Neighboring Amide Participation in Thioether Oxidation: Relevance to Biological Oxidation
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- 作者：Richard S. Glass ; Gordon L. Hug ; Christian Schneich ; George S. Wilson ; Larisa Kuznetsova ; Tang-man Lee ; Malika Ammam ; Edward Lorance ; Thomas Nauser ; Gary S. Nichol ; Takuhei Yamamoto
- 刊名：Journal of the American Chemical Society
- 出版年：2009
- 出版时间：September 30, 2009
- 年：2009
- 卷：131
- 期：38
- 页码：13791-13805
- 全文大小：647K
- 年卷期：v.131,no.38(September 30, 2009)
- ISSN：1520-5126
文摘
To investigate neighboring amide participation in thioether oxidation, which may be relevant to brain oxidative stress accompanying β-amyloid peptide aggregation, conformationally constrained methylthionorbornyl derivatives with amido moieties were synthesized and characterized, including an X-ray crystallographic study of one of them. Electrochemical oxidation of these compounds, studied by cyclic voltammetry, revealed that their oxidation peak potentials were less positive for those compounds in which neighboring group participation was geometrically possible. Pulse radiolysis studies provided evidence for bond formation between the amide moiety and sulfur on one-electron oxidation in cases where the moieties are juxtaposed. Furthermore, molecular constraints in spiro analogues revealed that S−O bonds are formed on one-electron oxidation. DFT calculations suggest that isomeric σ*SO radicals are formed in these systems.