Chemistry of C-2 Glyceryl Radicals: Indications for a New Mechanism of Lipid Damage

Autor:	Martin Senn, Stephan N. Müller, Oleg I. Shadyro, Rohit Batra, Micail Kisel, Bernd Giese
Rok vydání:	1997
Předmět:	Chemistry Radical General Chemistry Photochemistry Biochemistry Toluene Heterolysis Catalysis Solvent Elimination reaction chemistry.chemical_compound Colloid and Surface Chemistry Reaction rate constant Radical disproportionation Bond cleavage
Zdroj:	Journal of the American Chemical Society. 119:2795-2803
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja9641416
Popis:	Precursors for the selective generation of C-2 glyceryl radicals were synthesized, and the chemical behavior of the corresponding radicals was investigated by ESR spectroscopy, product analysis, and kinetic measurements. It was found that cleavage of the β-C,O bond proceeds rapidly, if a hydroxyl group is present at the radical carbon center. The rate constant for the elimination of a β-acetoxy group from radical 30 was dependent on the solvent (kE = 4 × 105 s-1 in methanol, kE = 2 × 107 s-1 in toluene). With these results and ab initio calculations a concerted elimination mechanism is suggested. α-Methoxy-substituted C-2 glyceryl radicals 42 and 43 showed heterolytic β-C,O bond cleavage under formation of radical cations. With ester-substituted radicals 24 and 35 no elimination could be observed. To demonstrate the biological significance of these findings, C-2 lysolecithin radical 53 was generated, which led to fast β-elimination.
Databáze:	OpenAIRE
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