Nitration ozone-mediated

Ozone-Mediated Nitration of Aromatic Compounds with Lower Oxides of Nitrogen," Mori, T. Srnm Synlett, 1995, 383... 

Nitrogen dioxide in the presence of ozone has been used for aromatic nitrations." Such conditions are useful for the nitration of reactive and acid sensitive substrates. Lewis acids have been used in ozone-mediated nitrations with nitrogen dioxide." ... 

The ozone-mediated reaction of bicumene and some derivatives (11) with nitrogen dioxide in dichloromethane (kyodai nitration) at low temperatures results in the cleavage of the central C—C bond to yield the benzyl nitrate and products therefrom, in... 

Suzuki, H. and Mori, T. Ozone-mediated nitration of chlorobenzene and bromo-benzene and some methyl derivatives with nitrogen dioxide - High ort/io-Directing trends of the chlorine and bromine substituents, J. Chem. Soc., Perkin Trans. 2, 479-484, 1994. 

Mori T. and Suzuki, H. Ozone-mediated nitration of aromatic compounds with lower oxides of nitrogen (the Kyodai nitration). Synlett, 1995, 383-392. 

Ozone-mediated nitration (Kyodai nitration) of imidazole under neutral condition gave poor yields of 4-nitroimi-dazole. However, the yield improved dramatically with the addition of methanesulfonic acid. The combination NO2-O3 is a much more reactive electrophilic reagent since a reaction temperature of 0°C was sufficient (Scheme 56), <1996JCM244>. The 4-nitro product 238 could also be converted into 1,4-dinitroimidazole 239 over a long period. 

In spite of the increasing interest in nitroimidazoles as pharmaceuticals and in cancer therapy there has been little new material on nitration techniques. Perhaps the ozone-mediated nitration regime reported for alkylbenzenes might merit study as the reaction conditions are essentially neutral <93JCS(Pl)l59l>. Approaches through metallated species also offer promise (see below). 

Ozone-mediated nitration by the Kyodai nitration is snccessfully applied for various aromatic compounds [18,25-33]. The reaction proceeds by a double mode depending on the oxidation potential of the substrate. Deactivated aromatic compounds are likely to react with in most cases via the nitronium ion forming in (Equation 5.55), but substrates of lower oxidation potential are easily oxidised by NO3 to form the corresponding radical cations ... 

The ozone mediated reaction of aromatic acetals and acylal with nitrogen dioxide is suggested as a novel methodology for the nuclear nitration of acid sensitive aromatic compounds under neutral conditions [101],... 

Reactions in the troposphere are mediated by reactions involving hydroxyl radicals produced photochemically during daylight, by nitrate radicals that are significant during the night (Platt et al. 1984), by ozone and, in some circumstances by 0( P). 

The process of dissimilatory dentrification occurs anaerobically and is mediated by bacteria that use nitrate in place of oxygen as an acceptor of electrons during respiration. The result is the formation of molecular nitrogen and nitrous oxide. The nitrous oxide plays a role in the chemistry of stratospheric ozone and is, therefore, extremely important bio-geochemically. These bacteria are heterotrophic and derive energy from the anaerobic oxidation of organic compounds. 

Nitration. Mediated by ozone, the ately activated to deactivated arenes. E can be preserved. ... 

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