Tocher J H, Edwards D I
Chemotherapy Research Unit, North East London Polytechnic, UK.
Free Radic Res Commun. 1988;4(5):269-76. doi: 10.3109/10715768809066891.
The electrochemical properties of three nitroimidazoles, a nitropyrazole, a nitrofuran and three nitrobenzenoid compounds have been extensively investigated in a range of solvents. The reduction pathway for the nitro group is independent of the cyclic function to which it is attached, but is strongly influenced by the nature of the solvent. In aqueous media, generally, a single, irreversible 4-electron reduction occurs to give the hydroxylamine. In aprotic media (dimethylformamide, methylene chloride or dimethylsulphoxide), a reversible one-electron reduction takes place to form a stable nitro radical anion. At more negative values, a further 3-electron reduction occurs, irreversibly to give the hydroxylamine. In mixed aqueous-organic systems, intermediate behaviour is found, with the reversibility of the RNO2/RNO.-2 couple increasing with addition of organic medium. The control of the reduction pathway, by changing the electrolytic medium is discussed in relation to the biological activities of the drugs and identification of the short-lived reduction intermediate responsible for DNA damage.
已在一系列溶剂中广泛研究了三种硝基咪唑、一种硝基吡唑、一种硝基呋喃和三种硝基苯类化合物的电化学性质。硝基的还原途径与其所连接的环状官能团无关，但受溶剂性质的强烈影响。在水性介质中，通常发生单一的、不可逆的4电子还原反应生成羟胺。在非质子介质（二甲基甲酰胺、二氯甲烷或二甲基亚砜）中，发生可逆的单电子还原反应形成稳定的硝基自由基阴离子。在更负的电位下，会进一步发生不可逆的3电子还原反应生成羟胺。在水-有机混合体系中，发现了中间行为，随着有机介质的加入，RNO2/RNO.-2电对的可逆性增加。结合药物的生物活性以及对导致DNA损伤的短寿命还原中间体的鉴定，讨论了通过改变电解介质对还原途径的控制。
