ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Absolute Configuration of Loroxanthin (=(3R, 3′R, 6′R)-β, ∊-Carotene-3, 19, 3′-triol)‘Loroxanthin’, isolated from Chlorella vulgaris, was separated by HPLC. methods in two major isomers, a mono-cis-loroxanthin and the all-trans-form. Solutions of the pure isomers easily set up again a mixture of the cis/trans-isomers. Extensive 1H-NMR. spectral measurements at 400 MHz allowed to establish the 3′, 6′-trans-configuration at the ∊-end group in both isomers and the (9E)-configuration in the mono-cis-isomer. The absolute configurations at C(3) and C(6′) were deduced from CD. correlations with synthetic (9Z, 3R, 6′R)-β, ∊-carotene-3, 19-diol (5) and (9E, 3R, 6′R)-β, ∊-carotene-3, 19-diol (6), respectively. Thus, all-trans-loroxanthin (3) is (9Z, 3R, 3′R, 6′R)-β, ∊-carotene-3, 19, 3′-triol and its predominant mono-cis-isomer is (9E, 3R, 3′R, 6′R)-β, ∊-carotene-3, 19, 3′-triol (4). Cooccurrence in the same organism and identical chirality at all centers suggest that loroxanthin is biosynthesized from lutein (2).
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19830660419
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