- Carotenoids with two chromophores: Carotenoid retinoates
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In this study, carotenoid retinoates are described for the first time. The preparation was achieved by the azolide method. Various sec carotenols reacted with N-retinoylimidazol in the presence of catalytic amounts of sodium hydride. Mono- and diretinoates of (3R,3′R)-zeaxanthin and its (3S,3′S)- enantiomer, (9Z,9′Z; 3R,3′R)-alloxanthin, (3R,3′R)-7,8, 7′,8′-tetrahydro-3,3′-dihydroxy-β,β-carotene-8, 8′-dione and (3R,6R,3′R,6′R)-ε,ε-carotene-3, 3′-diol (lactucaxanthin), as well as monoretinoates of (3R,3′RS,6′R)-3′-methoxy-β,ε-caroten-3-ol, (3R,3′RS,6′R)-3-methoxy-β,ε-caroten-3′-ol, (2R,6′RS)-β,ε-caroten-2-ol, (3R,3′S; meso)-astaxanthin and (2′R)-aleuriaxanthin are reported in this study. Spectroscopic properties (1H-NMR mass spectrometry, visible and circular dichroism spectra) are discussed. Studies on other carotenoid derivatives with two chromophores are referred to here.
- Hertzberg, Sissel,Lutnaes, Bjart Frode,Liaaen-Jensen, Synnove
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experimental part
p. 511 - 525
(2011/05/12)
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- Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. V. Synthese von Astacin
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Starting from optically inactive astaxanthin intermediates, the highly oxygenated carotenoid astacene was synthesized in seven steps (55percent overall yield from 6-oxo-isophorone).Key features of the new approach are base- and acid-catalyzed rearrangements of acetylenic intermediates such as those described in Schemes 2, 7 and 8.
- Widmer, Erich,Lukac, Teodor,Bernhard, Kurt,Zell, Reinhard
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p. 671 - 683
(2007/10/02)
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- Animal carotenoids. 12. Chirality of asterinic acid.
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The chirality of monoacetylenic asterinic acid [(3S,3'S)-7,8-didehydroastaxanthin, 1a] has been established by NaBH4-reduction and hydrolysis of the corresponding diesters 1b and 1c providing the tetrol 9 and CD-correlation with diatoxanthin [3R,3'R)-7,8-didehydro-beta, beta-carotene-3,3'-diol, 10]. Diacetylenic asterinic acid [3S,3'S)-7,8,7',8'-tetradehydro-beta, beta-carotene-3,3'-diol, 2a] was assigned the some absolute configuration by similar conversion to the diacetylenic tetrol 11 and CD-correlation with alloxanthin [3R,3'R)-7,8,7',8'-tetradehydro-beta, beta-carotene-3,3'-diol, 12]. IR and CD properties of the diacetates 1C and 2C of the naturally occurring alpha-ketols are reported.
- Berger,Borch,Liaaen-Jensen
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p. 243 - 247
(2007/10/12)
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