- Establishment of heterolytic and homolytic Y-NO2 bond dissociation energy scales of nitro-containing compounds in acetonitrile: Chemical origin of NO2 release and capture
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(Chemical Equation Presented) The first heterolytic and homolytic N(O)-NO2 bond dissociation energy scales of three types Y-nitro (Y = N, O) compounds and corresponding radical anions in acetonitrile were established by using titration calorimetry combined with relevant electrochemical data through proper thermodynamic cycles.
- Li, Xin,Zhu, Xiao-Qing,Zhang, Fan,Wang, Xiao-Xiao,Cheng, Jin-Pei
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p. 2428 - 2431
(2008/09/20)
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- Oxidation of benzylic alcohols and ethers to carbonyl derivatives by nitric acid in dichloromethane
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Nitric acid in dichloromethane may be successfully employed for the oxidation of benzylic alcohols and ethers to the corresponding carbonyl compounds. The proposed method proved to be of general applicability, affording very good yields of aldehydes and ketones and showing interesting chemoselectivity in many instances, allowing competitive aromatic nitration to be avoided, as well as - in the case of aldehydes - any further oxidation to carboxylic acids. The reaction probably proceeds by a radical mechanism, the active species in the oxidation process being NO2. Competitive formation of nitro esters was observed in some cases, whereas poor results were obtained with allylic and non-benzylic substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Strazzolini, Paolo,Runcio, Antonio
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p. 526 - 536
(2007/10/03)
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- NO donors, part 8 [1]: Synthesis and vasodilating activities of substituted benzylnitrates compared to cyclohexylmethylnitrate and GTN
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A series of substituted benzylnitrates (1) and the formally but not chemically similar cyclohexylmethylnitrate (CHMN) have been synthesised. Vasodilating activities were measured on endothelium-intact and NG-nitro-L-arginine (L-NNA)-blocked porcine right coronary arteries, precontracted with prostaglandin F2α (PGF2α). Glyceroltrinitrate (GTN) was used as reference. In intact coronary arteries the vasodilating activities of all benzylnitrates are lower compared with GTN, but higher compared with CHMN. However, blocking the function of the endothelium by L-NNA, the activity of all benzylnitrates increased, whereas that of CHMN and GTN remained nearly unaffected. Under these conditions, the mononitrates 4-nitro-benzylnitrate (1c) and 4-nitrooxymethyl-benzonitrile (1h) even showed higher vasodilator activities than the trinitrate GTN and in general, vasorelaxation by the benzylnitrates as defined by the concentrations for half maximal effects (EC50 values) was found to be 2-3 orders of magnitude higher than that induced by CHMN. The study demonstrates that the in vitro activities of organic nitrates do not correlate with the number of nitrate groups within the molecule nor to the lipophilicity of the molecules. Instead, vasodilator activity is highly sensitive to the structure and the type of the substituents in the molecular carrier of the nitrate group.
- Wessler, Christoph,Homann, Alexander,Fricke, Uwe,Lehmann, Jochen
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p. 581 - 586
(2007/10/03)
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- Oxidation of Aromatic Compounds. I. Oxidation of Methyl Derivatives of Nitrobenzene and Aniline in the System HSO3F-PbO2
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Low-temperature oxidation of methyl derivatives of nitrobenzene and aniline in the system HSO3F-PbO2 proceeds with intermediate formation of radical cations and results in replacement of hydrogen in one or two methyl groups or yields compounds of the diphenylmethane and biphenyl series.
- Rudenko, A. P.,Korovina, N. S.,Aver'yanov, S. F.
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p. 1077 - 1083
(2007/10/03)
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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
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p. 1591 - 1598
(2007/10/02)
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- Mercury-assisted solvolyses of alkyl halides. Simple procedures for the preparation of nitrate esters, acetate esters, alcohols and ethers
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The reactions of a wide variety of alkyl halides with mercury(I) and/or (II) nitrate in 1,2-dimethoxyethane, mercury(II) acetate in acetic acid, aqueous mercury(II) perchlorate, and mercury(II) perchlorate in alcohol solvents have been investigated; as a result, simple high yield procedures for the conversion of alkyl halides into the corresponding nitrate esters, acetate esters, alcohols and ethers have been developed.
- McKillop,Ford
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p. 2467 - 2475
(2007/10/05)
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