- Metal-free Transformations of Nitrogen-Oxyanions to Ammonia via Oxoammonium Salt
-
Transformations of nitrogen-oxyanions (NOx?) to ammonia impart pivotal roles in sustainable biogeochemical processes. While metal-mediated reductions of NOx? are relatively well known, this report illustrates proton-assisted transformations of NOx? anions in the presence of electron-rich aromatics such as 1,3,5-trimethoxybenzene (TMB?H, 1 a) leading to the formation of diaryl oxoammonium salt [(TMB)2N+=O][NO3?] (2 a) via the intermediacy of nitrosonium cation (NO+). Detailed characterizations including UV/Vis, multinuclear NMR, FT-IR, HRMS, X-ray analyses on a set of closely related metastable diaryl oxoammonium [Ar2N+=O] species disclose unambiguous structural and spectroscopic signatures. Oxoammonium salt 2 a exhibits 2 e? oxidative reactivity in the presence of oxidizable substrates such as benzylamine, thiol, and ferrocene. Intriguingly, reaction of 2 a with water affords ammonia. Perhaps of broader significance, this work reveals a new metal-free route germane to the conversion of NOx to NH3.
- Anju, Balakrishnan S.,Kundu, Subrata,Mondal, Aditesh,Sahana, Tuhin
-
supporting information
p. 20661 - 20665
(2021/08/25)
-
- New diarylsulfonamide inhibitors of Leishmania infantum amastigotes
-
New drugs against visceral leishmaniasis with mechanisms of action differing from existing treatments and with adequate cost, stability, and properties are urgently needed. No antitubulin drug is currently in the clinic against Leishmania infantum, the causative agent of visceral leishmaniasis in the Mediterranean area. We have designed and synthesized a focused library of 350 compounds against the Leishmania tubulin based on the structure-activity relationship (SAR) and sequence differences between host and parasite. The compounds synthesized are accessible, stable, and appropriately soluble in water. We assayed the library against Leishmania promastigotes, axenic, and intracellular amastigotes and found 0, 8, and 16 active compounds, respectively, with a high success rate against intracellular amastigotes of over 10%, not including the cytotoxic compounds. Five compounds have a similar or better potency than the clinically used miltefosine. 14 compounds showed a host-dependent mechanism of action that might be advantageous as it may render them less susceptible to the development of drug resistance. The active compounds cluster in five chemical classes that provide structure-activity relationships for further hit improvement and facilitate series development. Molecular docking is consistent with the proposed mechanism of action, supported by the observed structure-activity relationships, and suggests a potential extension to other Leishmania species due to sequence similarities. A new family of diarylsulfonamides designed against the parasite tubulins is active against Leishmania infantum and represents a new class of potential drugs with favorable cost, stability, and aqueous solubility for the treatment of visceral leishmaniasis (VL). These results could be extended to other clinically relevant species of Leishmania spp.
- González, Myriam,Alcolea, Pedro José,álvarez, Raquel,Medarde, Manuel,Larraga, Vicente,Peláez, Rafael
-
-
- Methoxy and bromo scans on N-(5-methoxyphenyl) methoxybenzenesulphonamides reveal potent cytotoxic compounds, especially against the human breast adenocarcinoma MCF7 cell line
-
Thirty seven N-(5-methoxyphenyl)-4-methoxybenzenesulphonamide with methoxy or/and bromo substitutions (series 1-4) and with different substituents on the sulphonamide nitrogen have been synthesised. 21 showed sub-micromolar cytotoxicity against HeLa and HT-29 human tumour cell lines, and were particularly effective against MCF7. The most potent series has 2,5-dimethoxyanilines, especially the 4-brominated compounds 23–25. The active compounds inhibit microtubular protein polymerisation at micromolar concentrations, thus pointing at tubulin as the target. Co-treatment with the MDR inhibitor verapamil suggests that they are not MDR substrates. Compound 25 showed nanomolar antiproliferative potency. It severely disrupts the microtubule network in cells and arrests cells at the G2/M cell-cycle phase, thus confirming tubulin targeting. 25 triggered apoptotic cell death, and induced autophagy. Docking studies suggest binding in a distinct way to the colchicine site. These compounds are promising new antitumor agents acting on tubulin.
- Medarde, Manuel,González, Myriam,González-Sarmiento, Rogelio,Ovejero-Sánchez, María,Peláez, Rafael,Vicente-Blázquez, Alba
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p. 1029 - 1047
(2021/06/16)
-
- Electrochemical Nitration with Nitrite
-
Aromatic nitration has tremendous importance in organic chemistry as nitroaromatic compounds serve as versatile building blocks. This study represents the electrochemical aromatic nitration with NBu4NO2, which serves a dual role as supporting electrolyte and as a safe, readily available, and easy-to-handle nitro source. Stoichiometric amounts of 1,1,1-3,3,3-hexafluoroisopropan-2-ol (HFIP) in MeCN significantly increase the yield by solvent control. The reaction mechanism is based on electrochemical oxidation of nitrite to NO2, which initiates the nitration reaction in a divided electrolysis cell with inexpensive graphite electrodes. Overall, the reaction is demonstrated for 20 examples with yields of up to 88 %. Scalability is demonstrated by a 13-fold scale-up.
- Blum, Stephan P.,Nickel, Christean,Sch?ffer, Lukas,Karakaya, Tarik,Waldvogel, Siegfried R.
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p. 4936 - 4940
(2021/10/25)
-
- Nitration method for aryl phenol or aryl ether derivative
-
The invention relates to a nitration method for an aryl phenol or aryl ether derivative. The method comprises the steps of stirring an aryl phenol or aryl ether compound, nitrate, trimethylchlorosilane (TMSCl) and a copper salt in an acetonitrile solution in air at room temperature, simultaneously, monitoring extent of reaction through a TLC dot plate, removing a solvent from a mixture by a rotaryevaporator after a substrate is consumed completely, and carrying out purification through a silica-gel column, thereby obtaining a nitroolefin derivative. Meanwhile, the selective mono-nitration orbis-nitration of the substrate can be achieved through controlling equivalent weight of the nitrate. Compared with the prior art, the nitration method disclosed by the invention has the advantages that the consumption of strong-acid substances is avoided, the reaction conditions are mild, the yield is high, the applicable range of the substrate is wide, reaction activity is free of obvious attenuation after an amplified reaction, and an excellent yield is still obtained, so that the method has an obvious industrial application value.
- -
-
Paragraph 0044-0049; 0050-0055; 0089-0091
(2020/01/03)
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- 3-(Ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium cation: A green alternative to tert-butyl nitrite for synthesis of nitro-group-containing arenes and drugs at room temperature
-
Due to their remarkable properties, task-specific ionic liquids have turned out to be progressively popular over the last few years in the field of green organic synthesis. Herein, for the first time, we report that a new task-specific nitrite-based ionic liquid such as 3-(ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium bis(trifluoromethanesulfonyl)imides (TS-N-IL) derived from biodegradable ethyl nicotinate indeed acted as an efficient and eco-friendly reagent for the synthesis of highly valuable nitroaromatic compounds and drugs including nitroxynil, tolcapone, niclofolan, flutamide, niclosamide and nitrazepam. The bridging of an ionic liquid with nitrite group not only increases the yield and rate of direct C[sbnd]N bond formation reaction but also allows easy product separation and recyclability of a byproduct. Nonvolatile nature, easy synthesis, merely stoichiometric need and mildness are a portion of the extra focal points of TS-N-IL while contrasted with tert-butyl nitrite an outstanding and highly-flammable reagent utilized largely in organic synthesis.
- Chaudhary, Renu,Natarajan, Palani,Rani, Neetu,Sakshi,Venugopalan, Paloth
-
supporting information
(2019/12/30)
-
- Direct nitration method of electron-enriched aromatic hydrocarbons
-
The invention discloses a direct nitration method of electron-enriched aromatic hydrocarbons, and belongs to the field of organic synthesis. The direct nitration method is a novel green free radical nitration method; aromatic hydrocarbons are taken as raw materials, acetonitrile, dichloromethane, chloroform, or acetone is taken as a reaction solvent, at room temperature conditions, the raw materials and green nitration reagent tert-butyl nitrite (TBN) are subjected to free radical nitration so as to obtain nitro-aromatic compounds. According to the direct nitration method, no metal is adoptedin reaction, tert-butyl nitrite is directly adopted in nitration reaction. Electron-donating groups such as OMe are introduced, the electron density of aromatic compounds is increased, the nitration reaction possibility is increased. The using amount of tert-butyl nitrite is reduced; only a product and tert-butyl alcohol are generated, environment pollution is reduced. The direct nitration methodis promising in application prospect in the field of nitro-aromatic compound synthesis, green nitration is realized, and a novel idea is provided for large-scale industrialized nitro-aromatic compoundproduction.
- -
-
Paragraph 0033-0035; 0038; 0041; 0044
(2018/10/02)
-
- Mechanical force under the action of the nitration of aromatic compounds of nitrate method (by machine translation)
-
The invention discloses a mechanical force under the action of the nitration of aromatic compounds of nitrate method. The invention provides a method for preparing aromatic nitro compounds, comprising the following steps: under the action of mechanical force, aromatic compound with a metal nitrate or its hydrate by the nitration reaction, to obtain the aromatic nitro compound; the mechanical fastener is machinery offers can cause material physical and/or chemical nature of the change of the external force. The mechanical force can be compression, shear, impact, friction, tensile, bending and vibration of any kind. The invention has the following advantages: without the use of any solvent, thereby avoiding the waste liquid produced; and without the use of the acidic substance, the reaction is complete after treatment is simple, without any damage to the apparatus; a very high conversion and selectivity, can be applied to the nitration of conventional aromatic compound. (by machine translation)
- -
-
Paragraph 0060; 0061
(2018/09/11)
-
- Rapid aerobic iodination of arenes mediated by hypervalent iodine in fluorinated solvents
-
Arenes are rapidly converted to the corresponding iodides by aerobic oxidative iodination at room temperature by treatment with iodine and catalytic quantities of nitrous acid in a fluorinated solvent. Dichloroiodic acid is proposed as the actual iodination reagent.
- Iskra, Jernej,Murphree, S. Shaun
-
supporting information
p. 645 - 648
(2017/01/28)
-
- Nucleophilic Nitration of Arynes by Sodium Nitrite and its Multicomponent Reaction Leading to Double-Functionalized Arenes
-
An unusual nucleophilic nitration of arynes by NaNO2 in the presence of water has been developed, and the concept was further demonstrated to accomplish a double functionalization of arynes using a multicomponent reaction protocol to synthesize pharmaceutically important (2-nitrophenyl)methanol derivatives. Such substitution ortho to -NO2 is difficult by other means. The reaction conditions are mild and avoid the use of strong acids, expensive transition metal catalysts, and additives.
- Dhokale, Ranjeet A.,Mhaske, Santosh B.
-
supporting information
p. 3010 - 3013
(2016/07/06)
-
- NITRATING AGENT AND METHOD FOR PRODUCING NITRO COMPOUND
-
PROBLEM TO BE SOLVED: To provide a method for producing a nitrating agent not necessarily requiring the use of a large quantity of acid, and a method for producing a nitro compound. SOLUTION: Provided is a nitrating agent including: an inorganic porous member; and a nitrate carried on the inorganic porous member. As the inorganic porous member, a silica gel can be given. As the nitrate, an alkaline-earth metal nitrate can be given. In the method for producing a nitro compound, the nitrating agent and an organic compound are contacted, and heating is performed. As the organic compound, an aromatic compound can be given. The temperature upon the heating is preferably set in 70 to 170°C. COPYRIGHT: (C)2015,JPOandINPIT
- -
-
Paragraph 0027-0029
(2017/01/02)
-
- Synthesis of aryl ethers from benzoates through carboxylate-directed C-H-activating alkoxylation with concomitant protodecarboxylation
-
One in, one out: In the presence of a copper/silver bimetallic catalyst system, aromatic carboxylate salts undergo ortho C-H alkoxylation with concomitant loss of the carboxylate directing group in a protodecarboxylation step (see scheme, FG=functional group). This process provides a convenient synthetic access to the important class of aromatic ethers from widely available carboxylic acids. Copyright
- Bhadra, Sukalyan,Dzik, Wojciech I.,Goo?en, Lukas J.
-
p. 2959 - 2962
(2013/04/10)
-
- Hydrogen bonded arylamide-linked cholesteryl dimesogenic liquid crystals: A study of the length and side chain effects
-
Dimesogenic compounds 1a-c, 2a-i, and 3, that are composed of a hydrogen bonding-induced straight arylamide spacer and two appended cholesterol groups, have been designed and synthesized. The backbones of the rigid spacers of 1a-c, 2a-i, and 3 contain one, three, and five benzene units, which bear two, six, and ten alkoxyl (methoxyl, n-octoxyl, or n-dodecoxyl) groups, respectively. The thermal and optical properties of the compounds are investigated by using the differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (PXRD) analysis. It is revealed that 1a-c exhibit one or two liquid crystalline (LC) phases, 2a-i exhibit no, one or two LC phases, while 3 exhibits one LC phase in a wide temperature range. Generally, the more and longer alkoxyl chains facilitate the formation of the LC phases at low temperature. Notably, compound 2g, which bears two methoxyl and four dodecoxyl groups, displays a blue-red color change during both the heating and cooling cycle. The result illustrates that dimesogens with large rigid spacers can exhibit different LC phases when long aliphatic chains are appended to balance the strong stacking of the rigid backbones.
- Wang, Gui-Tao,Zhao, Xin,Li, Zhan-Ting
-
scheme or table
p. 48 - 57
(2011/03/17)
-
- Aromatic nitration in liquid Ag0.51K0.42Na 0.07NO3
-
(Figure Presented) Aromatic molecules have a strong affinity for silver(I) and dissolve to a limited extent in Ag0.51K0.42Na 0.07NO3, a low-melting eutectic mixture of silver, potassium, and sodium nitrates. Aromatic nitration in this inorganic ionic liquid leads to products which arise from nonelectrophilic substitution pathways.
- Mascal, Mark,Yin, Lunxiang,Edwards, Ross,Jarosh, Michael
-
p. 6148 - 6151
(2008/12/22)
-
- Zeolite H-Y-supported copper(II) nitrate: A simple and effective solid-supported reagent for nitration of phenols and their derivatives
-
Highly regiospecific mononitration of phenols and substituted phenols is accomplished by employing copper(II) nitrate supported on a catalytic amount of zeolite H-Y in a solid state. Copyright Taylor & Francis Group, LLC.
- Lalitha,Sivakumar
-
p. 1745 - 1752
(2008/09/20)
-
- Nitric acid in the presence of P2O5 supported on silica gel - A useful reagent for nitration of aromatic compounds under solvent-free conditions
-
A variety of aromatic compounds are nitrated to parent nitro aromatic compounds under solvent-free conditions using 65% nitric acid in the presence of P2O5 supported on silica gel is described. This methodology is useful for nitration of activated and deactivated aromatic rings.
- Hajipour, Abdol Reza,Ruoho, Arnold E.
-
p. 8307 - 8310
(2007/10/03)
-
- Nitration of aromatic compounds by Zn(NO3)2· 2N2O4 and its charcoal-supported system
-
Zn(NO3)2·N2O4 and its charcoal supported system were found to be efficient nitrating agents. Mononitration of aromatic compounds such as benzene, alkyl benzenes, halobenzenes, nitrobenzene, anisol, and the highly selective mono-, di-, and trinitration of phenol, and dinitraion of substituted phenols were also performed in the presence of these reagents.
- Iranpoor, Nasser,Firouzabadi, Habib,Heydari, Reza,Shiri, Morteza
-
p. 263 - 270
(2007/10/03)
-
- Highly efficient catalytic nitration of phenolic compounds by nitric acid with a recoverable and reusable Zr or Hf oxychloride complex and KSF
-
Phenolic compounds can be nitrated with 60% nitric acid (1.2 equiv.) in the presence of catalytic amounts of a Zr or Hf oxychloride complex and montmorillonite KSF to give the corresponding nitrated products in good yields in a heterogeneous catalytic system. The co-catalyst and montmorillon ite can be easily recovered and reused in the next batch of nitration. This is a practical process for the nitration of phenolic compounds in a clean way. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Shi, Min,Cui, Shi-Cong,Yin, Wan-Po
-
p. 2379 - 2384
(2007/10/03)
-
- A fast and mild method for nitration of aromatic rings
-
The use of benzyltriphenylphosphonium nitrate (PhCH2Ph 3P+NO3-) (BTPPN) as a useful reagent for nitration aromatic compounds in the presence of methanesulfonic anhydride under solvent-free conditions is described. This methodology is useful for nitration of activated aromatic rings.
- Hajipour, Abdol R.,Ruoho, Arnold E.
-
p. 221 - 226
(2007/10/03)
-
- A mild and efficient method for the mononitration of aromatic compounds by cerium (III) ammonium nitrate in acetic anhydride
-
A mild and efficient method for the mononitration of aromatic and olefinic compounds is described. This method is especially useful for active substrates.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
-
p. 497 - 499
(2007/10/03)
-
- A New Method for Nitration of Phenolic Compounds
-
Phenolic compounds can be nitrated by 65% nitric acid in the presence of catalytic amounts of montmorillonite KSF and bismuth(III) nitrate to give the corresponding nitrated products in good yields in a heterogeneous phase. The co-catalyst of KSF and Bi(NO3)3 can be easily recovered and reused in the next batch of nitration.
- Shi, Min,Cui, Shi-Cong
-
p. 1197 - 1202
(2007/10/03)
-
- Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
-
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.
-
p. 267 - 275
(2007/10/03)
-
- Novel process for generating useful electrophiles from common anions using Selectfluor fluorination agent
-
In the present work, the electrophile equivalents C1+, Br+, SCN+, and NO2+ are generated from their respective sodium, potassium, and in some cases ammonium salts (M+X-) by reaction with Selectfluor electrophilic fluorination agent in acetonitrile solution at room temperature. These generated electrophilic species subsequently react in situ with a variety of aromatic substrates containing one or more substituent groups including H, F, C1, CH3, COOH, C(O)CH3, NO2, and OR′ and NR′R″ where R′ and R″ are H or CH3. The resulting substitution products are, in most cases, isolable as pure compounds in high yield. Variations in the process include the use of other anions, electrophilic fluorination agents, and solvents.
- Syvret, Robert G.,Butt, Kathleen M.,Nguyen, Tung P.,Bulleck, Victoria L.,Rieth, Ryan D.
-
p. 4487 - 4493
(2007/10/03)
-
- A mild one-pot procedure for the polynitration of activated arenes. Convenient preparation of dinitro- and trinitrodialkoxybenzenes
-
When first treated with an excess of nitrogen dioxide alone and then in the presence of ozone at low temperature, dialkoxybenzenes are smoothly and stepwise polynitrated in a one-pot manner to afford the corresponding dinitro or trinitro derivatives in good yield.
- Nose,Suzuki
-
p. 1539 - 1542
(2007/10/03)
-
- The dichotomy between nitration of substituted 1,4-dimethoxybenzenes and formation of corresponding 1,4-benzoquinones by using nitric and sulfuric acid
-
Various alkyl-substituted p-dimethoxybenzenes (ArH) react readily With nitric acid and sulfuric to form nitroproducts (ARNO2). When the nitric acid is used in excess, the nitro-product react via either nitration to dinitrocompound (Ar(NO2)2) or via oxidative demethylation to nitro-p- quinone (Q). As such, the competition between the nitration, polynitration and oxidative dealkylation is effectively modulated by the added nitric acid and the alkyl-substituted p-dimethoxybenzenes.
- Waterlot,Haskiak,Couturier
-
p. 106 - 107
(2007/10/03)
-
- Nitration of electron-rich aromatic compounds by cerium ammonium nitrate coated on silica
-
Treatment of electron-rich aromatic derivatives with cerium (IV) ammonium nitrate coated on silica (CANSio2) affords nitro aromatic compounds. The scope and the limitation of this reaction are discussed.
- Grenier, Jean-Luc,Catteau, Jean-Pierre,Cotelle, Philippe
-
p. 1201 - 1208
(2007/10/03)
-
- The nitration of electron-rich aromatics
-
The successful mononitration of a variety of electron-rich aromatic substrates is reported, employing either nitronium tetrafluoroborate or 'claycop' as the nitrating agent. Dinitration of four of the substrates was achieved when employing nitronium tetrafluoroborate. Several of the products have previously been prepared only by indirect methods.
- Dwyer,Holzapfel
-
p. 7843 - 7848
(2007/10/03)
-
- Thermal and photochemical decomposition pathways of trinitromethylarenes. part II. The effects of ethanol on the photolysis reactions of some alkoxy- and dialkoxyarenes in the presence of tetranitromethane. enhancement of adduct and trinitromethyl substitution product formation
-
The photolysis of the charge transfer (CT) complex of tetranitromethane with 1-methoxynaphthalene, 1,4-dimethoxybenzene, 1,2-dimethoxybenzene, 1,2-methylenedioxybenzene or 2-methylanisole is reported for dichloromethane, acetonitrile, dichloromethane-ethanol and acetonitrile-ethanol solvent systems. The effects of adding ethanol (8% v/v ? 1.4 mol dm-3) to dichloromethane or acetonitrile as reaction solvents include: (i) the stabilization of alkoxytrinitro-methylarenes, thus reducing their normal tendency for decomposition according to ArC (NO2)3→ArCOOH→ArNO2, (ii) a reduction in the nucleophilicity of trinitromethanide ion, and (iii) changes in the regioselectivity of trinitromethanide ion attack on the radical cations of alkoxyaromatic compounds away from attack ipso to the alkoxy substituent. Adducts are also stabilized, as shown by the photolysis of the CT complex of 1,4-dimethoxybenzene-tetranitromethane in dichloromethane-ethanol (8% v/v) which gives the epimeric 1,4-dimethoxy-3-nitro-6-trinitromethylcyclohexa-1,4-dienes and 1,4-dimethoxy-2-trinitromethylbenzene, in addition to 1,4-dimethoxy-2-nitrobenzene. The adducts are detected also among the products of photolysis reactions in neat dichloromethane or acetonitrile. Acta Chemica Scandinavica 1997.
- Butts, Craig P.,Eberson, Lennart,Hartshorn, Michael P.,Persson, Ola
-
p. 718 - 732
(2007/10/03)
-
- Iron(III)-catalysed nitration of non-activated and moderately activated arenes with nitrogen dioxide-molecular oxygen under neutral conditions
-
In the presence of molecular oxygen and a catalytic amount of tris(pentane-2,4-dionato)iron(III), non-activated and moderately activated arenes, which include alkylbenzenes, halogenobenzenes, phenolic ethers, naphthalene and derivatives, can be nitrated with nitrogen dioxide at ice-bath temperature or below to give the corresponding nitro derivatives in fair to good yields. An electron-transfer mechanism has been proposed, where an activated NO2-FeIII complex plays a key role in the cyclic process for converting arenes into nitroarenes.
- Suzuki, Hitomi,Yonezawa, Shuji,Nonoyama, Nobuaki,Mori, Tadashi
-
p. 2385 - 2389
(2007/10/03)
-
- Convenient Nitration of Anisole and its Derivatives using an NO-O2 System
-
Anisole and its derivatives are regioselectively nitrated by use of nitrogen monoxide-molecular dioxygen mixed gas under mild conditions.
- Mizuno, Kazuhiko,Tamai, Toshiyuki,Hashida, Isao,Otsuji, Yoshio,Inoue, Hiroo
-
p. 284 - 285
(2007/10/03)
-
- Nachweis und Reaktionen von photolytisch aus aromatischen Verbindungen and Tetranitromethan in 1,1,1,3,3,3-Hexafluor-2-propanol bei Raumtemperatur hergestellten Radikalkationen
-
Keywords: Hexafuorpropanol, Nitroverbindungen, Photochemie, Radikalkationen, Tetranitromethan
- Eberson, Lennart,Hartshorn, Michael P.,Persson, Ola
-
p. 2417 - 2418
(2007/10/03)
-
- Selective nitration versus oxidative dealkylation of hydroquinone ethers with nitrogen dioxide
-
Various alkyl-substituted p-dialkoxybenzenes (ArH) react readily with nitrogen dioxide (NO2) in dichloromethane solution via either nitration (ArNO2) or oxidative dealkylation to quinones (Q). Spectral transients indicate that these coupled processes proceed from the dialkoxybenzene radical cation (ArH+) formed as the common reactive intermediate from electron-transfer in the disproportionated precursor [ArH, NO+]NO3-. In fast subsequent steps, ArH+ undergoes homolytic coupling with NO2 (which leads to aromatic nitration) and nucleophilic attack of NO3- (which results in oxidative dealkylation). As such, the competition between nitration and oxidative dealkylation is effectively modulated by solvent polarity and added nitrate.
- Rathore,Bosch,Kochi
-
p. 6727 - 6758
(2007/10/02)
-
- Oxidative Dealkylation of Hydroquinone Ethers with Nitrogen Dioxide in the Convenient Preparation of Quinones
-
Various Hydroquinone dialkyl ethers (R2Q) are effectively converted by nitrogen dioxide into the corresponding quinone (Q) and alkyl nitrite (RONO) in dichloromethane at room temperature or below.The preparative procedure for the isolation of crystalline quinones in quantitative yield merely involves the convenient removal of the low boiling solvent in vacuo.Isotopic labelling studies demonstrate that the oxidative dealkylation proceeds via alkoxy scission of the labile cation radical (R2Q-cation radical) formed via the oxidation of the hydroquinone ether by nitrogen dioxide ( as the disproportionated ion pair NO+NO3-).The electron-transfer mechanism is confirmed by the spectral observation of R2Q-cation radical (identified by the isolation of the crystalline salt R2Q-cation radical-SbCl6-) and its rapid conversion into quinone and alkyl nitrite by combination with nitrate (NO3-) and nitric oxide (NO).
- Rathore, Rajendra,Bosch, Eric,Kochi, Jay K.
-
p. 1157 - 1166
(2007/10/02)
-
- Anodic Oxidation of Aryl Propargyl and Aryl Allyl Ethers at a Platinum Electrode
-
The oxidation reactions of aromatic 3,3-sigmatropic systems have been investigated under different conditions viz. (a) anodic oxidation in amphiprotic and aprotic media, (b) reaction with (diacetoxyiodo)benzene and (c) reaction promoted by ceric ammonium nitrate.
- Dhanalekshmii, Savithri,Balasubramanian, Kalpattu Kuppusamy,Venkatachalam, Chittoor Sivamakris.
-
p. 6387 - 6400
(2007/10/02)
-
- Kinetics and mechanisms of the gas-phase reactions of the NO3 radical with aromatic compounds
-
The kinetics and nitrated products of the gas-phase reactions of the NO3 radical with methoxybenzene, 1,2-, 1,3-, and 1,4-dimethoxybenzene, dibenzofuran and dibenzo-p-dioxin have been investigated at 297 ± 2 K and in the presence of one atmosphere of air. A relative rate method was used for the kinetic measurements. No reactions of methoxybenzene or dibenzofuran with the NO3 radical were observed. The dimethoxybenzenes were observed to react by H-atom abstraction and NO3 radical addition to the aromatic ring, while dibenzo-p-dioxin reacted by NO3 radical addition to the aromatic rings. For these compounds, the NO3 radical addition pathways were observed to be reversible. At the NO2 concentrations employed, the NO3-aromatic adducts reacted with NO2 and the observed rate constants increased with increasing NO2 concentration. However, for dibenzo-p-dioxin the observed rate constant became independent of the NO2 concentration for concentrations ≥ 4.8 × 1013 molecule cm-3, and under these conditions the rate constant of 6.8 × 10-14 cm3 molecule-1 s-1 was taken to be that for addition of the NO3 radical to the aromatic rings. The proposed NO3 radical reaction mechanisms are discussed.
- Kwok,Atkinson,Arey
-
p. 511 - 525
(2007/10/03)
-
- 13C NMR Spectra of Substituted o-Nitroanisoles and n-Butyl o-Nitrophenyl Ethers
-
13C NMR analyses of substituted o-nitroanisoles and n-butyl o-nitrophenyl ethers are reported. Key Words: 13C NMR - o-Nitroanisoles - n-Butyl o-nitrophenyl ethers
- Zeegers, Petrus J.,Thompson, Malcolm J.
-
p. 497 - 499
(2007/10/02)
-
- THE OXIDATION OF AROMATIC AMINES IN THE PRESENCE OF "ELECTRON-RICH" AROMATIC SYSTEMS
-
The oxidation of aromatic amines to the corresponding nitro substituents is performed under mild, nonacidic conditions in the presence of highly nucleophilic aromatic systems such as indoles and furans.
- Zabrowsky, Daniel L.,Moormann, Alan E.,Beck, Kenneth R.
-
p. 4501 - 4504
(2007/10/02)
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- NITRIC ACID ON SILICA GEL: A USEFUL NITRATING REAGENT FOR ACTIVATED AROMATIC COMPOUNDS
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Phenols and arylmethyl ethers are rapidly mononitrated by nitric acid adsorbed in silica gel at room temperature in high yields.
- Tapia, Ricardo,Torres, Glenda,Valderrama, Jaime A.
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p. 681 - 688
(2007/10/02)
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- I. Photochemical nitration of methoxybenzenes from charge-transfer complexes with tetranitromethane
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The direct irradiation of the charge-transfer (CT) absorption band of the 1/1 electron donor-acceptor complexes of dimethoxybenzenes with tetranitromethane leads to aromatic nitration with a high quantum yield.The analogous methoxytoluenes under the same photochemical conditions are converted in equally high yields to products of aromatic trinitromethylation.This dichotomy with different methoxybenzenes (ArH) is discussed within the context of the common reactive intermediates derived from the CT excitation of the complex.The subsequent interactions of the geminate fragments, i.e., +., C(NO2)3-, .NO2>, by radical-pair and ion-pair annihilation represent a unifying mechanism for the CT photochemistry leading to aromatic nitration and trinitromethylation.
- Sankararaman, S.,Kochi, J. K.
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p. 278 - 285
(2007/10/02)
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- Certain benzodiimidazoles and their use as radiation sensitizers
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This invention relates to novel benzodiimidazole diols and diones and their ability to sensitize hypoxic cells to radiation, thus demonstrating utility for enhancing the treatment of solid tumors by radiation in a subject in need of such treatment.
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- STUDIES ON QUINONES. XIV. OXIDATIVE DEMETHYLATION OF HYDROQUINONES DIMETHYLETHERS WITH NITRIC ACID- IMPREGNATED MANGANESE DIOXIDE
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The oxidative cleavage of several hydroquinones dimethylethers with nitric acid-impregnated manganese dioxide, in methylene chloride solution at room temperature, gave the corresponding quinones in 76-95percent yield.
- Errazuriz, B.,Tapia, R.,Valderrama, J. A.
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p. 819 - 822
(2007/10/02)
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- Electrochemical Nitration : Coupling between simultaneously electrogenerated aromatic radical cation and nitrogen dioxide
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Anodic nitration of 1,4-dimethoxybenzene has been performed in cationic, anionic and non ionic aqueous micellar systems in the presence of NaNO2.The results are best explained by a coupling between the simultaneously electrogenerated aromatic radical cation and nitrogen dioxide.
- Laurent, Eliane,Rauniyar, Govind,Thomalla, Marc
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