- Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
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A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
- Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
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p. 9561 - 9568
(2021/08/06)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides
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A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also successfully carried out with this metal-free catalytic system in good to excellent yields.
- Gupta, Sampa,Ansari, Alisha,Sashidhara, Koneni V.
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supporting information
(2019/09/07)
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- Ipso-nitration of arylboronic acids with copper nitrate and trifluoroace-tic acid
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An efficient and novel nitrating reagent has been developed for ipso-nitration of arylboronic acids. By using inexpensive and commercially available Cu(NO3)2/CF3COOH as nitrating reagent, various nitroarenes are produced in moderate to excellent yields (51-96%). Advantages of this procedure are the operational simplicity and no need of extra catalyst.
- Wang, Zhu-Qing,Guo, Meng-Ping,Wen, Yong-Ju,Shen, Xiu-Li,Lv, Mei-Yun,Zhou, Xiu-Ling
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p. 891 - 894
(2018/11/06)
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- Synthetic method for 1,5-bis(chloromethyl)-3-fluorobenzene
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The invention discloses a synthetic method for 1,5-bis(chloromethyl)-3-fluorobenzene, which belongs to the field of chemical synthesis. The synthetic method comprises the following steps: adding concentrated sulfuric acid and fuming nitric acid into 3,5-dimethylchlorobenzene and carrying out a reaction in an ice bath so as to obtain 3,5-dimethylnitrobenzene; then adding ethanol and palladium charcoal and introducing hydrogen so as to obtain 3,5-dimethylaniline; allowing 3,5-dimethylaniline and tetrafluoroboric acid to undergo an ice bath and adding a sodium nitrite solution drop by drop; carrying out filtering after completion of addition and drying obtained filter residue; and placing the filter residue in a flask for decomposition, adding water and petroleum ether and carrying out distillation so as to obtain 1,5-bis(chloromethyl)-3-fluorobenzene.
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Paragraph 0007
(2017/02/17)
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- Caged CO2 for the Direct Observation of CO2-Consuming Reactions
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CO2-consuming reactions, in particular carboxylations, play important roles in technical processes and in nature. Their kinetic behavior and the reaction mechanisms of carboxylating enzymes are difficult to study because CO2 is inconvenient to handle as a gas, exists in equilibrium with bicarbonate in aqueous solution, and typically yields products that show no significant spectroscopic differences from the reactants in the UV/Vis range. Here we demonstrate the utility of 3-nitrophenylacetic acid and related compounds (caged CO2) in conjunction with infrared spectroscopy as widely applicable tools for the investigation of such reactions, permitting convenient measurement of the kinetics of CO2 consumption. The use of isotopically labeled caged CO2 provides a tool for the assignment of infrared absorption bands, thus aiding insight into reaction intermediates and mechanisms.
- Lommel, Katharina,Sch?fer, Gabriela,Grenader, Konstantin,Ruland, Christoph,Terfort, Andreas,M?ntele, Werner,Wille, Georg
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p. 372 - 380
(2013/08/24)
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- Copper-catalyzed nitration of arylboronic acids with nitrite salts under mild conditions: An efficient synthesis of nitroaromatics
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Copper-catalyzed nitration of arylboronic acids has been developed with nitrite salts as nitrating agent under mild conditions. This process provides an efficient and practical method for the synthesis of nitro aromatics, due to its simple experimental procedure and its use of convenient and inexpensive copper catalyst.
- Yan, Guobing,Zhang, Ling,Yu, Jian
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experimental part
p. 133 - 137
(2012/07/28)
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- Green and controllable metal-free nitrification and nitration of arylboronic acids
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A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to the traditional nitration protocols.
- Wang, Shuai,Shu, Chun Chun,Wang, Tao,Yu, Jian,Yan, Guo Bing
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scheme or table
p. 643 - 646
(2012/08/07)
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- Pd-catalyzed conversion of aryl chlorides, triflates, and nonaflates to nitroaromatics
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(Chemical Equation Presented) An efficient Pd catalyst for the transformation of aryl chlorides, triflates, and nonaflates to nitroaromatics has been developed. This reaction proceeds under weakly basic conditions and displays a broad scope and excellent
- Fors, Brett P.,Buchwald, Stephen L.
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scheme or table
p. 12898 - 12899
(2009/12/07)
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- Electrophilic Aromatic Nitration Using a Mixed Catalyst of Lithium, Molybdenum, Ytterbium on Silica Gel
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A novel mixed catalyst of LiClO4 (15% w/w), Yb(OPf)3 (15% w/w, Pf = perfluorooctanesulfonyl), MoO3 (15% w/w) on silica gel for electrophilic aromatic nitration reaction has been explored. The nitration reactions were accomplished by this mixed catalyst and nitric acid under solvent-free conditions. Moreover, the mixed catalyst can be easily recovered from the aqueous layer by heating in an oven and reused for the next nitration reaction.
- Shi, Min,Cui, Shi-Cong
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p. 1329 - 1333
(2007/10/03)
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- Reductive coupling of nitrobenzene or nitrobenzenes substituted on the nucleus to give the corresponding azobenzenes and azoxybenzenes by means of redox catalysts
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Nitrobenzene or a nitrobenzene substituted on the nucleus is subjected to reductive coupling to give the corresponding azobenzene and azoxybenzene under heterogeneous catalysis with substantial avoidance of overreduction to aniline derivatives by means of a redox catalyst in its reduced or partly reduced form, the redox catalyst containing at least one active metal component capable of a change of oxidation state.
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- Cobalt schiff base complex-catalyzed oxidation of anilines with tert-butyl hydroperoxide
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Cobalt Schiff base complexes [Co(SB)] catalyze the oxidation of anilines (1) with tert-butyl hydroperoxide to give nitrobenzenes 2 and 4-(tert-butylperoxy)-2,5-cyclohexadien-1-imine derivatives 3 in yield distributions depending on the substitution mode of the substrate. 4-Alkyl- and 4-aryl-2,6-di-tert-butylanilines gave mixtures of 2 and 3, where the higher the bulkiness of the 4-substituent, the higher the yield of 2. With 2,4,6-trimethylaniline, the ratio of oxidations of the nitrogen and C-4 atoms was almost the same; but a hydrolyzed product 5 of the imine was obtained. 2,4,6-Triphenylaniline gave only 2. Nitrobenzene derivatives were also obtained from 2,6-dialkylanilines and 4-substituted anilines. The catalytic activity of Co(SB) depended on the nature of the SB ligand: the formal potential E° and steric factors seem to affect the reaction rate. Kinetic studies showed that the key step may involve hydrogen abstraction from the aniline, presumably by t-BuO? generated from homolytic decomposition of initially formed CoIII(SB)(OO-t-Bu). A precursor of 2 was found to be the nitrosobenzene derivative.
- Foerster, Stefan,Rieker, Anton,Maruyama, Kazushige,Murata, Kunihiko,Nishinaga, Akira
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p. 3320 - 3326
(2007/10/03)
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- Sulfuric acid on silica-gel: An inexpensive catalyst for aromatic nitration
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Solid acidic catalysts made of sulfuric acid supported on silica-gel and their application to the nitration of aromatics with nitric acid and isopropyl nitrate are described. Substrates with very different levels of activation were investigated. Methods to overcome the poisoning produced by water and to tune the catalysts activity according to the reactivity of the substrate are outlined.
- Riego, Juan M.,Sedin, Zeno,Zaldivar, Jose M.,Marziano, Nunziata C.,Tortato, Claudio
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p. 513 - 516
(2007/10/02)
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- Efficient Catalysis of Hydrodediazoniations in Dimethylformamide
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For hydrodediazoniations (the replacement of a diazo group by hydrogen) in DMF, several substances act as catalysts through their ability to serve as electron donors and initiate free-radical reactions.A general procedure has been developed in which FeSO4 speeds the conversion and leads to higher yields.Trapping experiments demonstrated the presence of free-radical intermediates.N,N-Dimethylacetamide was found to rival DMF as a source of hydrogen atoms.
- Wassmundt, Frederick W.,Kiesman, William F.
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p. 1713 - 1719
(2007/10/02)
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- Deuteriodediazoniation: A general method for the replacement of a diazonium group by deuterium
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Aromatic amino groups are replaced with deuterium via a diazonium salt intermediate. Dimethylformamide-d7 is the deuterium donor in this mild replacement method that yields aromatic-d1 products in high isotopic purity. The presence of methyl groups lowers the isotopic purity of the products.
- Wassmundt,Kiesman
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p. 281 - 288
(2007/10/02)
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- Oxidation of Aromatic Amines with Hydrogen Peroxide Catalyzed by Cetylpyridinium Heteropolyoxometalates
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Various substituted anilines 1 were selectively converted into the corresponsing nitrosobenzenes 2 or nitrobenzenes 3 by oxidation with aqueous hydrogen peroxide catalyzed by heteropolyoxometalates.The oxidation of anilines 1 with 35percent H2O2 catalyzed by peroxotungstophosphate (PCWP) at room temperature in chloroform under two-phase conditions afforded nitrosobenzene 2 with high selectivity.When the same reactions were carried out at higher temperature (e.g., refluxing chloroform), nitrobenzenes 3 were obtained in good yields.The oxidation of aniline (1a) with dilute H2O2 catalyzed by PCWP (2 wtpercent) in an aqueous medium produced azoxybenzene (4a) with high selectivity.Phenylazoxyalkanes 7 were prepared by the first direct cooxidation of 1a in the presence of primary aliphatic amines 6.For example, the oxidation of a 1:2 mixture of 1a and hexylamine (6b) with 35percent H2O2 (6 equiv) in the presence of PCWP produced phenylazoxyhexane (7b) along with a small amount of 4a (8percent).The reaction path for the conversion of anilines to azoxy-, nitroso-, and nitrobenzenes is described.
- Sakaue, Sigeki,Tsubakino, Takashi,Nishiyama, Yutaka,Ishii, Yasutaka
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p. 3633 - 3638
(2007/10/02)
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- A CONVENIENT SRN1 SYNTHESIS OF AROMATIC NITRILES FROM DIAZONIUM SALTS VIA DIAZOSULFIDES
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Properly substituted diazosulfides XC6H4-N=N-SPh (1) (either isolated or generated in situ from arenediazonium tetrafluoroborates and sodium benzenethiolate) react with tetrabutylammonium cyanide, in Me2SO under photon or electron stimulation, leading to nitriles XC6H4CN (2).Satisfactory yields of 2, comparable with those of the Sandmeyer reaction, are obtained when X= 3- or 4-CF3, 2-, 3-, or 4-CN, 4-F, 4-MeCO, 3-MeO, 4-NO2, 4-PhCO, and 4-PhSO2.For different reasons, the reaction practically fails as a useful nitrile synthesis when X= H, 4-MeO, 2-, or 3-NO2.The collected evidences agree well with the intervention of an SRN1 mechanism to which diazosulfides 1, given their easy reducibility followed by a prompt fragmentation of the C-N and N-S bonds, are convenient participating substrates.An important consequence of the mechanism involved is the behaviour of bromo and chloro derivatives (1: X= Br, Cl) which lead, through the contemporaneous introduction of two cyano functionalities, to more than satisfactory yields of the corresponding dicyanobenzenes.
- Petrillo, Giovanni,Novi, Marino,Garbarino, Giacomo,Dell'erba, Carlo
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p. 4625 - 4634
(2007/10/02)
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- Aromatic Substitution. 48. Boron Trifluoride Catalyzed Nitration of Aromatics with Silver Nitrate in Acetonitrile Solution
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Benzene, alkylbenzenes, halobenzenes, and anisole were nitrated with silver nitrate/boron trifluoride in acetonitrile solution.Correlation of competitive rates with ?- and ?-complex stabilities indicated that the transition state of highest energy lies relatively early on the reaction coordinate.Data indicate that nitrations occur via a polarized complex of the nitrating agent, with the catalyst undergoing nucleophilic displacement by the aromatic substrate.
- Olah, George A.,Fung, Alexander P.,Narang, Subhash C.,Olah, Judith A.
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p. 3533 - 3537
(2007/10/02)
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- Anisotropy Effects of Conjugated Cyclic Systems, IV. 1H-NMR Spectra of Mesityl-Substituted 2,6-Dimethylbenzene Derivatives
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The effect of very different substituents X on the chemical shift differences Δδ of the o- and p-methyl group 1H NMR signals of 4'-X-substituted 2,2',4,6,6'-pentamethylbiphenyl derivatives is +/- 0.045 ppm only.In comparison with X = H (0.47 ppm) electron attracting substitutents like X = N2+ increase Δδ values up to 0.53, X = CN and NO2 up to 0.52 ppm; electron releasing groups X = OH, NH2 reduce Δδ down to 0.45 and OCH3 to 0.44 ppm.Even in the 2-mesitylsubstituted 1,3,5,-trimethyltropylium ion (2) Δδ rises only up to 0.54 ppm.
- Brotzeller, Uwe,Nyitrai, Jozsef,Musso, Hans
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p. 3610 - 3620
(2007/10/02)
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