 2-chloronicotinic acid. Exceptionally high chemoselectivity of the reactions (no side-formation of arenes, biaryls, and C2F5 derivatives) has allowed for the isolation of a large number of trifluoromethylated products in high yield on a gram scale (up to 20 mmol). The CuCF3 reagent is destabilized by CuX coproduced in the reaction, the magnitude of the effect paralleling the Lewis acidity of CuX: CuCl > CuBr > CuI. While SNAr and SRN1 mechanisms are not operational, there is a well-pronounced ortho effect, i.e., the enhanced reactivity of ortho-substituted aryl halides 2-RC6H4X toward CuCF3. Intriguingly, this ortho-effect is observed for R = NO2, COOH, CHO, COOEt, COCH3, OCH3, and even CH3, but not for R = CN. The fluoroform-derived CuCF3 reagent and its reactions with haloarenes provide an unmatched combination of reactivity, selectivity, and low cost.
- Lishchynskyi, Anton,Novikov, Maxim A.,Martin, Eddy,Escudero-Adan, Eduardo C.,Novak, Petr,Grushin, Vladimir V.
-
p. 11126 - 11146
(2013/12/04)
-
- Recyclable nanoscale copper(I) catalysts in ionic liquid media for selective decarboxylative C-C bond cleavage
-
Here we report the synthesis and application of finely divided Cu 2O nanoparticles (Cu2O-NPs) in the range from 5.5 nm to 8.0 nm in phosphonium ionic liquids as the first recyclable and effective catalytic system for smooth, ligand- and additive-free protodecarboxylation of 2-nitrobenzoic acid as a model substrate and further derivatives. The reactions run with low catalyst loadings and result in quantitative yield in ten consecutive recycling experiments. In addition this system is highly selective towards electron-poor 2-nitrobenzoic acids.
- Kessler, Michael T.,Gedig, Christian,Sahler, Sebastian,Wand, Patricia,Robke, Silas,Prechtl, Martin H. G.
-
p. 992 - 1001
(2013/04/24)
-
- A general strategy for the perfluoroalkylation of arenes and arylbromides by using arylboronate esters and [(phen)CuRF]
-
A versatile method for the synthesis of aryl perfluoroalkanes from arenes and aryl bromides is described. Substituted arenes or aryl bromides are converted in situ to an aryl boronate ester that readily undergoes perfluoroalkylation in air with [(phen)CuRF]. A broad range of aryl bromide substrates were perfluoroalkylated in good yield for the first time. [(phen)CuCF3] is now commercially available and has been prepared on 20g scale. Copyright
- Litvinas, Nichole D.,Fier, Patrick S.,Hartwig, John F.
-
supporting information; scheme or table
p. 536 - 539
(2012/02/16)
-
- Copper-catalyzed oxidative trifluoromethylation of terminal alkynes and aryl boronic acids using (trifluoromethyl)trimethylsilane
-
Trifluoromethylated acetylenes and arenes are widely applicable in the synthesis of pharmaceuticals and agrochemicals. In 2010, our group has reported the copper-mediated oxidative trifluomethylation of terminal alkynes and aryl boronic acids. This method allows a wide range of functional group tolerant trifluoromethylated acetylenes and arenes to be easily prepared. After the preliminary mechanistic studies of the oxidative trifluoromethylation of terminal alkyne, an efficient copper-catalyzed oxidative trifluoromethylation of terminal alkynes and aryl boronic acids has been developed. The catalytic protocol is successfully achieved by adding both the substrate and a portion of CF3TMS slowly using a syringe pump to the reaction mixture.
- Jiang, Xueliang,Chu, Lingling,Qing, Feng-Ling
-
experimental part
p. 1251 - 1257
(2012/03/22)
-
- Copper-catalyzed aromatic trifluoromethylation via group transfer from fluoral derivatives
-
Starting from a readily available fluoral derivative, catalytic aromatic trifluoromethylation has been successfully achieved. A small amount of copper(I) iodide-phenanthroline complex catalyzed the cross-coupling reactions of aryl/heteroaryl iodides with the O-silylated hemiaminal of fluoral (trifluoroacetaldehyde) to provide trifluoromethylated arenes in moderate to high yields.
- Kondo, Hideaki,Oishi, Masahiro,Fujikawa, Kenichi,Amii, Hideki
-
supporting information; experimental part
p. 1247 - 1252
(2011/07/08)
-
- Copper-catalyzed trifluoromethylation of aryl boronic acids using a CF 3+ reagent
-
A copper-catalyzed process for trifluoromethylation of aryl, heteroaryl, and vinyl boronic acids has been developed. The reaction is conducted under mild conditions and shows tolerance to moisture and a variety of functional groups.
- Xu, Jun,Luo, Dong-Fen,Xiao, Bin,Liu, Zhao-Jing,Gong, Tian-Jun,Fu, Yao,Liu, Lei
-
supporting information; experimental part
p. 4300 - 4302
(2011/06/21)
-
- Ethylammonium nitrate (EAN)/Tf2O and EAN/TFAA: Ionic liquid based systems for aromatic nitration
-
Acting as in situ sources of triflyl nitrate (TfONO2) and trifluoroacetyl nitrate (CF3COONO2), the EAN/Tf 2O and EAN/TFAA systems, generated via metathesis in the readily available ethylammonium nitrate (EAN) ionic liquid as solvent, are powerful electrophilic nitrating reagents for a wide variety of aromatic and heteroaromatic compounds. Comparative nitration experiments indicate that EAN/Tf2O is superior to EAN/TFAA for nitration of strongly deactivated systems. Both systems exhibit low substrate selectivity (K T/KB = 5-10) in (Figure presented) between values reported for covalent nitrates and preformed nitronium salts.
- Aridoss, Gopalakrishnan,Laali, Kenneth K.
-
experimental part
p. 8088 - 8094
(2011/11/13)
-
- Copper-mediated trifluoromethylation of arylboronic acids by trifluoromethyl sulfonium salts
-
The ligand-free trifluoromethylation of arylboronic acids with a [Ph 2SCF3]+[OTf]-/Cu(0) system has been carefully investigated. Aryl-, alkenyl- and heteroarylboronic acids with a variety of functional groups were suitable substrates for this reaction. It is suggested that a CuCF3 species is formed under the reaction conditions.
- Zhang, Cheng-Pan,Cai, Ji,Zhou, Chang-Bing,Wang, Xiao-Ping,Zheng, Xing,Gu, Yu-Cheng,Xiao, Ji-Chang
-
supporting information; experimental part
p. 9516 - 9518
(2011/10/02)
-
- Cooperative effect of silver in copper-catalyzed trifluoromethylation of aryl iodides using Me3SiCF3
-
An effective model of cooperative effect of silver for the coppercatalyzed trifluoromethylation of activated and unactivated aryl iodides to trifluoromethylated arenes using Me3SiCF3 was achieved with a broad substrate scope.
- Weng, Zhiqiang,Lee, Richmond,Jia, Weiguo,Yuan, Yaofeng,Wang, Wenfeng,Feng, Xue,Huang, Kuo-Wei
-
experimental part
p. 3229 - 3232
(2011/07/31)
-
- Copper-mediated oxidative trifluoromethylation of boronic acids
-
A copper-mediated oxidative cross-coupling of aryl- and alkenylboronic acids with (trifluoromethyl)trimethylsilane (Me3SiCF3) under mild conditions has been developed. This method allows a wide range of functional group tolerant trifluoromethylated arenes and alkenes to be easily prepared. This oxidative trifluoromethylation has the potential to introduce trifluoromethyl groups into advanced, highly functionalized organic molecules.
- Chu, Lingling,Qing, Feng-Ling
-
supporting information; experimental part
p. 5060 - 5063
(2010/12/29)
-
- Aromatic trifluoromethylation catalytic in copper
-
Cu(i)-diamine complexes were found to catalyse the trifluoromethylation of aryl iodides. In the presence of a small amount of CuX (X = Cl, Br, I) and 1,10-phenanthroline (phen), the cross-coupling reactions of iodoarenes with trifluoromethylsilanes proceeded smoothly to afford trifluoromethylated aromatics in good yields.
- Oishi, Masahiro,Kondo, Hideaki,Amii, Hideki
-
supporting information; experimental part
p. 1909 - 1911
(2009/10/17)
-
- ipso-nitration of arylboronic acids with chlorotrimethylsilane-nitrate salts
-
A mixture of nitrate salt and chlorotrimethylsilane is found to be an efficient regioselective nitrating agent for the ipso-nitration of arylboronic acids to produce the corresponding nitroarenes in moderate to excellent yields. High selectivity, simplicity, and convenience are the key features of the reaction.
- Surya Prakash,Panja, Chiradeep,Mathew, Thomas,Surampudi, Vijayalakshmi,Petasis, Nicos A.,Olah, George A.
-
p. 2205 - 2207
(2007/10/03)
-
- Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
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A new one-pot nitration employing tetramethylammonium nitrate and trifluoromethanesulfonic anhydride in dichloromethane to provide a ready source of the nitronium triflate nitrating agent is presented. Rapid and selective nitration with a variety of aromatic and heteroaromatic substrates is achieved resulting in the synthesis of several novel organic compounds. A distinct advantage is the removal of undesired byproducts by aqueous workup. This very mild nitration permits large-scale syntheses and gives high isolated product yields that often require no further purification. This tetramethylammonium nitrate-based nitration also has been applied to microwave-assisted conditions, and the results with several compounds are outlined.
- Shackelford, Scott A.,Anderson, Mark B.,Christie, Lance C.,Goetzen, Thomas,Guzman, Mark C.,Hananel, Martha A.,Kornreich, Wayne D.,Li, Haitao,Pathak, Ved P.,Rabinovich, Alex K.,Rajapakse, Ranjan J.,Truesdale, Larry K.,Tsank, Stella M.,Vazir, Haresh N.
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p. 267 - 275
(2007/10/03)
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- Electrophilic nitration of aromatics in ionic liquid solvents
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Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Huenig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.
- Laali,Gettwert
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- Photocatalytic reduction of nitroorganics over illuminated titanium dioxide: Electron transfer between excited-state TiO2 and nitroaromatics
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The present study investigates the steady-state photocatalytic reduction of methyl viologen and a suite of monosubstituted nitrobenzenes. Reduction was carried out in deoxygenated, illuminated aqueous slurries of titanium dioxide (Degussa P25) in the presence of a sacrificial electron donor, 2-propanol. Langmuir-Hinshelwood plots were obtained for the reduction of each compound and found to be linear, with an average correlation of 0.98 and with a standard deviation on the correlations of 0.02. The concentration independent rates for nitroaromatic reduction obtained from these plots were normalized against the rate of methyl viologen reduction and the ratio was used to solve for the rate constant of nitroaromatic reduction, assuming a bimolecular model. The assumptions behind this procedure were tested by the use of the Marcus expression. Using the reorganization energy for the reaction as the fitting variable, it was possible to fit the measured rates to the predicted rates with a reorganization energy of 138 kJ/mol.
- Ferry, John L.,Glaze, William H.
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p. 2239 - 2244
(2007/10/03)
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- Chemistry of superacids: 35. * NO2Cl-3MXN systems: Superelectrophilic aprotic nitrating agents for deactivated aromatics
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Superelectrophilic nitration of deactivated aromatics with NO2Cl-3MXn complexes in aprotic nonpolar solvents such as CH2Cl2 makes it possible to obtain the corresponding nitro derivatives in good to almost quantitative yields under mild conditions.
- Olah,Orlinkov,Ramaiah,Oxyzoglou,Prakash
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p. 924 - 927
(2007/10/03)
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- Electrochemical trifluoromethylation of aromatic compounds
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It was shown that the current yield of the products of anodic trifluoromethylation of arenes correlates with the adsorptivity and the rate of electrooxidation of arenes on the surface of a platinum electrode.
- Grinberg,Lundgren,Sterlin,Mysov
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p. 1131 - 1135
(2007/10/03)
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- A novel non-acidic method for the preparation of 2,2,2-trifluoro-1-(3-nitrophenyl)ethanone and 1-nitro-3-trifluoromethylbenzene, versatile starting materials for trifluoromethyl-containing aromatic compounds
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Treatment of 2,2,2-trifluoro-1-phenylethanone (1) and α,α,α-trifluorotoluene (3) with ozone or ozonized air in chlorinated hydrocarbons in the presence of excess nitrogen dioxide and a catalytic amount of iron(III) salt at -10-0°C leads to the respective title nitro compounds 2 and 4 in good to excellent yields. The reaction is clean and rapid, little or no hydrolysis of the trifluoromethyl group being observed during the nitration.
- Suzuki,Tatsumi,Suzuki,Maeda
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p. 1353 - 1354
(2007/10/02)
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- Resonance Electron Capture Rate Constants for Substituted Nitrobenzenes
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We report here a new method for the determination of electron capture (EC) rate constants that utilizes a pulsed electron beam mass spectrometer.The method is first tested by measurements of the known dissociative electron capture rate constants for several halogenated methanes that have been extensively studied by other techniques.The resonance electron capture (REC) rate constants of nitrobenzene (NB) and 23 substituted nitrobenzenes (SNB's) are then determined for the first time at 125 deg C in 10 Torr of methane buffer gas.The SNB's studied here include several sets of closely related structural isomers whose electron affinities (EA's) have been previously determined.It is shown that the REC rate constants of these compounds bear little systematic relationship with the EA's of these compounds.The REC rate constants of the SNB's are also compared with other previously reported characteristics associated with the negative ionization of these compounds, including their entropies of negative ionization, the lifetimes against autodetachment of their initially formed molecular anions, and the rates of autodetachment from electronically excited states of their molecular anions.
- Knighton, W. B.,Mock, R. S.,McGrew, D. S.,Grimsrud, E. P.
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p. 3770 - 3776
(2007/10/02)
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- Aluminum chloride catalyzed nitration of aromatics with sodium nitrate/chlorotrimethyl-silane
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A mixture of sodium nitrate and chlorotrimethylsilane in the presence of anhydrous aluminum trichloride is a convenient nitration system for aromatic compounds. Nitryl chloride is formed as an intermediate in the reactions.
- Olah,Ramaiah,Sandford,Orlinkov,Prakash
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p. 468 - 469
(2007/10/02)
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- Methyl 3-Oxa-ω-fluorosulfonylperfluoropentanoate: a Versatile Trifluoromethylating Agent for Organic Halides
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Methyl 3-oxa-ω-fluorosulfonylperfluoropentanoate FSO2CF2CF2OCF2CO2Me 1, prepared through the reaction of readily available ICF2CF2OCF2CF2SO2F and SO3 followed by MeOH, is a very convenient trifluoromethylating agent; in the presence of copper(I) iodide, 1 not only reacts with vinyl, benzyl allyl, phenyl iodides and bromides, but also with aryl chlorides to give the corresponding trifluoromethyl compounds in moderate to high yield; a probable reaction mechanism is proposed.
- Chen, Qing-Yun,Duan, Jian-Xing
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p. 1389 - 1391
(2007/10/02)
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- Electron Affinities of Naphthalene, Anthracene and Substituted Naphthalenes and Anthracenes
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The determination of electron transfer equilibria A(1-) + B = A + B(1-) in the gas phase, with a pulsed-electron high-pressure mass spectrometer, leads to ΔG10, ΔH10, and ΔS10 values.These can be converted into the free energy, enthalpy and entropy changes, ΔGa0(B), ΔHa0(B) and ΔSa0(B), for the reaction e + B = B(1-), since the corresponding values for the reference compounds A are known.Results were obtained for 18 substituted naphthalenes, anthracene and substituted anthracenes.The results are compared with some theoretical predictions and the corresponding reduction potentials in solution.Rate constants for 13 exoergic electron-transfer reactions were also measured.These were found to be close to the ADO collision rates.
- Heinis, Thomas,Chowdhury, Swapan,Kebarle, Paul
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p. 358 - 365
(2007/10/02)
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- REACTIONS OF ORGANIC COMPOUNDS WITH SF4-HF-HALOGENATING AGENT SYSTEMS VI. REACTIONS OF BENZENE AND ITS DERIVATIVES WITH SF4-HF-Cl2(Br2)
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In the reactions of benzene-carboxylic and -dicarboxylic acids with SF4-HF-Cl2(Br2), apart from the conversion of carboxyls into trifluoromethyl groups, there occurs the halogenation of the benzene ring with the formation of the corresponding chloro- and bromo-containing (trifluoromethyl)- and bis(trifluoromethyl)-benzenes.
- Kunshenko, B. V.,Omarov, V. O.,Muratov, N. N.,Mikhailevskii, S. M.,Yagupol'skii, L. M.
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p. 108 - 112
(2007/10/02)
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- Stabilities of complexes of Br- with substituted benzenes (SB) based on determinations of the gas-phase equilibria Br- + SB = (BrSB)-
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Equilibria involving some forty substituted benzenes (SB) and the bromide ion (SB + Br- = SBBr-) in the gas phase were determined with a pulsed electron, high-pressure mass spectrometer (PHPMS). The resulting -ΔG°1 provide information on the stabilities of the SBBr- complexes. Previous work, involving gas-phase thermochemical data for. X- (CH3O-, F-, C1-, Br-, I-) and quantum chemical calculations, indicate that the most stable SB·X- complexes might have a variety of structures, depending on X- and the nature of the substituents. Thus X- may engage in hydrogen bonding to an aromatic hydrogen atom, or lead to a σ-bonded (Meisenheimer) complex, or form a complex where X- is on an axis perpendicular to the benzene plane. A Taft substituent analysis of the δΔG°1 indicates that Br- and Cl- form aromatic C-H hydrogen-bonded complexes with all singly substituted benzenes. The field effects of the substituents provide the dominant contribution to the bonding in these complexes. Similar conclusions are reached also for the singly substituted nitrobenzenes and Br-. A clearcut analysis of the bonding to Br- when triply substituted benzenes with strongly electron withdrawing substituents like CF3, CN, and NO2 are present could not be obtained. In these cases all three bonding structures mentioned above may have similar stabilities.
- Paul, Gary J. C.,Kebarle, Paul
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p. 1148 - 1154
(2007/10/02)
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- Outer-sphere dissociative electron transfer to organic molecules: A source of radicals or carbanions? Direct and indirect electrochemistry of perfluoroalkyl bromides and iodides
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As an example of the general problem posed in the title, the reduction of CF3Br, CF3I, C6F13I, and C8F17I by outer-sphere heterogeneous (glassy-carbon electrodes) and homogeneous (aromatic anion radicals) reagents is investigated, in aprotic solvents containing tetralkylammonium salts, by cyclic voltammetry and preparative-scale electrolysis. A RF. chemistry is thus triggered in all cases with the exception of CF3Br where a mixed RF./RF- chemistry is obtained by direct electrochemical reduction or by electron transfer from aromatic anion radicals having a close reduction potential. Quantitative analysis of the reduction kinetics of RFX (X = Br, I) and of RF. led to the following conclusions. RFX most likely undergoes a concerted electron-transfer-bond-breaking reduction involving a substantial overpotential (ca. 1.5 V for C-Br and 1.0 V for C-I), mainly governed by the C-X bond dissociation energy. RF. radicals are strongly stabilized by interaction with the solvent but are nevertheless easier to reduce than alkyl radicals on thermodynamical grounds, exhibiting however a high intrinsic barrier of the same order as for alkyl radicals. Unlike alkyl radicals, but similar to aryl radicals, RF. radicals are good H-atom scavengers and do not couple with aromatic anion radicals.
- Andrieux, Claude P.,Gélis, Laurence,Medebielle, Maurice,Pinson, Jean,Savéant, Jean-Michel
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p. 3509 - 3520
(2007/10/02)
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- Process for the halogenation, nitration and fluorination of aromatic derivatives
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A process for the halogenation (bromination or chlorination)/nitration/fluorination of aromatic derivatives substituted by at least one group containing a halogenoalkyl unit. The aromatic derivative is reacted with a halogen and a nitrating agent in liquid hydrofluoric acid. The products obtained are useful as intermediates for the synthesis of compounds having a plant-protecting or pharmaceutical activity.
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