title: Neighboring amide participation in thioether oxidation: relevance to biological oxidation.
abstract: To investigate neighboring amide participation in thioether oxidation, which may be relevant to brain oxidative stress accompanying beta-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 sigma*(SO) radicals are formed in these systems.
authors.affiliation: Department of Chemistry, The University of Arizona, Tucson, Arizona 85721, USA. rglass@u.arizona.edu
authors.forename: Richard S
authors.initials: RS
authors.lastname: Glass
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Hug
authors.forename: Christian
authors.initials: C
authors.lastname: Schöneich
authors.forename: George S
authors.initials: GS
authors.lastname: Wilson
authors.forename: Larisa
authors.initials: L
authors.lastname: Kuznetsova
authors.forename: Tang-man
authors.initials: TM
authors.lastname: Lee
authors.forename: Malika
authors.initials: M
authors.lastname: Ammam
authors.forename: Edward
authors.initials: E
authors.lastname: Lorance
authors.forename: Thomas
authors.initials: T
authors.lastname: Nauser
authors.forename: Gary S
authors.initials: GS
authors.lastname: Nichol
authors.forename: Takuhei
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000577:Amides / Q000737:chemistry* / Q000378:metabolism; D000682:Amyloid / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D013440:Sulfides / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000577:Amides; D000682:Amyloid; D013440:Sulfides