In this study we report on the preparation of 3-oxolutein (1) by MnO2- and NiO2-oxidation of lutein (2) and the complete structure elucidation of this carotenoid by spectroscopic (UV/VIS, IR, 1H-NMR, 13C-NMR, CD, MS) methods and chemical reaction (NaBH4 reduction). The complete assignment of the 13CNMR spectrum of this carotenoid will be presented for the first time. A new carotenoid with alternative structure (8) is the major product of NiO2-oxidation of lutein (2) and partial spectroscopic characterization supports a structural assignment in which the β-end group has undergone extensive oxidation with concomitant ring opening.
Keywords: Carotenoids, oxidation of lutein, 3'-oxolutein, stereochemistry, spectroscopic characterization, structure elucidation
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