Das Carotinoidspektrum der Hagebutten von Rosa pomifera: Nachweis von (5Z)‐Neurosporin; Synthese von (3R, 15Z)‐Rubixanthin

Carotenoids from Hips of Rosa pomifera: Discovery of (5Z)‐Neurosporene; Synthesis of (3R, 15Z)‐Rubixanthin Extensive chromatographic separations of the mixture of carotenoids from ripe hips of R. pomifera have led to the identification of 43 individual compounds, namely (Scheme 2): (15 Z)‐phytoene (1), (15 Z)‐phytofluene (2), all‐(E)‐phytofluene (2a), ξ‐carotene (3), two mono‐(Z)‐ξ‐carotenes (3a and 3b), (6 R)‐ϵ, ψ‐carotene (4), a mono‐(Z)‐ϵ, ψ‐carotene (4a), β, ψ‐carotene (5), a mono‐(Z)‐β, ψ‐carotene (5a), neurosporene (6), (5 Z)‐neurosporene (6a), a mono‐(Z)‐neurosporene (6b), lycopene (7), five (Z)‐lycopenes (7a–7e), β, β‐carotene (8), two mono‐(Z)‐β, β‐carotenes (probably (9 Z)‐β, β‐carotene (8a) and (13 Z)‐β, β‐carotene (8b)), β‐cryptoxanthin (9), three (Z)‐β‐cryptoxanthins (9a–9c), rubixanthin (10), (5′ Z)‐rubixanthin (=gazaniaxanthin; 10a), (9′ Z)‐rubixanthin (10b), (13′ Z)‐ and (13 Z)‐rubixanthin (10c and 10d, resp.), (5′ Z, 13′ Z)‐ or (5′ Z, 13 Z)‐rubixanthin (10e), lutein (11), zeaxanthin (12), (13 Z)‐zeaxanthin (12b), a mono‐(Z)‐zeaxanthin (probably (9 Z)‐zeaxanthin (12a)), (8 R)‐mutatoxanthin (13), (8 S)‐mutatoxanthin (14), neoxanthin (15), (8′ R)‐neochrome (16), (8′ S)‐neochrome (17), a tetrahydroxycarotenoid (18?), a tetrahydroxy‐epoxy‐carotenoid (19?), and a trihydroxycarotenoid of unknown structure. Rubixanthin (10) and (5′ Z)‐rubixanthin (10a) can easily be distinguished by HPLC. separation and CD. spectra at low temperature. The synthesis of (3 R, 15 Z)‐rubixanthin (29) is described. The isolation of (5 Z)‐neurosporene (6a) supports the hypothesis that the ϵ‐end group arises by enzymatic cyclization of precursors having a (5 Z)‐ or (5′ Z)‐configuration.