- 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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- Synthetic method of astaxanthin
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The invention provides a synthesis method of astaxanthin, and belongs to the technical field of pharmaceutical chemicals, a compound 21 and a compound 22 are firstly prepared, then the compound 21 and the compound 22 are used for synthesizing a compound 5, and then the compound 5 and a compound 6 are used for generating astaxanthin, raw materials are easy to obtain in the whole preparation process, the synthesis process is safe and easy to operate, and the product yield is high; the compound 21 is 4-halogenated-2-methyl-2-butene-1-methylal, the compound 22 is 2, 2, 4, 6, 6-pentamethyl-5, 6, 7, 7a-tetrahydro-5-methylene-1, 3-benzodioxolane, the compound 5 is 3-methyl-5-(2, 6, 6-trimethyl-3-oxo-4-hydroxy-1-cyclohexenyl)-2, 4-pentadienyl triphenyl phosphine halide, and the compound 6 is 2,7-dimethyl-2, 4, 6-octyl trienaraldehyde.
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- Method for preparing astaxanthin by oxidizing canthaxanthin
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The invention discloses a method for preparing astaxanthin by oxidizing canthaxanthin. The method comprises the following steps: dissolving a substrate canthaxanthin in an organic solvent; performingreacting by using a high-valence iodide as an oxidant to prepare a dialkoxy ketal compound; and hydrolyzing the ketal compound under acidic conditions to obtain astaxanthin. Therefore, problems of complex route and harsh conditions in the prior art are solved, and a safer and more practical method is provided for astaxanthin synthesis.
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Paragraph 0042-0054
(2020/10/20)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE ASTAXANTHIN
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PROBLEM TO BE SOLVED: To provide a method for producing an optically active 3(S),3'(S)-astaxanthin (I), with a 3(RS)-acetoxy-4-oxo-β-ionone derivative (IIab) of a racemate as the starting material. SOLUTION: The present invention provides a method for producing an optically active 3(S),3'(S)-astaxanthin, represented by formula (I), with a 3(RS)-acetoxy-4-oxo-β-ionone derivative (IIab) of a racemate as the starting material, the method including 8-9 separation and reaction steps. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
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- Fast regeneration of carotenoids from radical cations by isoflavonoid dianions: Importance of the carotenoid keto group for electron transfer
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Electron transfer to radical cations of β-carotene, zeaxanthin, canthaxanthin, and astaxanthin from each of the three acid/base forms of the diphenolic isoflavonoid daidzein and its C-glycoside puerarin, as studied by laser flash photolysis in homogeneous methanol/chloroform (1/9) solution, was found to depend on carotenoid structures and more significantly on the deprotonation degree of the isoflavonoids. None of the carotenoid radical cations reacted with the neutral forms of the isoflavonoids while the monoanionic and dianionic forms of the isoflavonoids regenerated the oxidized carotenoid. Electron transfer to the β-carotene radical cation from the puerarin dianion followed second order kinetics with the rate constant at 25 °C k2 = 5.5 × 109 M-1 s-1, zeaxanthin 8.5 × 109 M-1 s-1, canthaxanthin 6.5 × 1010 M-1 s-1, and astaxanthin 11.1 × 1010 M-1 s-1 approaching the diffusion limit and establishing a linear free energy relationship between rate constants and driving force. Comparable results found for the daidzein dianion indicate that the steric hindrance from the glucoside is not important suggesting the more reducing but less acidic 4′-OH/4′-O- as electron donors. On the basis of the rate constants obtained from kinetic analyses, the keto group of carotenoids is concluded to facilitate electron transfer. The driving force was estimated from oxidation potentials, as determined by cyclic-voltametry for puerarin and daidzein in aqueous solutions at varying pH conditions, which led to the standard reduction potentials E° = 1.13 and 1.10 V versus NHE corresponding to the uncharged puerarin and daidzein. For pH > pka2, the apparent potentials of both puerarin and daidzein became constants and were E° = 0.69 and 0.65 V, respectively. Electron transfer from isoflavonoids to the carotenoid radical cation, as formed during oxidative stress, is faster for astaxanthin than for the other carotenoids, which may relate to astaxanthins more effective antioxidative properties and in agreement with the highest electron accepting index of astaxanthin.
- Han, Rui-Min,Chen, Chang-Hui,Tian, Yu-Xi,Zhang, Jian-Ping,Skibsted, Leif H.
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scheme or table
p. 126 - 132
(2010/05/11)
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- 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 43
(2010/10/20)
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- METHOD FOR PRODUCING CAROTENOIDS
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The invention relates to a method for producing carotenoids. Said method is characterised in that a dialkoxy dialdehyde of general formula I, where R1 = C1-C6 alkyl, is reacted with a phosphonium salt of formula II in a double Wittig condensation, or with a phosphonate of formula III in a double Wittig-Horner condensation, whereby the substituents in formulas II and III independently of one another are defined as follows: R2 = IV; R3 represents aryl; R4 to R6 represent C1-C6 alkyl and X- represents an anion equivalent of an inorganic or organic acid.
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- Carotenoid Sulfates. 4. Syntheses and Properties of Carotenoid Sulfates
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Carotenoid sulfates have been prepared from 14 selected carotenols for spectroscopic characterization, studies of their stability in solution and their water solubility.Carotenoids containing sec non-allylic hydroxy groups provided sulfates stable in methanol solution, exemplified by zeaxanthin mono- and disulfate, alloxathin mono- and disulfate, fucoxanthin monosulfate, peridinin monosufate, capsorubin mono- and disulfate and astaxanthin mono- and disulfate.Acid catalyzed methanolysis of zeaxanthin disulfate gave zeaxanthin with complete retention of configuration.Enzymatic hydrolysis of alloxanthin monosulfate is reported.Less stable sulfates were obtained from sec vic diol type-, phenolic and tert-carotenols; caloxanthin, nostoxanthin, 3-hydroxyisorenieratene, 3,3'-dihydroxyisorenieratene, rhodovibrin, di-OH-lycopene and OH-chlorobactene.Acid catalyzed methanolysis of the tert caratenols proceeded via carbocations, judged by the solvolysis products characterized.Characteristic spectroscopic properties of carotenoid sulfates are pointed out.Water solubilities were studied.
- Hertzberg, Sissel,Liaaen-Jensen, Synnoeve
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p. 629 - 638
(2007/10/02)
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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 Oxo-isophoron. I. Modifizierung der Kienzle-Mayer-Synthese von (3S,3'S)-Astaxanthin
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An efficient synthesis of (3S,3'S)-astaxanthin (1a) in high yield and optical purity starting from (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone (4) is reported.The absolute configuration of 1a, previously derived from ORD. data, has been confirmed by X-ray analysis of 5, a derivate of 6-oxo-isophorone (2).The key features of the improved synthesis are the two-step conversion of 4 to the key intermediate (4S)-2,6,6-trimethyl-4-hydroxy-2-cyclohexen-1-one (14), a new method for the partial reduction of the sterically hindered triple bond of (S)-6-hydroxy-3-(5-hydroxy-3-methyl-3-penten-1-ynyl)-2,4,4-trimethyl-2-cyclohexen-1-one (32), and Wittig olefination of the dialdehyde 1,6-dimethyl-1,3,5-octatrienedial (38) using phosphonium salt 37 with a free hydroxyl group.
- Widmer, Erich,Zell, Reinhard,Lukac, Teodor,Casadei, Marco,Schoenholzer, Peter,Broger, Emil A.
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p. 2405 - 2418
(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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