SNH Approach in the Synthesis of Nitronyl Nitroxides

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• 作者：Oleg N. Chupakhin ; Irina A. Utepova ; Mikhail V. Varaksin ; Evgeny V. Tretyakov ; Galina V. Romanenko ; Dmitry V. Stass ; Victor I. Ovcharenko
• 刊名：Journal of Organic Chemistry
• 出版年：2009
• 出版时间：April 3, 2009
• 年：2009
• 卷：74
• 期：7
• 页码：2870-2872
• 全文大小：138K
• 年卷期：v.74,no.7(April 3, 2009)
• ISSN：1520-6904

文摘

We show that the S_N^H approach opens up new possibilities in the synthesis of hetaryl-substituted nitronyl nitroxides. The reaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl lithium salt with pyridine-, pyrimidine-, pyrazine-, isoquinoline-, phthalazine-, quinoxaline-, and 1,2,4-triazine-N-oxides readily gives rise to the corresponding paramagnetic hetarenes. The reaction of this salt with quinoxaline-1,4-dioxide enabled the synthesis of the first nitronyl nitroxide biradical with two spin-labeled fragments in the vicinal positions of the heteroaromatic cycle; the persistent biradicals of this type were not known earlier. The characterizations of all persistent radicals obtained by S_N^H synthetic strategy include X-ray crystal structures, EPR investigation, and static magnetic susceptibility measurements.