Über die Carotinoide Flavoxanthin und Chrysanthemaxanthin: 1H-NMR.-, 13C-NMR.- und Massen-Spektren und absolute Konfiguration. (Kritische Überprüfung veröffentlichter chemischer und physikalischer Daten)
✍ Scribed by Herbert Cadosch; Ulrich Vögeli; Peter Rüedi; Conrad Hans Eugster
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- German
- Weight
- 643 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0018-019X
No coin nor oath required. For personal study only.
✦ Synopsis
On the Carotenoids Flavoxanthin and Chrysanthemaxanthin: ^1^H‐NMR., ^13^C‐NMR. and Mass Spectra, Absolute Configuration, Survey of Published Data
Very pure flavoxanthin (1) and chrysanthemaxanthin (2) have been reisolated from flower heads of Taraxacum officinale. Both compounds were characterized by chromatographic, chemical and chiroptical data and extensive NMR. measurements. Examination of many published data on 1 and 2 led to the conclusion that flavoxanthin has often been mistaken for chrysanthemaxanthin and vice versa.
Chemical degradation of 1 and 2 to (−)‐loliolide (5) coupled with NMR. evidence (ASIS, spin‐decoupling, NOE) allowed the assignment of the absolute configurations of 1 and 2. Thus (+)‐flavoxanthin is (3S,5R,8R, 3′R,6′R)‐5, 8‐epoxy‐5, 8‐dihydro‐β, ε‐carotene‐3, 3′‐diol and (+)‐chrysanthemaxanthin its C(8)‐epimer.