Spectroscopic studies on the reaction of superoxide ion with tocopherol model compound,...

The reaction of superoxide ion, O2-, with alpha-tocopherol model compound, 6-hydroxy-2,2,5,7,8-pentamethylchroman (1b), was investigated spectrophotometrically in acetonitirle. The transient absorption (lambda max = 330 nm) observed at the initial stage of the reaction was ascribed to the chromanoxyl-type radical, one-elecron oxidation product of compound 1b, on the basis of the spectroscopic [ultraviolet (UV)/visible and electron spin resonance (ESR)] data. Further, the final product observed was ascribable to the tocopherol quinone (3).