Nitro anion radical

The negative ClogP term shows that highly hydrophilic molecules for this data set would present better inhibitory activities against topo I. Two compounds (Ri = R3 = R4 = R5 = H, R2 = NO2 and Ri = R3 = R4 = R5 = H, R2 = F) in Table 4 for the development of QSAR Eq. 6 were deemed to be outliers on the basis of their deviation (>2s). The outlier (Ri = R3 = R4 = R5 = H, R2 = NO2) is much more active than expected, by three times the standard deviation. This may be due to the formation of nitro anion radicals that interact with DNA [48]. The other derivative (Ri = R3 = R4 = R5 = H, R2 = F) is... 

Nifurtimox (Lampit) is a nitrofuran derivative whose likely mechanism of action for kUhng of trypanosomes is through the production of activated forms of oxygen. Nifurtimox is reduced to the nitro anion radical, which reacts with oxygen to produce superoxide and hydrogen peroxide. The free radical metabolites, an absence of parasite catalase, and a peroxide dehciency lead to hpid peroxidation and cell damage. This production of activated oxygen results in toxicity to the protozoal cells. 

Fig. 6 Scheme of futile cycling of metronidazole in the presence of oxygen. Nitro anion radicals are converted back to the inactive reoxidized form. By-products of this conversion are superoxide radicals... 

As shown by means of electrochemical ESR spectroscopic methods and confirmed by ab initio calculations (Alberti et al. 1995), the first electron is accommodated in the more accessible nitrobenzopyran moiety. Next, the second electron fits into the nitroindoline moiety in virtually the same orbital that in the anion radical of mon<9-nitro-spiro(indoline-benzopyran), is occupied by the unpaired electron. The mono-nitro anion radical is also formed by the aforementioned reaction with terf-BuOK in DMSO, Scheme 1-63. 

The definition also includes species in which a common radical function such as a ketyl, nitro anion-radical, or semiquinone is conjugated with a heteroaromatic system, e.g., 6-9. Certain major radical series are, however,... 

The ion-pairs of nitropyridines continue to attract attention. Consistent with the substituent s being the primary residence for spin and charge in nitro anion-radicals, it was found that the counterion is associated with the oxygen atoms of the nitro group and lies on the C2 axis of the radical.80... 

The initially formed chlorides PyX ionize to a pyridinium halide while PyR represents mixed 1,4- and 1,2-dihydropyridines.233,234 4-Nitrobenzyl halides react by a different mechanism the initial step here is electron transfer from 66 to the halide to give a nitro anion-radical which subsequently loses halide. Since this reaction involves ionic intermediates it is much more susceptible to solvent effects than the atom transfer reaction.235,236... 

In reaction of aliphatic nitro compounds with alkyl radicals 6 7 generated from ethers or alcohols aminyloxides 69b could be detected79. Moreover dialkylaminyl-oxides 74b are formed, 67 being trapped from the corresponding nitroso compound. Reduction of nitro compound to nitroso compound probably occurs by electron transfer from alkyl radical 67 to nitro compound, subsequent dissociation of the resulting complex 68b giving nitro anion radical which finally disproportionates. 

Some halogenated alkyl groups that can undergo reductive dehalogenation (Fig. 3, reaction 7) Nitroarenes that can be reduced to nitro anion-radicals, nitrosoarenes, nitroxides, and hydroxylamines (Fig. 7, reaction 4)... 

The trypanocidal action of nifurtimox derives from its ability to undergo activation by partial reduction to nitro radical anions. Transfer of electrons from the activated drug then forms superoxide radical anions and other reactive oxygen species. Reaction of free radicals results in lipid peroxidation and membrane injury, enzyme inactivation, and DNA damage. Benznidazole also requires a one-electron transfer that generates nitro anion radicals, leading to cellular damage that kills the parasites. 

The requirement of light for the activation of oxyfluorfen and nitrofen has been known for years. However, the involvement of photosynthetic electron transport was doubted ( 40). At the moment, our hypothesis claims p-nitrophenylethers to be reduced to a (nitro-anion ) radical which subsequently initiates peroxidation of (galactolipid) polyunsaturated fatty acids and other membrane components. Apparently, also respiratory reactions are able to activate oxyfluorfen, since o ir heterotrophically growing cultures exhibit a small bleaching in the dark (Table I). Possibly these... 

Both NADPH cytochrome P450 reductase (P450 reductase) and NAD(P)H-quinone oxidoreductase (NQO) are flavin adenine nucleotide-containing enzymes that catalyze the reduction of quinones and quinone-like structures. However, P450 reductase is a microsomal enzyme that catalyzes a one-electron reduction to yield semiquinone radieals that can redox cycle to produce superoxide anion radicals, whereas NQO is a cytosolic enzyme that catalyzes a two-electron reduction to yield hydroquinones (Matsunaga et al., 2006). P450 reductase also can catalyze the one-electron reduction of nitroaromatics to the nitro anion radical, which can redox cycle ... 

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