- Tertiary Butyl Nitrite Triggered Nitration of Phenols: Solvent- and Structure-Dependent Kinetic Study
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Nitration of phenols with tertiary butyl nitrite (TBN) obeyed second-order kinetics with a first-order dependence on [TBN] and [phenol] under acid-free conditions. Reaction rates were significantly altered by a change in the dielectric constant and other physical properties of solvent. The rate of nitration increased with an increase in temperature (303-323 K) in different solvent media (acetonitrile, dichloroethane, CCl4, dimethyl formamide (DMF), and toluene). The rates of nitration (log k) could not fit into either Amis or Kirkwood plots [log k' vs. (1/D) or [(D - 1)/(2D + 1)], but the trends were better explained by the basic form of multivariate linear solvent energy relationships (MLSER) suggested by the Koppel and Palm approach on the one hand and the Kamlet and Taft approach on the other hand. These observations probably substantiate that cumulative contributions of basic solvent parameters (equilibrium as well as frictional solvent effects) and solvent-solute interactions for solvation of transition state during nitration of phenols. Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups. Accordingly, the reactivity of structurally different phenols was found to follow the following sequence: p-OH > p-MeO > p-Me > H > m-Me > p-Cl > p-Br > m-Cl > p-NO2 > m-OH. The results are interpreted by Hammett's theory of linear free energy relationship. The reaction constant (Hammett's ρ) is a measure of the sensitivity of the reaction toward the electronic effects of the substituent. The rho (ρ) values obtained from the present experiments are fairly large negative values (ρ CH3) versus σ? or, Es or combined Taft's relationship. However, Charton's MLRA of the log k with polar, resonance, steric, hydrophobicity, and molar refractivity showing a very good linear relationship was obtained. It is of interest to note that when log kexp values are correlated with log kcal a perfect linearity is obtained with a correlation coefficient of unity, indicating the consonance between experimental and calculated rate constants in the present work.
- Kumar, M. Satish,Rajanna,Venkateswarlu,Rao, K. Lakshman
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supporting information
p. 171 - 196
(2016/04/09)
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- Ultrasonic and microwave-assisted synthesis of β-nitro styrenes and nitro phenols with tertiary butyl nitrite under acid-free conditions
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Tertiary butyl nitrite (TBN) is an acid-free and safe nitrating agent that provides preferentially β-nitrostyrenes with cinnamic acids and corresponding nitro derivatives with phenols in good yields under classical conditions. However, ultrasonic and microwave-assisted reactions reduced the reaction times substantially and enhanced the yields from good to excellent. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Kumar, M. Satish,Rajanna,Reddy, K. Rajendar,Venkateswarlu,Venkanna
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supporting information
p. 2672 - 2677
(2013/07/26)
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- Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate
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Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.
- Ganguly, Nemai C.,Dutta, Sanjoy,Datta, Mrityunjoy,De, Prithwiraj
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p. 733 - 735
(2007/10/03)
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- Nitrophenol derivatives oxidized by cerium(IV) ammonium nitrate (CAN) and their cytotoxicity
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Oxidation of a series of phenols with cerium(IV) ammonium nitrate (CAN) in acetonitrile undermild conditions yields the mixture of corresponding nitrophenols. In the cases of methylphenols and hydroxy-carboxylic acids, the steric effect may reduce the nitration reaction. Compounds 3 a and 4b showed selective activities to Hep 3B and Hep G2 cancer cell lines, respectively. Compound 2c showed selective activities to Hep G2 and MDA-MB-231 cancer cell lines. Further more, com pound 10b showed selective activities to Hep G2, Hep 3B, MCF-7 and MDA-MB-231 cancer cell lines.
- Pan, Wen-Bin,Wei, Li-Mei,Wei, Li-Lan,Wu, Chin-Chung,Chang, Fang-Rong,Wu, Yang-Chang
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p. 581 - 588
(2007/10/03)
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- On the role of nitrogen monoxide (nitric oxide) in the nitration of a tyrosine derivative and model compounds
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The nitration of tyrosine derivatives with nitrogen monoxide (nitric oxide) occurs only in the presence of dioxygen, and the hypothesized mechanism involves nitrogen dioxide (.NO2). For better understanding of the reaction mechanism, the nitration of model compounds - such as 1- and 2-naphthols and their corresponding 2- and 1-nitroso derivatives with nitrogen monoxide in the presence and in the absence of dioxygen was studied. The results described here show that tyrosine and naphthols do not undergo nitrosation when they react with .NO, and so nitrosation of tyrosine in biological systems is highly unlikely. In addition, the oxidation of nitrosonaphthols ? isonitrosonaphthols by nitric oxide and its derivatives to the corresponding nitro derivatives does not involve the oxoammonium ion, as reported previously. The mechanistic proposals are supported mainly by ESR investigation and electrochemical data. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Giorgini, Elisabetta,Petrucci, Rita,Astolfi, Paola,Mason, Ronald P.,Greci, Lucedio
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p. 4011 - 4017
(2007/10/03)
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- Hydroxylation of nitrated naphthalenes with KO2/crown ether
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Superoxide radical anion (O2/·-), generated by KO2/crown ether, is effective for hydroxylation of nitronaphthalenes. When mono- and di-nitronaphthalenes are treated with KO2/crown ether, hydroxylation results at
- Fukuhara,Hara,Nakanishi,Miyata
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p. 1532 - 1535
(2007/10/03)
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- Convenient Synthesis of Some Isomeric Dinitrohydroxynaphthalenes
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A convenient one-pot synthesis of 4,6-dinitro-1-hydroxy-; 2,4-dinitro-1-hydroxy-; 1-nitro-2-hydroxy-; 4,5-dinitro-2-hydroxy-; 5,8-dinitro-2-hydroxy-; and 4,8-dinitro-2-hydroxynaphthalenes has been achieved by the action of cerium(IV)ammonium nitrate on 1- and 2-hydroxynaphthalenes.Nuclear acetoxylation observed in the case of anisole under identical conditions is completely absent in hydroxynaphthalene series.
- Chawla, H. Mohindra,Mittal, Ram S.
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p. 751 - 752
(2007/10/02)
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- Catalytic reduction of nitro aromatic compounds with hydrogen sulfide and carbon monoxide
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In the reduction of di- or polynitro aromatic compounds by gaseous H2 S over a solid catalyst, addition of CO gas promotes formation of amino groups from all nitro groups in the molecule. A preferred embodiment is reduction of 2,4- and/or 2,6-dinitrotoluene in vapor phase at 325° C. over a supported iron or supported cobalt catalyst on a support comprising alumina. The amino products are useful for production of polyurethane resins.
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- REACTIONS OF AROMATIC POLYNITRO COMPOUNDS. LI. ? COMPLEXES OF POLYNITRONAPHTHALENES WITH SODIUM SULFITE
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The addition of sodium sulfite to polynitro derivatives of naphthalene was studied, and the structure of the obtained products was established by spectral methods as multiply charged anionic ? complexes.The products from the addition of one and two molecules of sodium sulfite to 1,3,6,8-tetranitronaphthalene were obtained in the free form for the first time.During the formation of the dicomplex SO3(2-) dianions add to one of the rings of 1,3,6,8-tetranitronaphthalene.In the monocomplexes and dicomplexes of 1,3,6,8-tetranitronaphthalene with sodium sulfite the charge of the anion is delocalized preferentially in the cyclohexadienyl ring of the ? complexes.
- Kaminskaya, E. G.,Gitis, S. S.
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p. 1287 - 1292
(2007/10/02)
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- Reactions in Micelles of Cetyltrimethylammonium Hydroxyde. Test of the Pseudophase Model for Kinetics
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The rate constants for reactions of OH- with 2,4-dinitrochlorobenzene (DCNB), 2,4-dinitrochloronaphthalene (DNCN), and p-nitrophenyl diphenyl phosphate (pNPDPP) in micellized cetyltrimethylammonium hydroxyde (CTAOH) do not conform to the pseudophase ion-exchanged model.The rate constants do not become constant when substrates are fully micellar bound and increase on addition of NaOH.However, with the more hydrophobic substrates DNCN and pNPDPP we appear to reach limiting rate constants at high or high .These observations can be explained on the assumption that the charge on a CTAOH micelle decreases on addition of OH-, i.e., the concentration of OH- in the micelle increases with increasing -> in the aqueous pseudophase.The rate-surfactant profiles for reactions of DNCN and pNPDPP can be interpreted quantitatively in these terms.For reactions of DNCB the rate data can be interpreted if we assume that added OH- also increasees binding of DNCB to the micelle.
- Bunton, Clifford A.,Gan, Leong-Huat,Moffatt, John R.,Romsted, Laurence S.,Savelli, Gianfranco
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p. 4118 - 4125
(2007/10/02)
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- Preparation of nitrophenols
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A process for the preparation of nitrophenols by adding over a period of time a suspension containing from about 4 to about 20 per cent weight/volume of nitrosated phenol to a nitric acid solution containing between 45 and 100 per cent by weight of nitric acid, said solution being maintained at a temperature in the range from about 45° to 100°C.
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