- Nitration of deactivated aromatic compounds via mechanochemical reaction
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A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.
- Wu, Jian-Wei,Zhang, Pu,Guo, Zhi-Xin
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supporting information
(2021/05/05)
-
- Mass production method of phenylenediamine from high purity dinitrobenzene
-
The present invention relates to a method for producing phenylenediamine using the high purity of dinitrobenzene, which may manufacture meta-phenylenediamine having a high yield since dinitrobenzene can be produced without aniline as a byproduct. Meta-phenylenediamine is manufactured based on a cost effective raw material by using a process as above without a separate purification process, thereby drastically reducing a manufacturing cost compared to an existing process. Therefore, stable reaction can be induced in a synthetic process, thereby easily and safely manufacturing meta-phenylenediamine.COPYRIGHT KIPO 2020
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Paragraph 0028-0032; 0035-0038
(2020/04/09)
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- Transition-State Interactions in a Promiscuous Enzyme: Sulfate and Phosphate Monoester Hydrolysis by Pseudomonas aeruginosa Arylsulfatase
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Pseudomonas aeruginosa arylsulfatase (PAS) hydrolyzes sulfate and, promiscuously, phosphate monoesters. Enzyme-catalyzed sulfate transfer is crucial to a wide variety of biological processes, but detailed studies of the mechanistic contributions to its catalysis are lacking. We present linear free energy relationships (LFERs) and kinetic isotope effects (KIEs) of PAS and analyses of active site mutants that suggest a key role for leaving group (LG) stabilization. In LFERs PASWT has a much less negative Br?nsted coefficient (βleaving groupobs-Enz = 0.33) than the uncatalyzed reaction (βleaving groupobs = 1.81). This situation is diminished when cationic active site groups are exchanged for alanine. The considerable degree of bond breaking during the transition state (TS) is evidenced by an 18Obridge KIE of 1.0088. LFER and KIE data for several active site mutants point to leaving group stabilization by active site K375, in cooperation with H211. 15N KIEs and the increased sensitivity to leaving group ability of the sulfatase activity in neat D2O (βleaving groupH-D = +0.06) suggest that the mechanism for S-Obridge bond fission shifts, with decreasing leaving group ability, from charge compensation via Lewis acid interactions toward direct proton donation. 18Ononbridge KIEs indicate that the TS for PAS-catalyzed sulfate monoester hydrolysis has a significantly more associative character compared to the uncatalyzed reaction, while PAS-catalyzed phosphate monoester hydrolysis does not show this shift. This difference in enzyme-catalyzed TSs appears to be the major factor favoring specificity toward sulfate over phosphate esters by this promiscuous hydrolase, since other features are either too similar (uncatalyzed TS) or inherently favor phosphate (charge).
- Van Loo, Bert,Berry, Ryan,Boonyuen, Usa,Mohamed, Mark F.,Golicnik, Marko,Hengge, AlVan C.,Hollfelder, Florian
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p. 1363 - 1378
(2019/03/11)
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- PROCESS FOR THE MANUFACTURE OF (PER) FLUOROPOLYETHERS WITH AROMATIC END GROUPS
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The invention relates to a process which comprises the reaction of a (per)fluoropolyether peroxide with an optionally substituted aromatic or heteroaromatic compound. The process allows to obtain (per)fluoropolyether compounds having two chain ends, wherein one or both chain ends is a —CF2— group covalently bound to an optionally substituted aromatic or heteroaromatic group through a -carbon-carbon- bond. The invention further relates to the use of these compounds and to their derivatives as additives for perfluorinated oils and greases.
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- Competition between electron-donor and electron-acceptor substituents in nitrotoluene isomers: A photoelectron spectroscopy and ab initio investigation
-
We present an investigation of the close relationship between chemical structure, physical properties and reactivity of the three nitrotoluene isomers: a joint experimental and theoretical study, based on X-ray photoelectron spectroscopy (XPS) measurements and ab initio calculations, addressing the complex interplay between the competing electron-donor and electron-acceptor effects of the nitro- and methyl-substituents on the chemical properties of the nitrotoluene isomers. As the main results of the investigation we: (i) point out that accurate ab initio calculations play a key role in the complete assignment of photoemission measurements, as well as in the estimate of proton affinities in the case of all the eligible sites; (ii) revisit, at a more quantitative level, textbook models based on inductive and resonant effects of different substituents of the aromatic ring, as well as on the hyper-conjugative connection of the methyl group to the π-conjugated system; (iii) provide an accurate analysis of correlation patterns between calculated proton affinities and core-ionization energies, which represent a powerful tool, capable of predicting site-specific reactivities of polysubstituted molecules in the case of electrophilic aromatic substitution reactions.
- Rondino, Flaminia,Catone, Daniele,Mattioli, Giuseppe,Bonapasta, Aldo Amore,Bolognesi, Paola,Casavola, Anna Rita,Coreno, Marcello,O'Keeffe, Patrick,Avaldi, Lorenzo
-
p. 5272 - 5282
(2014/01/23)
-
- Click chemistry inspired facile synthesis and bioevaluation of novel triazolyl analogs of Ludartin
-
A convenient and modular synthesis involving diastereoselective Michael addition followed by regioselective Huisgen 1,3-dipolar cycloaddition reaction was carried out to furnish 1,4-disubstituted-1,2,3-triazoles of Ludartin. This reaction scheme involving Michael addition followed by regioselective Huisgen 1,3-dipolar cycloaddition reaction leading to the formation of triazolyl analogs is being reported for the first time. All the triazolyl products were characterised using spectral data analysis. Sulphorhodamine B cytotoxicity screening of the resulting products against a panel of five human cancerous cell-lines revealed that few of the analogs display promising broad spectrum cytotoxic effect. Among all the synthesized compounds, only 3q displayed the best cytotoxic effect with IC50 values of 12, 11, 38, 39 and 8.5 μM but less than the standard Ludartin (1) with IC50 values of 6.3, 7.4, 7.5, 6.9 and 0.5 μM against human neuroblastoma (T98G), lung (A-549), prostate (PC-3), colon (HCT-116) and breast (MCF-7) cancer cell lines, respectively. The present synthesis was designed based on the previous literature reports of Ludartin as an aromatase inhibitor. Our work provides an initial study on structure-activity relationship of triazolyl analogs of sesquiterpene lactones in general and Ludartin (1) in particular.
- Lone, Shabir H.,Bhat, Khursheed A.,Majeed, Rabiya,Hamid, Abid,Khuroo, Mohd A.
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p. 1047 - 1051
(2014/03/21)
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- Preparation of heteropoly acid based amphiphilic salts supported by nano oxides and their catalytic performance in the nitration of aromatics
-
A series of Keggin heteropoly acid anion based amphiphilic salts supported by nano oxides were synthesized and used as catalysts in the nitration of aromatic compounds with HNO3. The reaction conditions in the nitration of toluene were optimized and both 92.6% conversion and good para selectivity (ortho:para = 1.09) were obtained.
- Wang, Peng-Cheng,Yao, Kai,Lu, Ming
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p. 2197 - 2202
(2013/03/14)
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- Preparation, catalytic performance and theoretical study of porous sulfated binary metal oxides shell (SO42 -/M1xO y-M2xOy) using pollen grain templates
-
Porous micro-sized particles of binary metal oxide (SO4 2 -/M1xOy-M2xOy) shell were prepared by template-directed synthesis method employing HCl-treated pollen grains. With 150 m2/g high surface area, these solid acids could provide more acid sites and thus obtain better catalytic activity. Using aromatic nitration as the typical reaction, their catalytic performances were evaluated and showed a significant improvement in both conversion and regioselectivity. Then, with chlorobenzene as substrate, theoretical studies were performed to investigate the interaction between transition metals and chlorobenzene. The results showed that the excellent para-selectivity was closely relative to the metal ion in these solid acids.
- Wang, Peng Cheng,Yao, Kai,Zhu, Jie,Liu, Xiang,Lu, Ting Ting,Lu, Ming
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-
- Regioselectivity nitration of aromatics with N2O5 in PEG-based dicationic ionic liquid
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Regioselective mononitration of simple aromatic compounds has been investigated with N2O5 as nitrating agent and a new PEG200-based dicationic acidic ionic liquid (PEG200-DAIL) as catalyst. The results of experiments show that this nitration system can significantly improve the para-selectivity of alkyl-benzenes and the ortho-selectivity of halogenated-benzenes. The PEG200-DAIL exhibits recyclable temperature-dependant phase behavior in CCl4 solvent, and it can be recycled without apparent loss of catalytic activity, and only 5% loss of weight is observed after six times recycling.
- Wang, Peng-Cheng,Lu, Ming
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supporting information; experimental part
p. 1452 - 1455
(2011/05/16)
-
- Ethylammonium nitrate (EAN)/Tf2O and EAN/TFAA: Ionic liquid based systems for aromatic nitration
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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.
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experimental part
p. 8088 - 8094
(2011/11/13)
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- Regioselective nitration of deactivated mono-substituted benzenes using acyl nitrates over reusable acidic zeolite catalysts
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Nitration of benzonitrile was investigated using a nitric acid/acid anhydride/zeolite catalyst system under different reaction conditions. Trifluoroacetic and chloroacetic anhydrides were found to be the most active among the anhydrides tried. Also, zeolites Hβ and Fe3+β (Si/ Al = 12.5) were found to be the most active catalysts. For example, nitration of benzonitrile with trifluoroacetyl nitrate under reflux conditions in dichloromethane gave 3- and 4-nitrobenzonitriles in quantitative yield, of which the para-isomer represented 24-28%. The yield of para-isomer was improved to 33% when passivated Hβ was used under similar reaction conditions. This is easily the most para-selective nitration of benzonitrile ever recorded. Also, no ortho-isomer was formed under the conditions tried. The zeolite can be easily recovered, regenerated by heating and reused up to six times to give results similar to those obtained with a fresh sample of the catalyst. The nitration system was applied successfully to a range of deactivated mono-substituted benzenes to give para-isomers in significantly higher proportions than in the corresponding traditional nitration reactions.
- Smith, Keith,Ajarim, Mansour D.,El-Hiti, Gamal A.
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experimental part
p. 270 - 278
(2010/12/19)
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- Synthesis, properties and in vitro photodynamic activity of water-soluble azaphthalocyanines and azanaphthalocyanines
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In this work zinc azaphthalocyanines (AzaPcs) from the group of tetrapyrazinoporphyrazines and zinc azanaphthalocyanines from the group of tetra[6,7]quinoxalinoporphyrazines (TQP) with eight diethylaminoethylsulfanyl substituents were synthesized. Tertiary amines were later quaternized with ethyl iodide to obtain water-soluble photosensitizers (PSs). Quaternized compounds showed high singlet oxygen quantum yields as determined in DMF by monitoring decomposition of 1,3-diphenylisobenzofuran. In water medium, quaternized AzaPc derivatives appeared in monomeric form in a wide range of concentrations while quaternized TQP derivatives showed aggregation at higher concentrations (over 1 μm). Photodynamic activity was tested on Hep2 cells using light of λ > 640 nm. Both quaternized dyes showed high photodynamic activity (IC 50 = 104 and 220 nm for AzaPc and TQP, respectively). Dark toxicity was not detected even at the highest concentration used in in vitro tests (200 μm) which indicates a promising therapeutic index of these new substances. Tested compounds localized inside the cells mainly within the lysosomes thus suggesting an endocytic mechanism of cellular uptake. No localization within mitochondria was detected. A great advantage of TQP derivatives over other PSs is their very strong absorption at 747 nm that allows activation at wavelengths penetrating deeper into human tissues.
- Zimcik, Petr,Miletin, Miroslav,Radilova, Hana,Novakova, Veronika,Kopecky, Kamil,Svec, Jaroslav,Rudolf, Emil
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scheme or table
p. 168 - 175
(2010/04/04)
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- Aromatic nitration using nitroguanidine and EGDN
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Acid catalyzed nitration has been examined using a variety of novel nitration agents: guanidine nitrate (GN) and nitroguanidine (NQ) as well as the simple nitrate ester, ethylene glycol dinitrate (EGDN). Reactions with either activated or deactivated aromatic substrates proceed rapidly and in high yield. Regioselectivity was similar for all nitrating agents examined. The synthetic advantages of liquid EGDN include high solubility in organic solvents, strong nitration activity and ease of preparation.
- Oxley, Jimmie C.,Smith, James L.,Moran, Jesse S.,Canino, Jonathan N.,Almog, Joseph
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p. 4449 - 4451
(2008/12/21)
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- Urea nitrate and nitrourea: powerful and regioselective aromatic nitration agents
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Urea nitrate (UN) and nitrourea (NU), easily prepared from urea and nitric acid, convert deactivated aromatic compounds to the corresponding nitrated derivatives with a high yield and a high regioselectivity under very mild conditions. The performance of the two reagents is quite similar indicating that NU is an intermediate in the UN nitration process.
- Almog, Joseph,Klein, Asne,Sokol, Anat,Sasson, Yoel,Sonenfeld, Dana,Tamiri, Tsippy
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p. 8651 - 8652
(2007/10/03)
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- A convenient method for the oxidation of aromatic amines to nitro compounds using tetra-n-alkylammonium bromates
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Tetra-n-propyl and tetra-n-butylammonium bromates were used for the oxidation of a variety of aromatic amines to nitro compounds. Reaction condition and recovery simple and yield of products high.
- Das, Satya Sandhya,Nath, Utpal,Deb, Dibakar,Das, Pranab J.
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p. 2359 - 2363
(2007/10/03)
-
- Faujasite catalysis of aromatic nitrations with dinitrogen pentoxide. The effect of aluminium content on catalytic activity and regioselectivity: The nitration of pyrazole
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The reaction of 1-chloro-2-nitrobenzene with dinitrogen pentoxide in dichloromethane catalysed by H-faujasite zeolites F-712, F-720, F-780 and F-901, giving 1-chloro-2,4-dinitro- and 1-chloro-2,6-dinitrobenzene in approximately 30:1 ratio, is a kinetically first-order process. First-order rate constants are independent of the concentration of N2O5 and proportional to the mass of catalyst used. Specific rate constants, obtained by dividing the first-order rate constant by the mass of faujasite, are constant for a given faujasite. Amongst the faujasites, they increase in approximate proportion to the aluminium content. A mechanism is proposed in which the protons in the faujasite, near aluminium in the faujasite framework, are replaced by nitronium ions derived from N2O5 in a fast pre-equilibrium process. This produces active sites for transfer of nitronium ion from faujasite to aromatic in the rate-determining step. The similar reactions of 2-nitrotoluene, too fast for kinetic study, reveal that the ratio of 2,4- to 2,6-dinitrotoluene in the product increases with the aluminium content of the faujasite. Nitration of nitrobenzene is also catalysed by faujasite. Relative reactivities of nitrobenzene, 1-chloro-2-nitro- and 1-chloro-4-nitrobenzene are compared to those found in mixed-acid nitration. Pyrazole can be nitrated readily with N2O5 over faujasites, yielding 1,4-dinitropyrazole in 80% yield under mild conditions.
- Claridge, Robert P.,Lancaster, N. Llewellyn,Millar, Ross W.,Moodie, Roy B.,Sandall, John P.B.
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p. 197 - 200
(2007/10/03)
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- Texaphyrin conjugates and uses thereof
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Texaphyrin/chemotherapeutic drug conjugates, optionally including a platinum(II) or platinum(IV) metal chelating site and/or complex, are useful for treating atheroma, tumors and other neoplastic tissue, neovascular-related diseases, as well as other conditions that are typically responsive to chemotherapy, radiation sensitization and photodynamic therapy.
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- A novel method for the nitration of deactivated aromatic compounds
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Novel nitration systems comprising nitric acid, trifluoroacetic anhydride and zeolite Hβ, with or without acetic anhydride, are described. The system having no acetic anhydride is more active and readily nitrates deactivated substrates such as nitrobenzene, benzonitrile, benzoic acid or 4-nitrotoluene to give predominantly the product substituted meta to the deactivating group. The system incorporating acetic anhydride is more moderate in activity, and nitrates moderately deactivated systems such as halogenobenzenes quantitatively within two hours at ice-salt bath temperature, and provides very high selectivity for the para-nitrated product. This system also nitrates 2-nitrotoluene to give high selectivity for 2,4-dinitrotoluene production. Furthermore, the system can be used for direct double nitration of toluene and gives a 92% yield of 2,4-dinitrotoluene with a 2,4- : 2,6-dinitrotoluene ratio of 25:1. Even greater selectivity (96% yield and 70:1 selectivity) can be achieved in the latter reaction by conducting the reaction in one flask but in two stages, with trifluoroacetic anhydride added only in the second stage. The Royal Society of Chemistry 2000.
- Smith, Keith,Gibbins, Tracy,Millar, Ross W.,Claridge, Robert P.
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p. 2753 - 2758
(2007/10/03)
-
- Energy transfer, electron transfer, and addition reactions of triplet state of 1,3-dihydroimidazole-2-thiones investigated by laser flash photolysis
-
The transient absorption bands observed at ca. 400 and 550 nm for 1,3- dihydro-2H-imidazole-2-thione (IT), 1,3-dihydro-1-methyl-2H-imidazole-2- thione (MIT), and 1,3-dihydro-2H-benzimidazole-2-thione (BIT) have been assigned to their triplet states (3IT* 's) by the quenching and sensitizing experiments using laser flash photolysis technique. Short intrinsic triplet lifetimes and relatively high triplet energies have been evaluated as characteristics of 3IT* 's. For electron acceptors, photoinduced electron- transfer reaction occurs via 3IT* 's in the diffusion controlled limit. The nucleophilic character of 3IT* 's was confirmed by changing the substituents of alkenes on the addition reactions. MO calculations indicate that the lowest electronic configurations of both 3IT* and 3MIT* have 3(n,π*) character, while 3BIT* has 3(π,π*) character. The addition reactivity of 3BIT* is slightly higher than those of 3IT* and 3MIT*, which is opposite to the general tendency.
- Alam, Maksudul M.,Ito, Osamu
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p. 339 - 345
(2007/10/03)
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- Zirconium-catalysed Oxidation of Primary Aromatic Amines to Nitro Compounds Using tert-Butylhydroperoxide
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A broad range of primary aromatic amines (1a-x) with electron donating and accepting substituents are oxidized in good to excellent yields to the nitro compounds 3a-x using tert-butylhydroperoxide as the oxidant and Zr(OtBu)4 as the catalyst. The corresponding nitroso compounds 2m,-2n, 2s and 2u can be isolated in the conversion of electron-rich anilines 1m, 1n, 1s and 1u. The aminopyridines 5a-d are also converted to the corresponding nitropyridines 6a-d, but in lower yields (41-47%).
- Krohn, Karsten,Kuepke, Jochen,Rieger, Hagen
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p. 335 - 339
(2007/10/03)
-
- Aprotic diazotization in the presence of cuprous cyanide
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In a procedure of extreme simplicity and rapidity a mixture of an aromatic primary amine, copper (I) cyanide and an alkyl nitrite in dimethyl sulphoxide yielded fair to moderate yields of the corresponding nitriles. Side processes observed were reduction (NH2&[H), nitration (NH2←NO2) and hydroxylation (NH2&[OH). In the case of polyhaloanilines halogen dance products could be detected.
- Giumanini, Angelo G.,Verardo, Giancarlo,Geatti, Paola,Strazzolini, Paolo
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p. 7137 - 7148
(2007/10/03)
-
- 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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- Unusual Isomer Distribution of Dinitrobenzenes and Nitrophenols Formed as Side Products during the Ozone-mediated Nitration of Benzene with Nitrogen Dioxide. Further Evidence for the Alternative Mechanism of Electrophilic Nitration of Arenes
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Dinitrobenzenes and nitrophenols formed as side products in the title reaction leading to nitrobenzene show an isomer distribution that is significantly different from those observed in the conventional nitration using nitric acid or nitric acid-sulfuric acid, suggesting the operation of a non-classical nitration mechanism involving nitrogen trioxide as the initial electrophile.
- Suzuki, Hitomi,Mori, Tadashi
-
-
- 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)
-
- Charge Transfer Complexes of Pyrene with Dinitro- and Trinitrobenzene Acceptors
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The charge transfer (CT) compexes formed between pyrene with some Dinitrobenzenes (DNB) and 1,3,5-Trinitrobenzene (TNB) acceptors are studied in solution and solid state using UV-visible, infrared and fluorescence spectroscopies.The equilibrium constants (Kc) for these complexes in solution have been calculated.The values of Kc follow the order o-DNB > m-DNB p-DNB TNB.This order is explained by considering the role that steric effects may play in the CT complex formation.In addition, the fluorescence quenching of pyrene with different acceptors is investigated.The effect of medium viscosity and temperature on the efficiency of quenching is also studied.Finally, the electrical properties for the solid CT complexes are measured. - Keywords: Pyrene CT complexes / Equilibrium constants / Fluorescence quenching / Electrical conductivity
- Ayad, Mohamad M.
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p. 123 - 134
(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)
-
- Non-pollutional process for producing aromatic nitro compounds without using a mineral acid
-
The present invention relates to a process for producing an aromatic nitro compound by introducing a nitrogen oxide gas and ozone-containing oxygen or air into a halogenated organic solvent dissolving or suspending therein an aromatic compound, thereby subjecting the aromatic compound to nitration. By the use of a system comprising the nitrogen oxide and ozone-containing oxygen or air as the nitrating agent, the aromatic nitro compound can be produced under mild conditions without using any mineral acid. In addition, the various disadvantages due to the use of mineral acid in the conventional process can be avoided by the process of the present invention.
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-
- Ozone-mediated Nitration of Alkylbenzenes and Related Compounds with Nitrogen Dioxide
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In the presence of ozone, nitrogen dioxide exhibits a strong nitrating ability for alkylbenzenes at low temperatures, converting them into the corresponding nitro derivatives in high yield.The addition of a protonic acid as catalyst enhances considerably the ability of this nitrating system and leads to a good yield of polynitro compounds.The reaction is clean and proceeds rapidly without any accompanying side-chain substitution or aryl-aryl coupling.It shows no kinetic dependence on the concentration of substrates and, as far as can be judged from relative reactivities and isomer distributions of products, it gives the appearance of being an electrophilic aromatic process.A possible role for nitrogen trioxide has been suggested as the initial electrophilic agent for the nitration of alkylbenzenes.
- Suzuki, Hitomi,Murashima, Takashi,Kozai, Iku,Mori, Tadashi
-
p. 1591 - 1598
(2007/10/02)
-
- HETEROGENEOUS ELECTRON TRANSFER RATE CONSTANTS FOR THE SECOND REDUCTION PROCESS OF SOME DINITROAROMATICS
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Standard heterogeneous electron transfer rate constants k0 for the second reduction process of 1,2-, 1,3-, and 1,4-dinitrobenzenes were evaluated by the Gileadi method.The temperature dependences of k0 were investigated using Marcus' and other expression for ΔG*.However, it was found that to explain the values of k0 and its variation with temperature, it might be prudent to take into consideration the dielectric constant near the site of the reactant (the anion radical) and the product (the dianion).
- Mohammad, Mahbood,Khan, Athar Yaseen,Qureshi, Romana,Ashraf, Naila,Begum, Waheeda
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p. 1410 - 1418
(2007/10/02)
-
- Oxidizing Aromatic Amines to Nitroarenes with the HOF-MeCN System
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Fluorine reacts with wet acetonitrile to produce an oxidizing agent which oxidizes all types of aromatic amines to the corresponding nitroarenes, also offering a way to make 18O containing nitro derivatives.
- Kol, Moshe,Rozen, Shlomo
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p. 567 - 568
(2007/10/02)
-
- A Non-acid Methodology for Polynitration of Arenes at Low Temperatures
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In the presence of ozone and an appropriate catalyst, nitrogen dioxide acts as a powerful nitrating agent at low temperatures, converting arenes into polynitro derivatives in good yields.
- Suzuki, Hitomi,Murashima, Takashi,Shimizu, Kazuhiro,Tsukamoto, Kenkichi
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p. 1049 - 1050
(2007/10/02)
-
- Electrophilic Aromatic Substitution. Part 37. Products of Aromatic Nitrations of some Chloronitrobenzenes and Substituted Benzoic Acids in Solutions of Dinitrogen Pentaoxide and of Nitronium Salts in Nitric Acid
-
Yields of aromatic products of nitration in nitric acid solutions containing dinitrogen pentaoxide or nitronium salt have been determined.Evidence for the intrusion of a mechanism other than the normal nitronium ion one comes from comparison of products in the two media and from the observation of 15N NMR CIDPN effects.The additional mechanism operative with some substrates in concentrated solutions of dinitrogen pentaoxide is postulated to be one in which reversible addition of the NO3 radical is followed by combination with NO2.Dienes produced in this way can give aromatic nitroproducts by elimination of nitric acid.Nitrodecarboxylation of substituted benzoic acids occurs by a radical process.
- Moodie, Roy B.,Sanderson, Andrew J.,Willmer, Richard
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p. 645 - 650
(2007/10/02)
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- NITRATION OF AROMATIC COMPOUNDS CATALYZED BY ZrO2/SO42-
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Catalytic activity was demonstrated for zirconium dioxide, which is a solid acid, modified by sulfate ions in the nitration of inactive aromatic compounds.
- Nagi, Sh. M.,Zubkov, E. A.,Shubin, V. G.
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p. 1500 - 1502
(2007/10/02)
-
- Electrophilic Aromatic Substitution. Part 35. Chlorination of 1,3-Dinitrobenzene, 1-Chloro-2,4-dinitrobenzene, and 2,4-Dinitrotoluene with Nitric Acid and Hydrogen Chloride or Chlorine in Sulphuric Acid or Oleum
-
Solutions of sulphuric acid or oleum containing HCl or Cl2 and nitric acid have been found both to chlorinate and nitrate deactivated aromatic compounds.The kinetics and products of the chlorination of 1,3-dinitrobenzene and 1-chloro-2,4-dinitrobenzene in sulphuric acid or oleum containing HCl and nitric acid at 130 deg C, and the kinetics and products of the chlorination of 2,4-dinitrotoluene at 90 deg C in sulphuric acid or oleum containing Cl2 and nitric acid, are reported. 1,3-Dinitrobenzene and 1-chloro-2,4-dinitrobenzene were predominantly chlorinated. 2,4-Dinitrotoluene gave approximately equal amounts of 6-chloro-2,4-dinitrotoluene and 2,4,6-trinitrotoluene.The results show that under these conditions, chlorination and nitration are competing electrophilic reactions, and that chlorination is less selective than nitration.Possible mechanisms for chlorination are discussed.
- Melhuish, Martin W.,Moodie, Roy B.
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p. 667 - 674
(2007/10/02)
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- Oxidation of Primary Amines by Dimethyldioxirane
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Dimethyldioxirane oxidizes primary amines rapidly, and generally in high yield, to the corresponding nitro compounds.The method can also be used to syntesize polynitro compounds.
- Murray, Robert W.,Rajadhyaksha, Shirish N.,Mohan, Lily
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p. 5783 - 5788
(2007/10/02)
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- THE FIRST SUCCESSFUL DIRECT AZOCOUPLING OF NITROAROMATIC ANION-RADICAL
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o-Dinitrobenzene dianion reacts with p-N,N-dimethylaminobenzenediazonium cation, forming 2-nitro-4'-N,N-dimethylaminoazobenzene. o-Dinitrobenzene anion-radical, interacting with benzenediazonium cations that contain N,N'-dimethylamino or nitro group in para-position, yields 3-nitro-4-hydroxy-4'-N,N-dimethylaminoazobenzene and 3,4'-dinitro-4-hydroxyazobenzene, respectively.The above compounds are formed in media promoting the stability of ion pairs between o-dinitrobenzene dianions or anions-radicals and potassium cations.With the dissociation of ion pairs, only the electron-transfer reaction products are observed.
- Todres, Z. V.,Hovsepyan, G. TS.,Ionina, YE. A.
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p. 5199 - 5204
(2007/10/02)
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- FUNCTIONAL GROUP OXIDATION USING SODIUM PERBORATE
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Sodium perborate in acetic acid is an effective reagent for the oxidation of anilines to nitroarenes and of sulphides to either sulphoxides or sulphones.It is also an excellent reagent for the oxidative deprotection of ketone dimethylhydrazones.Baeyer-Villiger oxidation of ketones can be carried out with sodium perborate in either trifluoroacetic acid or acetic acid/trifluoroacetic acid mixtures, and hydroquinones and certain highly substituted phenols are smoothly converted into quinones.
- McKillop, Alexander,Tarbin, Jonathan A.
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p. 1753 - 1758
(2007/10/02)
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- Entropy Changes and Electron Affinities from Gas-Phase Electron-Transfer Equilibria: A(-) + B = A + B(-)
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By measuring the electron-transfer equilibria 1, A(-) + B = A + B(-), at 150 deg C with a pulsed electron high-pressure mass spectrometer we determined the ΔGo1 values involving 12 new compounds.Measurements of the temperature dependence of K1 for 21 reactions involving some of the new compounds and many compounds whose ΔGo1 had been determined previously led, via van't Hoff plots, to ΔHo1 and ΔSo1 values.These were interconnecting such that ΔHo and ΔSo continuous scales (ladders) were obtained.These were anchored to SO2 whose electron affinity is accurately known.Available geometries and vibrational frequencies for SO2 and SO2(-) permit the evaluation of So(SO2(-)) - So(SO2).Through the ΔSo scale the So(B(-)) - So(B) for the other compounds B could be obtained also.Certain regularities in the So(B(-)) - So(B) data permitted entropy estimates to be made also for compounds for which no van't Hoff plots were made.In this manner a table of ΔHo, ΔSo, and ΔGo data for the electron capture e + B = B(-) was obtained, which contains some 50 compounds B.Most of the compounds are substituted benzenes, quinones, conjugated acid anhydrides, and perfluorinated organics.
- Chowdhury, Swapan,Heinis, Thomas,Grimsrud, Eric P.,Kebarle, Paul
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p. 2747 - 2752
(2007/10/02)
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- Electron Affinities of Di- and Tetracyanoethylene and Cyanobenzenes Based on Measurements of Gas-Phase Electron-Transfer Equilibria
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The electron affinities of tetracyanoethylene, trans-1,2-dicyanoethylene, and eleven substituted benzonitriles as well as two naphthonitriles were determined by measurement of the electron-transfer equilibria A-+B=A+B- with a pulsed electron high ion source pressure mass spectrometer.Rate constants for exothermic electron transfer involving the cyano compounds were found to be near unit collision efficiency.The EA (tetracyanoethylene)=3.17 eV obtained in the present work is considerably higher than the 2.3 eV photodetachment value of Palmer and Lyons.The electron affinities of benzene and benzonitrile substituted by CN, CHO, and NO2 increase in the given order, while the order for nitrobenzene is CHO, CN, NO2.This reversal of order is explained on the basis of a larger attenuation of the ?-withdrawing effect relative to the field effect of substituents when the electron density in the ?* single-electron orbital is decreased.
- Chowdhury, Swapan,Kebarle, Paul
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p. 5453 - 5459
(2007/10/02)
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- DETERMINATION OF SOME AMINO COMPOUNDS WITH AMMONIUM METAVANADATE
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A quick and convenient method has been developed for the micro determination of some hydrazines and aromatic amines.The sample (1-10 mg) is allowed to react with 2 mL of 0.3 N ammonium metavanadate reagent and 10 mL of 10 N H2SO4.The unconsumed reagent can be accurately titrated with 0.025 N Fe(II) solution using N-phenylanthranilic acid as indicator.The error does not exceed +/- 1percent.
- Ahmad, Saeed,Shukla, Jamaluddin,Shukla, Ishwar Chandra
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p. 339 - 344
(2007/10/02)
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- SODIUM PERBORATE - A CHEAP AND EFFECTIVE REAGENT FOR THE OXIDATION OF ANILINES AND SULPHIDES
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Sodium perborate in acetic acid is an effective reagent for the oxidation of anilines to the corresponding nitroarenes; it is also highly effective for the oxidation of sulphides to either sulphoxides or sulphones.
- McKillop, Alexander,Tarbin, Jonathan A.
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p. 1505 - 1508
(2007/10/02)
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- Reduction of Aryldiazonium Salts to Arenes
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Aryldiazonium fluoroborates are smoothly reduced to the corresponding hydrocarbon derivatives by warming with DMF.When the amine has an electron donating substituent, the reaction proceeds at 65 deg C.When the amine has electron withdrawing substituents, the reaction proceeds rapidly at 25-45 deg C.Deamination of 2,4,6-trichlorobenzenediazonium fluoroborate with tetramethylurea gives acetaldehyde as an unexpected product together with 2,4,6-trichlorobenzene.The amines can also be deaminated with DMF without separation of the diazonium salt in aqueous or non-aqueous medium.
- Lahoti, R. J.,Parameswaran, V.,Wagle, D. R.
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p. 767 - 769
(2007/10/02)
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- AMBIPHILIC FUROXAN RING. BENZOFUROXAN OXIDATION BY PERACID AND REDUCTION BY COPPER
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Monopersulfuric acid, trifluoroperacetic acid and hydrogen peroxide in polyphosphonic acid, or with selenium dioxide in t-butyl alcohol, or in tetramethylene sulfone have each oxidized benzofuroxan into o-dinitrobenzene.Monopersulfuric acid oxidized 4-nitrobenzofuroxan into 1,2,3-trinitrobenzene (80percent) and 4,6-dinitrobenzofuroxan into 1,2,3,5-tetranitrobenzene (99percent); hydrogen peroxide in polyphosphoric acid was moderately efficient for the latter oxidation.Copper in acidified ethanol transformed 4,6-dinitrobenzofuroxan into picramide quantitatively.
- Boyer, Joseph H.,Huang, Chrongbao
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p. 1233 - 1240
(2007/10/02)
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- Solvent Effects in the Nitration of Nitrobenzene
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Results obtained from nitration of nitrobenzene and methyl phenyl sulfone with nitronium hexafluorophosphate in nitromethane gave a good Hammett relationship using ?+ as the substituent constant (ρ=-8.5,n=11,r=0.99), in contrast to the results
- Fujiwara, Kenji,Andoh, Takayuki,Arai, Mitsuru,Tamura, Masamitsu,Yoshida, Tadao
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p. 4973 - 4976
(2007/10/02)
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- Selective weed control with m-dinitrobenzene
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Weeds can be controlled by the application as a herbicide of m-dinitrobenzene. This compound is particularly effective for selectively controlling weeds in agronomic crops.
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