- METHODS FOR SYNTHESIS OF CHIRAL INTERMEDIATES OF CAROTENOIDS, CAROTENOID ANALOGS, AND CAROTENOID DERIVATIVES
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A method used for synthesizing intermediates for use in the synthesis of carotenoids and carotenoid analogs, and/or carotenoid derivatives. In some embodiments, the invention includes methods for synthesizing optically active intermediates useful for the synthesis of optically active carotenoids.
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Page/Page column 58
(2010/10/20)
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- Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. II. Ein neues Konzept fuer die Synthese von (3RS,3'RS)-Astaxanthin
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Starting from 6-oxo-isophorone (2) a new concept for a seven-step synthesis of (3RS,3'RS)-astaxanthin (1) has been developed.As a key feature of the new approach, the oxidation state of astaxanthin (1) is adjusted already at an early stage of the synthesis.Thus, manipulation on more complex intermediates later in the synthesis is reduced to a minimum.Acetonide 10 or dimer 13 represent the key intermediates of this concept (Scheme 2).The whole sequence has been run on a kg scale with an overall yield of 52percent (s.Scheme 5).
- Widmer, Erich,Zell, Reinhard,Broger, Emil Albin,Crameri, Yvo,Wagner, Hans Peter,et al.
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p. 2436 - 2446
(2007/10/02)
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- Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. III. Ein neues Konzept fuer die Synthese der enantiomeren Astaxanthine
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A new and efficient concept for the total synthesis of (3S,3'S)- and (3R,3'R)-astaxanthin (1a and 1c, resp.) in high overall yield and up to 99,2percent enantiomeric purity is described.Key intermediates are the (S)- and (R)-acetals 10 and 17, respectively (Scheme 2).These chiral building blocks were synthesized via three different routes: a) functionalization of enantiomeric 3-hydroxy-6-oxo-isophorons 2 and 11, respectively (Scheme 2); b) optical resolution of 3,4-dihydroxy-compound 19 (Scheme 3), and c) fermentative reductions of 6-oxo-isophorone derivatives (Schemes 4 and 5). - The absolute configurations of the two intermediates 12 and 13 (Scheme 2) have been confirmed by X-ray analysis.The final steps leading to the enantiomeric astaxanthins are identical with those described for optically inactive astaxanthin .
- Zell, Reinhard,Widmer, Erich,Lukac, Teodor,Leuenberger, Hans Georg Wilhelm,Schoenholzer, Peter,Broger, Emil A.
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p. 2447 - 2462
(2007/10/02)
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- Beitrag zur Analytik und Synthese von 3-Hydroxy-4-oxocarotinoiden
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(3RS,3'RS)-Astaxanthin (=3,3'-dihydroxy-β,β-carotene-4,4'-dione, 1:1-mixture of racemate and meso-form; 1) can be separated into its optical isomers (3S,3'S)-1a, (3R,3'R)-1b and meso-(3R,3'S)-1c via the corresponding diastereomeric di-(-)-camphanates.Some aspects of the configurational stability of astaxanthin are discussed. - HPLC. analysis of the (-)-camphanates of 3-hydroxy-4-oxocarotenoids provides, in suitable cases and supported by spectroscopic data, an analytical method for the simultaneous determination of constitution and chiralty.
- Mueller, Robert K.,Bernhard, Kurt,Mayer, Hans,Ruettimann, August,Vecchi, Max
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p. 1654 - 1664
(2007/10/02)
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