The two novel ketocarotenoids (I) and (II) are isolated from Daphnia magna.

Two minor xanthophylls of the marine alga Eutreptiella gymnastica were assigned the structures (3S,5R,6S,3′R,6′R)-3′-hydroxy-3,6-epoxy-5,6-dihydro-β,ε-caroten-4-one (α-cryptoeutreptiellanone) and (3S,5R,6S,3′R)-3′-hydroxy-3,6-epoxy-7′,8′-didehydro-5,6-dihydro-β,β-caroten-4-one (β-cryptoeutreptiellanone) from spectroscopic and chemical evidence. Tentative chiralities are based on CD, 1H NMR and biogenetic correlations. (3S,5R,6R,3′R)-Diadinoxanthin, (3R,3′R)-diatoxanthin and (3S,5R,6R,3′S,5′R,6′S)-neoxanthin had CD and 1H NMR properties consistent with the chiralities assigned from other sources. A trace pigment had spectroscopic properties compatible with its identification as taraxanthin (lutein epoxide). Chemosystematic and phylogenetic considerations are made.

The carotenoids of selected Cryptophyceae, Rhodomonas D3 and Cryptomonas ovata , have been examined by methods including HPLC, mass spectrometry 1 H NMR and circular dichroism. 3′R,6′R- Chirality has been assigned to monadoxanthin from 1 H NMR and CD data; β,ϵ-carotene possessed the common 6′R- chirality . The quantitative distribution pattern of carotenoids in Cryptophyceae established here and previously, totalling five species' is discussed in chemosystematic context. β,ϵ-Carotene (3–8% of total) is the major carotene, accompanied by ϵ,ϵ-carotene (0.2%), β,β-carotene (0–1%) and lycopene (0-trace). Zeaxanthin (2%) was identified in C. ovate . The diacetylenic alloxanthin is the major carotenoid (70–88%), and the monoacetylenic crocoxanthin (5–15%) and monadoxanthin (0–16%) less abundant. No epoxidic or allenic carotenoids could be detected. The biosynthetic precursor of acetylenic carotenoids in this primitive algal class is discussed. The significance of Cryptophyceae in the marine food chain is commented on, using alloxanthin as an indicator.

Die chiroptischen Eigenschaften der Titelverbindung (Ia) (aus Corynebacterium poinsettiae) und ihres Silylethers (Ib) werden untersucht.

Chemischer InformationsdienstVolume 15, Issue 40 Organic Dyes ChemInform Abstract: BACTERIAL CAROTENOIDS. 50. ON THE STRUCTURES OF (3S)-FLEXIXANTHIN AND (3S,2′S)-2′-HYDROXYFLEXIXANTHIN A. G. ANDREWES, A. G. ANDREWESSearch for more papers by this authorP. FOSS, P. FOSSSearch for more papers by this authorG. BORCH, G. BORCHSearch for more papers by this authorS. LIAAEN-JENSEN, S. LIAAEN-JENSENSearch for more papers by this author A. G. ANDREWES, A. G. ANDREWESSearch for more papers by this authorP. FOSS, P. FOSSSearch for more papers by this authorG. BORCH, G. BORCHSearch for more papers by this authorS. LIAAEN-JENSEN, S. LIAAEN-JENSENSearch for more papers by this author First published: October 2, 1984 https://doi.org/10.1002/chin.198440276Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue40October 2, 1984 RelatedInformation

The partly racemized nature of β,β-caroten-2-ol from the moth Cerura vinula and of β,β-caroten-2-ol, 2′-hydroxy-β,β-caroten-2-one and β,β-carotene-2,2′-diol from the stick insect Ectatosoma tiaratum was indicated by CD and confirmed by 1H-NMR of their MTPA esters in the presence of Eu(fod)3 shift reagent. Possible enzymic reactions causing the mixtures of the 2R- and 2S-enantiomers are discussed briefly.

The structural elucidation of the minor carotenoid sulfates from the marine sponge lanthella basta is discussed in context with the structure assigned to the major sulfate bastaxanthin (c; 3,19,17′-trihydroxy-7,8-didehydro-β-κ-carotene-3′,6′-dione 3-sulfate. Plausible structures are assigned to other bastaxanthins (b,b2, c2, d, e and f) on the basis of electroic, IR, 1H NMR, mass and CD spectra, electrophoretic behaviour, chemical derivatization and enzymatic or acid-catalysed hydrolysis. The minor sulfates represent structural variation in the cylopentane end group with different oxidation levels. Bastaxanthol b (desulfated bastaxanthin b) was a minor carotenoid constituent of l. basta. Including tentative chiralities, the structures favoured for the bastaxanthins are: c2, (3R,3′R, 5′R)-3,19,3′-trihydroxy-7,8-didehydro-β,κ-caroten-6′-one 3-sulfate; b2, (3R,3′R,5′R)-3, 19-dihydroxy-7,8-didehydro-β,κ- dione 3-sulfate; b, (3R,1′R, 5′R)-3, 19-dihydroxy 3′,6′-dioxo-7,8-didehydro-β,κ-caroten-17′-al 3-sulfate; d. (3R,1′R,3′R,5′R)-3, 19,3′,17′-tetrahydroxy 7,8 didehydro-β,κ-caroten-6′-one 3-sulfate; e. hydrogen (3R,1′R,5′R)-3, 19-dihydroxy-3′,6′-dioxo-7,8-didehydro-β,κ-caroten-17′-oate 3 sulfate (?); and f, hydrogen (3R.1′R,3′R,5′R)-3,19,3′-trihydroxy-7,8-didehydro-6′-oxo-β,κ-caroten-17′-oate 3-sulfate; for bastaxanthol b(3R.1′R.5′R)-3, 19-dihydroxy-3′,6′-dioxo-7,8-didehydro-β,κ-caroten-17′-al. The bastaxanthins are considered as metabolic products of l. basta, diadinoxanthin of phytoplankton origin representing a plausiable precursor.

1.1. The carotenoprotein alloporin ex Allopora californica contains optically pure (3S,3′S)-astaxanthin as prosthetic group, here confirmed by the camphanate method.2.2. Individual recombinations are reported for the colourless apoalloporin with the three isomers of astaxanthin (3S,3′S; 3R,3′S, meso and 3R,3′R), (3S)-adonirubin and (3R,3′R)-actinioerythrol to semisynthetic carotenoporteins. The carotenoprotein with (3S,3′S)-astaxanthin as prosthetic group exhibited the largest bathochromic shift.3.3. The Cotton effects of apoalloporin and of the semisynthetic carotenoproteins based on the three astaxanthin isomers, were very similar.4.4. Gel filtration data together with previous mol. wt determination suggest that alloporin is not a globular protein, consistent with a high content of helix-breaking amino acids.5.5. Apoalloporin appeared from 1H NMR, 13C NMR and CD data to have a quaternary structure similar to that of alloporin. However, gel filtration data revealed a lower equivalent Stokes radius.6.6. The quantitative amino acid composition of alloporin is reported. An exceptionally high content of acidic amino acids may explain the stable arrangement of alloporin in the CaCO3 skeleton of the coral.

1.1. The chirality of astaxanthin from the carotenoproteins of Homarus gammarus, crustacyanin (lobster shells) and ovoverdin (lobster eggs), has been examined by the camphanate method. Crustacyanin contained (3S,3′S)-axtaxanthin, (3R,3′S, meso)-astaxanthin and (3R,3′R)-astaxanthin in relative proportion 33:28:39. Astaxanthin ex ovoverdin consisted of the three optical isomers in ratio 30:28:42, closely similar to the ratio 31:25:44 found for total lobster egg astaxanthin.2.2. Individual recombination studies with apocrustacyanin and the natural astaxanthin mixture, the three pure, synthetic, optical isomers of astaxanthin and (3S)-adonirubin are reported. The recombined carotenoproteins were characterized by electronic and CD spectra and approximate mol. wt determined by ultrafiltration.3.3. The recombination method used resulted in carotenoproteins of α-crustacyanin size. The semisynthetic carotenoproteins obtained by recombination with each of the three astaxanthin isomers or (3S)-adonirubin showed only minor differences in their electronic and CD spectra relative to those of native α-crustacyanin. It is concluded that the chirality of the prosthetic group is not critical.4.4. No recombination between apo-ovoverdin and astaxanthin could be achieved. The CD properties for ovoverdin are discussed.

The identity of the carotenoids tedaniaxanthin and allopurpurin from marine sponges has been demonstrated by a direct quantitative comparison of their I2-catalysed stereomutation mixtures (HPLC and visible spectra). Studies on the geometrical isomerism are reported. The 2R-configuration is assigned on the basis of a CD-correlation of the HPLC-purified all-trans isomer and (3R,3′R)-aloxanthin.

Chemical and spectroscopic evidence including 1H NMR and CD is presented, demonstrating the (3R,6R,3′R,6′R)-ε,ε-carotene-3,3′-diol structure of a new carotenoid, lactucaxanthin. Lactucaxanthin, isolated from Lactuca sativa, is the sixth chiral isomer encountered in nature ofthe ten possible chiral isomers of ε,ε-carotene-3,3−diol. In achemosystematic screening,lactucaxanthin was restricted to Lactuca and a few closely related genera within the tribe Cichorieae of the Compositae.

1.1. The quantitative carotenoid composition of shells of the common northern circumpolar shrimp Pandalus borealis (Crustaceae Malacostraca, order Decapoda) (i) fresh frozen, (ii) boiled and (iii) processed shrimp meal, is reported. Astaxanthin, present as the free diol, mono-and diester with higher fatty acids, was identified by co-chromatography with authentic standards, conversion to astacene and spectral criteria (electronic-, mass- and CD spectra).2.2. By conversion to its diester with (−) camphanic acid astaxanthin from unboiled shells was shown by HPLC analysis to consist of the (3S, 3′S), (3R,3′R; meso) and (3R,3′R) isomers in ratio 25:52:23.3.3. Natural astaxanthin monoester was by similar procedure found to consist of the (3S)-ol and the (3R)-ol in ration 47:53, Saponification of the monoester in the absence of oxygen provided astaxanthin, shown by the above HPLC method to consist of the (3S,3′S), (3R,3′S;meso) and (3R,3′R) isomers in ration 17:50:33. Natural astaxanthin diester provided astaxanthin, containing the optical isomers (3S,3′S), (3R,3′S; meso) and (3R,3′R) in ratio 12:46:43.4.4. The strongly racemized nature of astaxanthin and its monoester was confirmed by the chiroptical data. The CD data for the natural astaxanthin diester confirmed a high degree of racemization with some preference for R-configuration (ca, 13% optical purity).5.5. The data suggest some preference for 3R-configuration of astaxanthin in the in vivo acylation reaction.

The quantitative carotenoid composition of natural blooms of Oscillatoria rubescens and O. agardhii is reported and compared with previous isolations. Chemical or enzymatic conversion of oscillaxanthin to the chiral aglycone failed. CD-correlation of oscillaxanthin hexaacetate with (2S,2′S)-bacterioruberin, (2′R)-plectaniaxanthin and (2′R)-plectaniaxanthin-2′-β-D-glucoside tetraacetate support the 2R,2′R-configuration for oscillaxanthin.

Details are reported for the configurational assignment of peridinin as 3S, 5R, 6R, 3′S, 5′R, 6′S including ozonolytic degradation of its p-bromobenzoate to derivatives of known chirality obtained from fucoxanthin and violaxanthin. Details regarding derivatization and CD correlations in favour of the same chirality for dinoxanthin = neoxanthin 3-acetate are given.