Development of novel nitroxyl radicals for controlling reactivity with ascorbic acid
Development of novel nitroxyl radicals for controlling reactivity with ascorbic acid
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DOI：
10.1080/10715760902914575
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发表时间：
2009-01-01
影响因子：
3.3
通讯作者：
Utsumi, Hideo
中科院分区：
文献类型：
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作者：
Kinoshita, Yuichi;Yamada, Ken-Ichi;Utsumi, Hideo
氮氧自由基（nitroxide）含有未成对电子，被广泛认为是抗氧化剂、造影剂、自旋探针、辐射保护剂和聚合介质。硝酰基自由基可以与自由基和还原剂反应，其反应性取决于硝酰基自由基本身的基本结构。然而，还原剂容易还原这些自由基，并且它们失去其顺磁性和功能。因此，本研究的目的是开发各种功能性硝酰基自由基，特别是通过改进一系列2，6-取代硝酰基自由基的合成路线来关注对阿萨的稳定性。四乙基取代的哌啶硝酰基自由基8对阿萨的还原反应具有抗性，而2，6-二螺-4 '4“-二吡喃哌啶-4-酮-N-氧自由基5的二级反应速率常数比羟基-TEMPO和氧代-TEMPO的二级反应速率常数大10倍。该2，6-取代化合物对阿萨具有多种反应性，并有可能用作新的抗氧化剂、造影剂和自由基聚合剂。
Piperidine and pyrrolidine nitroxyl radicals (nitroxide) contain unpaired electrons and have been widely recognized as antioxidants, contrast agents, spin probes, radiation protective agents and polymerization mediators. Nitroxyl radicals can react with free radicals and reductants and their reactivities depend on the basic structure of the nitroxyl radicals themselves. However, reductants easily reduce these radicals and they lose their paramagnetic nature and function. Therefore, the aim of this study was to develop various functional nitroxyl radicals, particularly focusing on stability towards AsA through the improvement of the synthetic route for a series of 2,6-substituted nitroxyl radicals. Tetraethyl-substituted piperidine nitroxyl radical 8 exhibited resistance to AsA reduction and 2,6-dispiro-4'4 ''-dipyrane-piperidin-4-one-N-oxyl 5 had a second-order rate constant 10-times greater than those of hydroxyl-TEMPO and oxo-TEMPO. The 2,6-substituted compound offers various reactivities towards AsA and the possibility to be used as a new antioxidant, contrast agent and radical polymerizer.