Trennung und absolute Konfiguration der C(8)‐epimeren (all‐E)‐Neochrome (Trollichrome) und ‐Dinochrome

Separation and Absolute Configuration of the C(8)‐Epimeric (app‐E)‐Neochromes (Trollichromes) and ‐Dinochromes The C(8′)‐epimers of (all‐E)‐neochrome were separated by HPLC and carefully characterized. The faster eluted isomer, m.p. 197.8–198.3°, is shown to have structure 3 ((3S,5R,6R,3′S,5′R,8′R)‐5′,8′‐epoxy‐6,7‐dodehydro‐5,6,5′,8′‐tetrahydro‐β,β‐carotene‐3,5,3′‐triol). To the other isomer, m.p. 195‐195.5°, we assign structure 6, ((3S,5R,6R,3′S,5′R,8′R)‐5′,8′‐epoxy‐6,7‐didehydro‐5,6,5′,8′‐tetrahydro‐β,β‐carotene‐3,5,3′‐triol). The already known epimeric dinochromes (= 3‐O‐acetylneochromes) can now be formulated as 4 and 5, (‘epimer 1’ and its trimethylsilyl ether) and 7 and 8, (‘epimer 2’ and its trimethylsilyl ether), respectively.