Effective 2,6-substitution of piperidine nitroxyl radical by carbonyl compound
Effective 2,6-substitution of piperidine nitroxyl radical by carbonyl compound
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DOI：
10.1016/j.tet.2010.02.004
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发表时间：
2010-03-27
期刊：
影响因子：
2.1
通讯作者：
Utsumi, Hideo
中科院分区：
文献类型：
--
作者：
Sakai, Kiyoshi;Yamada, Ken-ichi;Utsumi, Hideo
具有不成对电子的硝基自由基被广泛用作抗氧化剂、造影剂和自旋探针。虽然哌啶的硝基自由基有很多应用，但这些主要是四甲基哌啶类化合物，只有少数报道考虑N-O环的取代作为反应位点，如2,2,6,6-四取代哌啶硝基自由基。结果表明，在温和的反应条件下，2,2,6,6-四甲基哌啶-4- 1化合物的2,6位被环己基取代，生成2,2,6,6-四甲基哌啶-4- 1衍生物。用（15）N标记的NH(4)Cl代替（14）NH(4)Cl得到了一个有趣的结果：它得到了（15）N标记的2,2,6,6-四取代胡椒苷-4- 1-氧基，具有高（15）N含量。综上所述，新方法在温和条件下容易合成2,2,6,6-四取代胡椒苷- 1。(C) 2009年Elsevier Ltd.出版
Nitroxyl radicals (nitroxides) with unpaired electron are widely used as antioxidants, contrast agents, and spin probes. Although piperidine nitroxyl radicals have many applications, these are mainly tetramethylpiperidine compounds, and only a few reports consider the substitution of N-O surround as a reaction site, such as 2,2,6,6-tetrasubstituted piperidine nitroxyl radicals. Our results revealed that the 2,6-position of the 2,2,6,6-tetramethylpiperidin-4-one compound was substituted by cyclohexyl groups to produce 2,2,6,6-tetrasubstituted piperidin-4-one derivatives under mild reaction conditions. An interesting result was obtained by using (15)N-labeled NH(4)Cl instead of (14)NH(4)Cl: it gave (15)N-labeled 2,2,6,6-tetrasubstituted piperidin-4-one-1-oxyls with a high (15)N content. In conclusion, the new method for the synthesis of nitroxyl radicals readily yields 2,2,6,6-tetrasubstituted piperidin-l-one under mild conditions. (C) 2009 Published by Elsevier Ltd.