JP2007509957A - Process for producing α- and β-cryptoxanthin - Google Patents

Abstract

  The present invention relates to a method for converting lutein and / or lutein ester into β-cryptoxanthin and α-cryptoxanthin suitable for consumption as dietary supplements by using a safe and environmentally friendly reagent. . In the first synthesis step, commercially available lutein and / or lutein esters are converted to a mixture of dehydrated products of lutein (anhydrolutein) in the presence of a catalytic amount of acid. The resulting anhydrolutein is then subjected to heterogeneous catalytic hydrogenation using group VIII transition elements in various organic solvents under atmospheric pressure hydrogen and β-cryptoxanthin (main product) and α -Converted to cryptoxanthin (small product). A novel feature of the present invention is the regioselective hydrogenation of anhydrolutein without changing the highly conjugated polyene chain of carotenoids.

Description

Background of the Invention
1. Field of the Invention The present invention is in the field of organic chemistry. The present invention relates to a mixture of (3R, 3R ′, 6′R) -lutein dehydrated product (hereinafter referred to as anhydrolutein) in various heterogeneous and homogeneous catalysts under mild conditions at atmospheric pressure. To a mixture of (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin by catalytic hydrogenation. Two other methods that can convert non-esterified lutein to anhydrolutein have also been developed. The invention also relates to a method for converting other lutein sources to anhydrolutein.

2. Technical Background β-cryptoxanthin is measured through plasma samples, but it is a large intervention trial at Oxford University (John JH, Ziebland S, Yudkin P, Roe LS, Neil HA. Effect of fruit. and vegetable consumption on plasma antioxidant concentrations and blood pressure: a randomized controlled trial.Lancet 2002; 359 (9322): 1969-74). To correlate β-cryptoxanthin levels with cardiovascular parameters, healthy and sick subjects have been investigated in various prospective trials (John et al; Appel L, Moore T, Obarzanek E, et al, A clinical trial of the effects of dietary patterns on blood pressure, N Engl J Med 1997; 336 (16): 1117-24). Cardiovascular markers such as LDL oxidation (Robert WG, Gordon MH, Walker AF. Effects of enhanced consumption of fruit and vegetables on plasma antioxidant status and oxidative resistance of LDL in smokers supplemented with fish oil. Eur J Clin Nutr 2003; 57: 1303-10), DNA synthesis (aortic cells) (Carpenter KL, Hardwick SJ, Albalani V, Mitchinson MJ. Carotenoids inhibit DNA synthesis in human aortic smooth muscle cells. FEBS Lett 1999; 447 (1): 17-20), Maron There appears to be a correlation with dialdehyde and early symptoms of myocardial infarction. Subjects with early symptoms of coronary artery disease (CAD), congestive heart failure (CHF), coronary heart disease (CHD), angina or myocardial infarction are all better compared to healthy age-appropriate subjects It has been shown to have low levels of β-cryptoxanthin (Meraji S, Abuja PM, Hayn M, et al. Relationship between classic risk factors, plasma antioxidants and indicators of oxidant stress in angina pectoris (AP) in Tehran. Atherosclerosis 2000; 150 (2): 403-12; Morris D, Kritchevsky S, Davis C. Serum caroterioids and coronary heart disease: the Lipid Research Clinics Coronary Primary Prevention Trial and Follow-up Study.JAMA 1994; 272: 1439-41; Ruiz Rejon F, Martin-Pena G, Granado F, Ruiz-Galiana J, Blanco I, Olmedilla B. Plasma status of retinol alpha- and gamma-tocopherols, and main carotenoids to first myocardial infaction: case control and follow-up study. Nutrition, 2002; 18 (1): 26-31; Dwyer JH, Paul-Labrador MJ, Fan J, Shircore AM, Bailey Merz CN, Dwyer KM, Progression of Carotid Intima-Media Thickness and Plasma Antioxidants: The Los Angels Atherosclerosis Study, Arterioscler Thromb Vasc Biol 2004; 24: 313-19; Wilson PW, Schaefer EJ, Lammi-Keefe CJ. Plasma retinol and plasma and lipoprotein tocopherol and carotenoid concentrations in healthy elderly participants of the Framingham Heart Study. Am J Clin Nutr 1997; 66 (4): 950-8). Inflammatory markers such as C-reactive protein and fibrinogen have also been associated with low β-cryptoxanthin levels (Kritchevsky SB, Bush AJ, Pahor M, Gross MD. Serum carotenoids and markers of inflammation in nonsmokers. Am J Epidermiol. 2000; 152 (11): 1065-71). Correlation with inflammation and heart disease is a relatively new area of research. Currently, there are no products in the dietary supplement market that have significant levels of β-cryptoxanthin or that contain β-cryptoxanthin as a major component.

  There are also some preliminary studies that looked at the effects of β-cryptoxanthin on bone growth and inhibition of bone resorption. In vitro studies have shown positive effects of β-cryptoxanthin on increasing bone calcium and enhancing bone alkaline phosphatase (Yamaguchi, M, Uchiyama, S. Effect of carotenoid on calcium content and alkaline phosphatase activity in rat femoral tissues in vitro: the unique anabolic effect of beta-cryptoxanthin Biol.Pharm.Bull 2003; 26 (8): 1188-91) (Uchiyama, A, Yamaguchi, M. Inhibitory effect of beta cell formation in mouse marrow cultures.Biochem.Pharmacol.2004; 67: 1297-13-5). Oral studies in rats have shown similar results. (Uchiyama, S, Sumida, T, Yamaguchi, M. Oral administration of beta-cryptoxanthin induces effects on bone components in the femoral tissues of rats in vivo. Biol. Pharm. Bull. 2004; 27 (2): 232-5. The PCT application has been filed for these findings (Yamaguchi, M. Osteogenesis promoter containing β-cryptoxanthin as the active ingredient PCT WO 2004/037236 A1).

  The present invention relates to commercially available (3R, 3′R, 6′R) -lutein containing 5% (3R, 3R ′)-zeaxanthin in two steps with (3R) -β-cryptoxanthin and ( An improvement to the method described in PCT US03 / 23422, which is converted to a mixture of 3R, 6′R) -α-cryptoxanthin, which is incorporated herein by reference. In the first step according to PCT US03 / 23422, (3R, 3′R, 6′R) -Lutein reacts with alcohol used as solvent in the presence of catalytic amounts of acid between 45-50 ° C. This gives the corresponding 3′-alkyl ether of lutein. Water and additional acid are then added to the mixture and the temperature is increased to 78-88 ° C. to quantitatively convert the resulting lutein 3′-alkyl ether to a mixture of anhydroluteins I, II and III. (Scheme 1 in FIG. 1). At the beginning of this conversion, anhydrolutein I is the major product and anhydrolutein II and III are minor products. If heating is continued at 78-88 ° C., anhydroluteins I and II are partially isomerized to anhydrolutein III in 7-20 hours, depending on the nature of the alcohol. In the second step of PCT US03 / 23422, the resulting product is rich in anhydrolutein and is about 1 to 5 hours at ambient temperature in a chlorinated solvent, about 1.3 equivalents of a hydride donor and about 3.5 to about strong organic acid. When reacted with 4 equivalents, E / Z- (3R) -β-cryptoxanthin, a mixture of E / Z- (3R, 6′R) -α-cryptoxanthin, and a small amount of unreacted anhydrolutein I and A mixture consisting of II and the recovered E / Z- (3R, 3′R) -zeaxanthin are obtained.

  The present invention provides a separate route to the second step of PCT US03 / 23422 to produce (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin from anhydrolutein, Omit the use of chlorinated solvents and reagents such as trifluoroacetic acid and borane-amine complexes. This is achieved by heterogeneous or homogeneous catalytic hydrogenation of anhydrolutein according to the scheme shown in FIG.

The present invention also provides a first conversion of (3R, 3′R, 6′R) -lutein to anhydrolutein to reduce the amount of solvent used and increase the purity and stability of the product. Improve one process.
Although all of the above methods use non-esterified lutein as the starting material, the present invention further provides (3R) -β-cryptoxanthin and (3R, 6′R) -α-crypto by catalytic hydrogenation. In order to produce anhydrolutein that can be converted to xanthine, two other methods have been developed that can use a mixture of esterified lutein as starting material.

SUMMARY OF THE INVENTION In an attempt to avoid the use of chlorinated solvents and reagents that can be toxic to humans, the use of (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin from anhydrolutein An alternative method for the second step of partial synthesis was developed. This is achieved by heterogeneous or homogeneous catalytic hydrogenation of anhydrolutein. Catalytic hydrogenation is widely used in the pharmaceutical and food industries and provides an economical route to products that can be used safely by humans. There are numerous literature examples dealing with heterogeneous and homogeneous hydrogenation of cycloalkenes and cyclodienes (H. Takaya, R. Noyori in Comprehensive Organic Synthesis, Eds. BM Trost and I. Fleming, Pergamon, Oxford). 1991, Vol 8, pp417-470). To date, however, there is no literature reporting on the regioselective catalytic hydrogenation of carotenoids. This is mainly due to the presence of highly conjugated polyene chains in carotenoids that are readily susceptible to hydrogenation and, as a result, it is difficult to control the regioselectivity of the process. Nevertheless, the present invention provides (3R) -β-cryptoxanthin and (3) by heterogeneous and homogeneous catalytic hydrogenation of anhydrolutein with a wide range of catalysts in various solvents under carefully controlled conditions. Mixtures of 3R, 6′R) -α-cryptoxanthin can be produced with moderate to excellent selectivity and yield.

  Thus, in another embodiment, the present invention provides an anhydrolutein-rich anhydrolutein group VIII supported on carbon or alumina in various organic solvents at temperatures ranging from -15 ° C to 40 ° C. Is converted to a mixture of (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin by heterogeneous catalytic hydrogenation using a transition element such as platinum, palladium or rhodium. Of these catalysts, platinum supported on alumina gives the highest yields of (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin.

Similarly, the present invention shows that some catalysts also promote regioselective catalytic hydrogenation of anhydrolutein, with moderate yields of (3R) -β-cryptoxanthin and (3R, 6 ′ A mixture of R) -α-cryptoxanthin is produced. However, depending on the nature of the catalyst and the reaction conditions, approximately 30-82% anhydrolutein remains unreacted. Homogeneous catalysts include transition metal complexes such as palladium acetylacetonate, tris (triphenylphosphine) rhodium (I) chloride [Rh (Ph ₃ P) ₃ Cl] (Wilkinson catalyst), (tricyclohexylphosphine) (1, 5-cyclooctadiene) pyridine iridium (I) hexafluorophosphate [(C ₆ H ₁₁ ) ₃ P [C ₈ H ₁₂ ] [C ₅ H ₅ N] Ir ⁺ PF ₆ ⁻ ] (Crabtree catalyst) and (1 , 5-cyclooctadiene) bis (methyl diphenyl phosphine) iridium (I) hexafluorophosphate _{[C 8 H 12] [(} MePh 2 P) 2] Ir + PF 6 - may be. Of these, hydrogenation of anhydrolutein with a calculated amount of Wilkinson's catalyst produces (3R) -β-cryptoxanthin and (3R, 6'R) -α-cryptoxanthin in nearly quantitative yields. . Various formulations of commercially available lutein used as starting materials in the present invention also contain approximately 5-9% (3R, 3′R) -zeaxanthin. This carotenoid remains unreacted through the series of reactions described above and is recovered as a minor component in the final product.

  The above method uses non-esterified lutein from a saponified extract of marigold oleoresin as a starting material. However, the present invention is not limited to lutein fatty acid esters (e.g. lutein bispalmitate, lutein bismyristate, lutein 3-myristate 3′-palmitate, lutein 3-palmitate 3′-myristate, as shown in the scheme of FIG. ) Containing two other routes from unsaponified extract of marigold oleoresin to anhydrolutein. Lutein esters in marigold oleoresin are accompanied by approximately 5-9% zeaxanthin fatty acid esters (eg, zeaxanthin bismyristate, zeaxanthin 3-myristate 3'-palmitate, zeaxanthin bispalmitate). Production of anhydrolutein from an unsaponified extract of marigold oleoresin is accomplished by acid-catalyzed transesterification of the lutein ester with an alcohol at an elevated temperature, preferably about 45-50 ° C. Under these controlled conditions, the 3'-position acyl ester of the lutein ester undergoes transesterification preferentially, whereas the 3-position acyl ester group remains unchanged. In the presence of an alcohol and a catalytic amount of acid, both the transesterification and the etherification at the 3'-position are carried out (see scheme in Fig. 2). The resulting lutein 3-acyl ester 3'-alkyl ether can then be converted to anhydrolutein at an elevated temperature, preferably in the range of 78-88 ° C. Alternatively, lutein 3'-alkyl ether is obtained by subjecting lutein 3-acyl ester 3'-alkyl ether to saponification to hydrolyze the 3-position acyl ester. Lutein 3'-alkyl ether can then be converted to anhydrolutein according to PCT US03 / 23422. When the obtained anhydrolutein is catalytically hydrogenated according to the method of the present invention, a mixture of (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin can be obtained. (3R, 3'R) -zeaxanthin ester present as a minor component in the starting material is converted to non-esterified (3R, 3'R) -zeaxanthin, but otherwise remains unchanged throughout the process .

  The present invention also improves the process of converting lutein to anhydrolutein by reducing the amount of solvent and increasing the purity and stability of the product. In addition to using dry lutein powder as a starting material, the present invention further improves this carotenoid over anhydrolutein using a lutein-containing product (hereinafter referred to as wet lutein) having a significant amount of moisture content. Can be converted in high yield. The wet lutein used in this disclosure includes any lutein-containing product that contains more water than dry lutein powder. US Patent No. Products manufactured as described in US Pat. No. 5,648,564 are specifically included in the term wet lutein when water is added to the saponified oleoresin and some amount of liquid is removed by centrifugation. Kemin Industries (Des Moines, Iowa) sells OroGLO® liquid products, which are also included in the term wet lutein.

  (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin can be used as dietary supplements, nutritional ingredients, or as food coloring additives. With the availability of these carotenoids, scientists have been able to demonstrate the powerful chemistry of these compounds in terms of neuroprotective agents, bone health promotion, and prevention of cancer, cardiovascular disease and macular degeneration. It is possible to study the efficacy of preventive prevention.

Detailed Description of Preferred Embodiments According to earlier application PCT US03 / 23422, commercially available (3R, 3'R, 6'R)-containing about 5% (3R, 3'R) -zeaxanthin Lutein can be dehydrated with strong mineral acids at temperatures of 50-60 ° C. to produce the main product anhydrolutein I and minor products anhydrolutein II and III. However, when the temperature is raised to 78-88 ° C., anhydrolutein I slowly isomerizes to anhydrolutein III. This is the preferred starting material for the second step of the method described above (PCT US03 / 23422). Therefore, the product resulting from this isomerization is a mixture of anhydrolutein, where anhydrolutein III is the main product, the remainder is anhydrolutein I and anhydrolutein II and a small amount of unreacted zeaxanthin. Yes (Figure 1). In the second step of PCT US03 / 23422, the mixture is subjected to ionic hydrogenation with a strong acid and a hydride ion donor at ambient temperature to give (3R) -β-cryptoxanthin and (3R, 6′R) -α-cryptoxanthin is produced in excellent yield.

The present invention relates to a mixture of anhydroluteins having an anhydrolutein I: anhydrolutein II: anhydrolutein III ratio of approximately 1.4: 1.0: 10 in various solvents under mild conditions at atmospheric pressure or pressure. It relates to catalytic hydrogenation which converts to a mixture of β-cryptoxanthin and α-cryptoxanthin by heterogeneous and homogeneous catalytic hydrogenation. Heterogeneous catalysts include group VIII transition elements such as platinum (Pt) (5%) supported on alumina, Pt (5% or 10%) supported on activated carbon, palladium (Pd ) (Pd / C, 5% or 10%), Pd supported on alumina (5% or 10%), Pd supported on calcium carbonate (Pd / CaCO ₃ , 5%), on polyethyleneimine / SiO ₂ It can be selected from Pd 3% (Royer Pd catalyst) or rhodium (Rh) supported on alumina (5%). Of these, the best results were obtained when using Pt supported on alumina to convert a mixture of anhydroluteins to β-cryptoxanthin and α-cryptoxanthin in yields ranging from 77 to 99% of total carotenoids. Is achieved.

Homogeneous catalysts include transition metal complexes such as palladium acetylacetonate, tris (triphenylphosphine) rhodium (I) chloride [Rh (Ph ₃ P) ₃ Cl] (Wilkinson catalyst), (tricyclohexylphosphine) (1, 5-cyclooctadiene) pyridine iridium (I) hexafluorophosphate [(C ₆ H ₁₁ ) ₃ P [C ₈ H ₁₂ ] [C ₅ H ₅ N] Ir ⁺ PF ₆ ⁻ ] (Crabtree catalyst) and (1 , 5-cyclooctadiene) bis (methyl diphenyl phosphine) iridium (I) hexafluorophosphate _{[C 8 H 12] [(} MePh 2 P) 2] Ir + PF 6 - may be.

All heterogeneous and homogeneous hydrogenation reactions are advantageously carried out under atmospheric pressure of hydrogen. However, a heterogeneous catalytic hydrogenation reaction carried out at Pt under a hydrogen pressure of 40-60 psi produces results comparable to hydrogenation carried out at atmospheric pressure. When heterogeneous catalytic hydrogenation of anhydrolutein is carried out with catalyst: substrate 1.4-5.0 mol% (0.5-1.8 wt%), (3R) -β-cryptoxanthin and (3R, 6′R) -α- This produces moderate to excellent yields of cryptoxanthin. The homogeneous catalytic hydrogenation reaction requires 3-10 mol% of catalyst: substrate to obtain the desired product in low to moderate yields. For this, Wilkinson's catalyst [Rh (Ph ₃ P) ₃ Cl] converts anhydrolutein into (3R) -β-cryptoxanthin and (3R, 6'R) -α-cryptoxanthin in almost quantitative yield. There is an exception to convert. Depending on the nature of the catalyst and solvent, the temperature, pressure and duration of the reaction can vary. A wide range of solvents in which anhydrolutein is soluble can be used for this catalytic hydrogenation. These solvents include ethyl acetate, acetone, tetrahydrofuran (THF), t-butyl methyl ether (TBME), toluene and chlorinated solvents (dichloromethane, chloroform, 1,2-dichloroethane). It is not limited. The temperature range for heterogeneous catalytic hydrogenation with Group VIII transition elements is -15 to 100 ° C, preferably about -15 to about 40 ° C. However, for Pd 3% supported on polyethyleneimine / SiO ₂ (Royer Pd catalyst), the reaction is preferably carried out at a temperature in the range of about 20-80 ° C, most preferably between about 45-50 ° C. Do. Homogeneous catalytic hydrogenation can be performed over a wide range of temperatures and is usually performed at ambient temperature, except for reactions carried out with palladium acetylacetonate, which is preferably performed between about 45-50 ° C. .

  The starting material comprises a mixture of anhydroluteins I, II and III, but is commercially available (3R, 3′R,) by modifying the method described in previously filed PCT application US03 / 23422. 6'R) -Lutein can be produced. This improved method involves the use of ethers (such as, but not limited to, THF, t-butyl methyl ether, ethyl ether, diisopropyl ether) as co-solvents to increase the solubility of lutein. Reduce the amount of alcohol. Suitable alcohols include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, 1-pentanol (n-amyl alcohol), 2-pentanol, n- Examples include, but are not limited to, hexyl alcohol, n-octyl alcohol, ethylene glycol, and propylene glycol. Of course, if the cryptoxanthin produced by the methods described herein is edible, the use and selection of ethers and alcohols or alcohol mixtures is related to food safety and regulation. Will be affected. An advantage of the method described herein is that no chlorinated toxic solvents are used.

  In another embodiment, the present invention shows that dehydration of lutein can also be performed using wet lutein, as opposed to dry lutein powder. This alternative eliminates the use of co-solvents and at the same time reduces the amount of alcohol used for dehydration of lutein. Wet lutein contains a substantial amount of water and has a lutein content of approximately 38%. (This US patent is hereby incorporated herein by reference). In subsequent steps, the wet lutein is dried to yield a dry lutein powder. Also, anhydroluteins produced by acid-catalyzed dehydration of wet or dry lutein with hydrochloric acid should be more stable as opposed to products obtained using other mineral acids such as sulfuric acid and phosphoric acid. Was found. Organic acids such as trifluoroacetic acid and trichloroacetic acid can also be used. At the end of the dehydration reaction, a sufficient amount of an inorganic base such as sodium hydroxide or potassium hydroxide is added to neutralize the acid used in the dehydration reaction and adjust its pH to 7. The addition of an inorganic base can also contribute to an increased stability of anhydrolutein upon storage.

  In another embodiment, the present invention further provides that anhydrolutein is a precursor of β-cryptoxanthin and α-cryptoxanthin and can be produced directly from lutein esterified by acid-catalyzed transesterification. Shown (Figure 2). Lutein esterified with fatty acids, such as myristic acid and palmitic acid, is abundant in certain natural products, especially crude extracts of marigold flowers, and is an economic for the synthesis of anhydrolutein. Can be a profitable raw material.

Reagents and starting materials In the present invention, four types of (3R, 3′R, 6′R) -lutein can be used as starting materials, which are 1) commercially available dry (3R , 3'R, 6'R) Lutein powder; 2) Refined product of lutein powder with a total carotenoid content greater than 97% obtained by recrystallization of lutein powder; 3) Has a slight (not slight) lutein content Wet lutein containing water; and 4) lutein fatty acid esters (examples include lutein bismyristate, lutein bispalmitate, lutein 3-myristate 3 ′ palmitate and lutein 3-palmitate 3′-myristate) Marigold oleoresin containing a mixture of Marigold oleoresin is manufactured from marigold flower extract and, of course, typically 3% (w / w) lutein after saponification, depending on the lutein content of the marigold flower. Containing. Saponified marigold oleoresin is also a precursor to wet lutein products used to produce lutein powder. Saponified marigold oleoresin contains (3R, 3′R) zeaxanthin which remains unreacted throughout all the steps of the process described in the present invention. Depending on the source of marigold, saponified marigold oleoresin is approximately between 5-9% of (3R, 3'R, 6'R) -lutein (91-95%) Contains (3R, 3'R) -zeaxanthin. The reaction described in the present invention can be carried out using any combination of these four types of retainins. All of these starting materials are available from Kemin Foods (Des Moines, Iowa). All other reagents, solvents and hydrogenation catalysts used in the present invention are commercially available and can be used without further purification.

1. Process for the preparation of anhydrolutein by acid-catalyzed dehydration of (3R, 3'R, 6'R) -lutein powder and wet lutein In a typical experiment, n-propanol (100 ml) and ethers such as tetrahydrofuran (THF , 10 ml) of dry lutein powder (according to HPLC, 6.0 g of 85% total carotenoid containing approximately 95% lutein and 5% zeaxanthin; approximately 5.10 g, 8.98 mmol) in 1 ml of 10% hydrochloric acid (v / v) and the mixture is heated to 45-50 ° under a nitrogen atmosphere to give lutein 3′-propyl ether. Water (100 ml) and 8 ml of aqueous HCl (18-19%) solution are added and the temperature of the reaction mixture is raised to 78-88 ° C. After refluxing in n-propanol for 12-17 hours, the product is cooled to ambient temperature and 20 ml of 10% aqueous sodium hydroxide (wt / v) is added. The reddish crystals of anhydrolutein rich in anhydrolutein III are then removed by filtration. Wash the solid with 40 ml of ethanol / water 1/1 solution (v / v) followed by 30 ml ethanol and 10 ml hexane and dry under high vacuum to give 4.5 g of product. It is done. The yield of this reaction, based on the total carotenoid content of the dried product from various experiments, ranges from 65% to 75%. The final product consists of more than 80% anhydrolutein III, the rest being anhydrolutein I and II and a small amount of (3R, 3′-R) -zeaxanthin. As shown by HPLC, anhydrolutein is not present in significant amounts of the Z (cis) isomer in the crystallized product.

  In another embodiment, a suspension of 40 g wet lutein (38% lutein content) in n-propanol (100 ml), water (50 ml) and aqueous HCl (10 ml, 6N) was refluxed under a nitrogen atmosphere (88 Stir mechanically at ~ 90 ° C for nearly 16 hours. After cooling to room temperature, the acid is neutralized and the red crystals are collected by filtration and washed with water and alcohol. The dried product (13.7 g, total carotenoids) was composed of anhydrolutein in a ratio of anhydrolutein I: anhydrolutein II: anhydrolutein III (1.9: 1.0: 10.9) ) -Zeaxanthin.

  Accordingly, the present invention is enriched in anhydrolutein III by reacting dried lutein or wet powder with alcohol in the presence of a catalytic amount of acid at a temperature above ambient temperature, preferably 78-88 ° C. It relates to an improved process for obtaining a mixture of anhydroluteins.

  Alternatively, the present invention uses a small amount of ether (THF, diethyl ether, diisopropyl ether, t-butyl methyl ether) as a co-solvent for (1 to 1.7 ml / g lutein) and (3R, 3′R, 6′R This relates to an improved method of increasing the solubility of lutein and allowing the reaction to proceed with a small amount of alcohol (15-47 ml per gram of lutein).

  Alternatively, the crystalline product is worked up and washed to give a mixture of anhydroluteins. In a preferred embodiment, product work-up and washing involves washing the crystalline product with a small amount of hydrocarbon solvent (pentane, hexane, petroleum ether) to remove any unsaturated hydrocarbons that may be present as by-products. And promoting the removal of alcohol and drying the final product.

2. Preparation of anhydrolutein by acid-catalyzed transesterification of lutein ester from marigold oleoresin As shown in the scheme of Figure 2, lutein ester undergoes acid-catalyzed transesterification in the presence of alcohol at high temperature to A mixture of hydroluteins I, II and III is produced. The present invention shows that the ester groups at the C-3 and C-3 ′ positions of lutein are not equally susceptible to transesterification. For example, a lutein ester (esterified with myristic acid and palmitic acid) dissolved in a hydrocarbon solvent or ether is controlled at 45-50 ° C. in n-propanol in the presence of a catalytic amount of mineral acid. The transesterification under conditions produces mainly lutein 3-myristate 3′-propyl ether and lutein 3-palmitate 3′-propyl ether in about 21 hours. This is confirmed by monitoring the product formation before and after saponification by HPLC. Prior to saponification, HPLC clearly shows the absence of lutein, lutein 3′-propyl ether and / or anhydrolutein, whereas when the product is saponified, exclusively lutein 3′-propyl ether is obtained. can get. In contrast to the C-3 ester group, which does not have an allyl group and remains unchanged, the C-3 ′ α, β-unsaturated ester group of the lutein ester is susceptible to transesterification. There is a high possibility of having sex. Thus, under controlled conditions at ambient temperature or higher temperatures below 50 ° C., the transesterification of lutein esters yields lutein 3-acyl esters, which in the presence of catalytic amounts of acid and n-propanol are C- Upon etherification at 3 ′, the lutein 3-acyl ester 3′-propyl ether is obtained. When the temperature is higher than 50 ° C., the ester group at the C-3 position also undergoes acid-catalyzed transesterification to give lutein 3′-propyl ether. At temperatures above 50 ° C., transesterification, as well as the disappearance of n-propanol from lutein 3′-propyl ether, results in a mixture of anhydroluteins I, II and III. Alternatively, in the present invention, lutein 3-acyl ester 3′-propyl ether is isolated and the product is subjected to saponification to produce lutein 3′-propyl ether. The compound is then converted to anhydrolutein according to the procedure described in PCT US03 / 23422.

Accordingly, the present invention provides a process for reacting a lutein ester dissolved in a hydrocarbon or ether with a catalytic amount of an acid in the presence of an alcohol to obtain a mixture of anhydrolutein, wherein the lutein ester is converted into a catalyst. Reacting with an alcohol in the presence of a quantity of acid at ambient temperature to an elevated temperature below 60 ° C., preferably 45-60 ° C., to give a mixture of lutein 3-acyl ester 3′-alkyl ethers, water and additional The process comprising the step of converting the mixture to anhydrolutein I, II and III by increasing the temperature, preferably to 78-88 ° C. In a preferred embodiment, the reaction is
a) In a suitable amount of hydrocarbon solvent (e.g. pentane, hexane, petroleum ether) or ether (e.g. THF, diethyl ether, diisopropyl ether, t-butyl methyl ether) (about 2 ml / g of marigold oleoresin) Dissolve commercially available lutein ester containing a small amount of zeaxanthin ester from marigold oleoresin in alcohol (1.2 ml per gram of marigold oleoresin) and a catalytic amount of acid in alcohol [eg per gram of marigold Adding about 0.1 ml of 10% hydrochloric acid in alcohol (v / v)] to obtain a mixture;
b) The mixture is stirred at ambient temperature to 60 ° C., preferably 60 ° C. for about 6 to 8 hours to give lutein 3-myristate 3′-alkyl ether, lutein 3-palmitate 3′-alkyl ether and anhydro Obtaining a mixture of myristyl and palmityl esters of lutein I, II and III;
c) Add water (eg about 1.2 ml per gram of marigold oleoresin) and aqueous acid solution (about 0.1 ml of 10% aqueous hydrochloric acid (v / v) per gram of marigold oleoresin) and mix the mixture for 22 hours. Heating to 78-90 ° C. to obtain anhydroluteins I, II and III;
d) cooling the product to ambient temperature, washing the product with water and removing the organic phase;
e) hydrolyzing the organic phase for 2-3 hours at ambient temperature using an alcohol solution of an inorganic base (eg KOH / methanol, NaOH / methanol);
f) washing the organic phase with water and evaporating most of the solvent to obtain a concentrated residue;
g) Crystallize the anhydroluteins I-III and a small amount of zeaxanthin from the residue by adding a 1/1 solution (v / v) of alcohol in water, preferably methanol or ethanol in water, and filter the crystals by filtration. Collecting and drying the product under high vacuum;
including.

In another embodiment, the lutein ester is converted to a mixture of lutein 3-myristate 3′-alkyl ether and lutein 3-palmitate 3′-alkyl ether under controlled conditions and the isolated product is: It is then subjected to alkaline hydrolysis to give lutein 3′-alkyl ether. In addition, it is converted to anhydrolutein at a temperature of 78-90 ° C. In a preferred embodiment, the reaction is
a) In a suitable amount of hydrocarbon solvent (eg pentane, hexane, petroleum ether) or ether (eg THF, diethyl ether, diisopropyl ether, t-butyl methyl ether) (about 2 ml per gram of marigold oleoresin) A commercially available lutein ester containing a small amount of zeaxanthin ester from marigold oleoresin is dissolved and alcohol (1.2 ml per gram of marigold oleoresin) and a catalytic amount of acid in alcohol [eg, per gram of marigold, Adding about 0.1 ml of 10% hydrochloric acid in alcohol (v / v) to obtain a mixture;
b) The mixture is stirred at ambient temperature to 50 ° C., preferably 45 to 50 ° C., for about 21 hours to produce a mixture of lutein 3-myristate 3′-alkyl ether and lutein 3-palmitate 3′-alkyl ether. Obtaining step;
c) cooling the product to ambient temperature and hydrolyzing the mixture with an alcohol solution of an inorganic base (eg KOH / methanol, NaOH / methanol) at ambient temperature for 2-3 hours;
d) washing the saponified product with water and evaporating most of the solvent to obtain a concentrated residue;
e) Lutein 3′-alkyl ether and a small amount of zeaxanthin are crystallized from the residue by adding a 1/1 solution (v / v) of alcohol in water, preferably methanol or ethanol in water, and the crystals are collected by filtration The step of:
f) Suspension of crystalline lutein 3′-alkyl ether in an appropriate amount (about 3 ml) of alcohol and water (about 3 ml) and a catalytic amount of an aqueous acid solution (e.g. 18-19% hydrochloric acid (v / v ) About 0.2 ml) to obtain a mixture;
g) stirring the mixture at 78-90 ° C. for about 18 hours to obtain a mixture of anhydroluteins I, II and III;
h) allowing the product to cool to ambient temperature, neutralizing the acid with an inorganic base, and extracting the product with ether (eg, ethyl ether, diisopropyl ether, t-butyl methyl ether);
i) washing the organic phase with water and evaporating most of the solvent to obtain a concentrated residue;
j) Crystallization of the anhydrolutein I-III and a small amount of zeaxanthin from the residue by adding a 1/1 solution (v / v) of alcohol in water, preferably methanol or ethanol in water, and filtering the crystals Collecting and drying the product under high vacuum;
including.

3. Heterogeneous Catalytic Hydrogenation of Anhydrolutein with Group VIII Transition Elements The present invention relates to Group VIII transition elements in various organic solvents at temperatures ranging from -15 ° C to 40 ° C under hydrogen at atmospheric pressure. Relates to a process for hydrogenating a mixture of anhydrolutein to β-cryptoxanthin and α-cryptoxanthin in the presence of a catalytic amount of (FIG. 1). The catalyst is platinum (Pt) (5%) supported on alumina, Pt (5% or 10%) supported on activated carbon, palladium (Pd) (Pd / C, 5% or 10%) supported on activated carbon. ), Pd supported on alumina (5% or 10%), Pd supported on calcium carbonate (Pd / CaCO ₃ , 5%), Pd ₃ % supported on polyethyleneimine / SiO ₂ (Royer Pd catalyst) or Rhodium (Rh) (5%) supported on alumina may be used. The results of hydrogenation experiments with these catalysts are summarized in Tables 1, 2 and 3. The best yield and regioselectivity for the hydrogenation of anhydrolutein to β-cryptoxanthin and α-cryptoxanthin was achieved using Pt (5%) supported on alumina in ethyl acetate. Reaction conditions, such as temperature and the amount of catalyst used, play an important role in the rate and time of hydrogenation. Catalyst '(Pt / alumina): If the substrate is 1.8 wt% (5 mol%), the reaction proceeds even at -15 ° C, but at a much slower rate, the reaction requires overnight experimentation . Using the same mole% (5%) as catalyst: substrate, the reaction can be completed within 4 hours at 0 ° C. and can be completed in 2 hours at ambient temperature. However, when the mol% of catalyst: substrate drops from 5 mol% to 1.4-2.2 mol%, the rate of hydrogenation decreases and the reaction is best performed at 40 ° C. and is completed in 10-26 hours. The nature of the solvent does not appear to affect the hydrogenation results. In the present invention, ethyl acetate is selected as the optimal solvent because of its safety attributes and its wide acceptance for use in the production of food additives and dietary supplements. The results listed in Table 1 also indicate that the hydrogenation conditions have little or no effect on the overall reaction yield. The overall yield of anhydrolutein hydrogenation is in the range of 85-99%, except that the reaction is carried out in acetone. The purity of anhydrolutein in the range of 45% to 75% also does not affect the hydrogenation yield or results (Table 1). Hydrogenation of an anhydrolutein mixture with Pt / alumina in ethyl acetate also yields higher yields of β-cryptoxanthin compared to α-cryptoxanthin. From the viewpoint of the vitamin A activity of β-cryptoxanthin, this is an important feature of the present invention.

  Large-scale hydrogenation of anhydrolutein with Pt (5%) supported on alumina was also found to be consistent and yielded high yields of cryptoxanthin as the main product. Here, the ratio of β-cryptoxanthin: α-cryptoxanthin ranged from 5: 1 to 3: 1. The results of these experiments are summarized in the first three data columns in Table 2. Large scale experiments were also conducted. A Pfaudler reactor was charged with a mixture of anhydrolutein (400 g, 47.7% total carotenoids, 31.5% anhydrolutein III), platinum supported on alumina (5%) (40 g) and ethyl acetate (14 liters). The reaction system was purged with nitrogen followed by hydrogen. The mixture is stirred under 40 ° C. and 40 PSI hydrogen. After 14 hours, the reaction mixture is cooled to ambient temperature and filtered through celite. The filtrate is concentrated under reduced pressure at a temperature below 40 ° C. and the residue is crystallized from an ethyl acetate / ethanol / water solution. Dark orange crystals are collected by filtration. The wet product as an orange solid (800 g, total carotenoid purity 20.4%, total carotenoid yield 85.5%, β-cryptoxanthin purity 9.89%, β-cryptoxanthin yield 62.6% from anhydrolutein III) Obtained.

  Half of the wet product was lyophilized to give an orange solid (176 g, total carotenoid purity 41.0%, total carotenoid yield 75.6%, β-cryptoxanthin purity 19.2%, β-cryptoxanthin yield from anhydrolutein III 53.4%) is obtained. This consists of a mixture of β-cryptoxanthin: α-cryptoxanthin = 3: 1. HPLC also shows the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3'R) -zeaxanthin.

  The other half of the wet product was reslurried with ethanol / water. The orange solid is collected by filtration and dried in a tray dryer at 40 ° C. The dried product was obtained as an orange solid (170 g, total carotenoid purity 35.1%, total carotenoid yield 62.5%, β-cryptoxanthin purity 17.3%, β-cryptoxanthin yield 46.6% from anhydrolutein III) It is done. This consists of a mixture of β-cryptoxanthin: α-cryptoxanthin = 3: 1. HPLC also shows the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3'R) -zeaxanthin. The results of this experiment are summarized in the last data column of Table 2.

  In another embodiment, using Pd supported on carbon or alumina, Pd supported on lead poisoned calcium carbonate (Lindler catalyst) and Pd supported on polyethyleneimine / silica gel, A mixture of anhydroluteins can also be hydrogenated to β-cryptoxanthin and α-cryptoxanthin in low to moderate yields. Other than the hydrogenation reaction of anhydrolutein with Pd supported on polyethyleneimine / silica gel, which is best performed at 50 ° C., other Pd supported catalysts are extremely reactive and this conversion is Achieve at ℃. However, the regioselectivity of anhydrolutein hydrogenation using Pd as a catalyst is not as good as Pt, which is evident from β-cryptoxanthin and α-cryptoxin from various experiments summarized in Table 3. This is reflected in the yield of xanthine. These reactions involve various organic solvents in which anhydrolutein is soluble under atmospheric or high pressure of hydrogen (e.g., ethyl acetate, acetone, tetrahydrofuran (THF), diethyl ether, diisopropyl ether or t-butyl methyl ether, dichloromethane). 1,2-dichloroethane and chloroform, other ethers and other chlorinated solvents).

  When using Rh supported on alumina for hydrogenation of anhydrolutein, the reaction is best performed at 50 ° C., resulting in low yields of β-cryptoxanthin and α-cryptoxanthin, starting materials Most of it is lost under these conditions.

Thus, the present invention provides a mixture of anhydrolutein I, II, III rich in anhydrolutein III in various organic solvents under atmospheric or high pressure hydrogen, in catalytic amounts of group VIII transition elements, preferably Hydrogen in β-cryptoxanthin and α-cryptoxanthin in the presence of Pt supported on alumina at a temperature in the range of −15 ° C. to 100 ° C., preferably in the range of about −15 ° C. to about 50 ° C. It relates to the method of making. In a preferred embodiment, the reaction is
a) A suitable amount of an organic solvent (approximately 35 ml per gram of anhydrolutein), preferably ethyl acetate, having anhydrolutein having a purity in the range of 45-75% and 5% supported on alumina. Adding a catalytic amount of Pt (catalyst: substrate 1.4-2.2 mol%) to obtain a mixture;
b) replacing air with an inert gas, preferably argon, and then replacing the inert gas with hydrogen;
c) stirring the mixture under hydrogen at atmospheric pressure at -15 ° C to 50 ° C, preferably at about 40 ° C for about 10 to 26 hours to obtain a mixture of β-cryptoxanthin and α-cryptoxanthin ;
d) removing the catalyst by filtration through celite and concentrating the filtrate under reduced pressure at a temperature below 40 ° C. to obtain a concentrated residue containing β-cryptoxanthin and α-cryptoxanthin;
e) β-cryptoxanthin and α-cryptoxanthin are crystallized from the residue by adding a 1/1 solution (v / v) of alcohol in water, preferably methanol or ethanol in water, and the product is collected by filtration Drying the crystals at a temperature below 40 ° C. under high vacuum;
including.

4. Homogeneous catalytic hydrogenation of anhydrolutein The present invention relates to a mixture of anhydrolutein into β-cryptoxanthin and α-cryptoxanthin in the presence of catalytic amounts of several transition metal complexes. Relates to a process for hydrogenation in a yield of Homogeneous catalysts include transition metal complexes such as palladium acetylacetonate, tris (triphenylphosphine) rhodium (I) chloride [Rh (Ph ₃ P) ₃ Cl] (Wilkinson catalyst), (tricyclohexylphosphine) (1, 5-cyclooctadiene) pyridine iridium (I) hexafluorophosphate [(C ₆ H ₁₁ ) ₃ P [C ₈ H ₁₂ ] [C ₅ H ₅ N] Ir ⁺ PF ₆ ⁻ ] (Crabtree catalyst) and (1 , 5-cyclooctadiene) bis (methyl diphenyl phosphine) iridium (I) hexafluorophosphate _{[C 8 H 12] [(} MePh 2 P) 2] Ir + PF 6 - may be. All reactions are preferably carried out at ambient temperature under atmospheric pressure of hydrogen. The exception is a hydrogenation reaction using palladium acetylacetonate, preferably carried out at 45-50 ° C. Table 4 summarizes the results of hydrogenation experiments using these homogeneous catalysts.

Of the various homogeneous hydrogenation catalysts tried, Wilkinson's catalyst [(Ph ₃ P) ₃ RhCl] converts anhydrolutein to β-cryptoxanthin and α-cryptoxanthin in almost quantitative yield. The only regioselective hydrogenation of highly conjugated polyene systems reported in the literature on Wilkinson's catalyst is the hydrogenation of retinoid derivatives, ie 3,4-didehydro-9-cis-retinoic acid [Bennani, YI, Boehm, MFJ Org. Chem., 60 (5), 1195-1200, 1995]. To date, however, there are no literature reports or examples relating to the regioselective hydrogenation of carotenoids using either the heterogeneous or homogeneous catalysts described in the present invention or Wilkinson's catalyst. Hydrogenation of anhydrolutein with a homogeneous catalyst other than Wilkinson's catalyst yields β-cryptoxanthin and α-cryptoxanthin in low to moderate yields, and significant amounts of anhydrolutein remain unreacted .

Accordingly, the present invention further provides catalytic amounts of transition metal complexes of anhydrolutein III-rich anhydrolutein I, II, III in various organic solvents at atmospheric temperature under atmospheric pressure hydrogen, Preferably, the present invention relates to a method for hydrogenation to β-cryptoxanthin and α-cryptoxanthin in the presence of Wilkinson's catalyst [(Ph ₃ P) ₃ RhCl]. In a preferred embodiment, the reaction is
a) A suitable amount of an organic solvent (approximately 50 ml per gram of anhydrolutein), preferably ethyl acetate, with anhydrolutein having a purity in the range of 45-75% is dissolved in a stoichiometric amount of (Ph Adding ₃ P) ₃ RhCl (catalyst: substrate ratio of 2.2 mol equivalent) to obtain a mixture;
b) replacing air with an inert gas, preferably argon, and then replacing the inert gas with hydrogen;
c) stirring the mixture under atmospheric pressure hydrogen at ambient temperature for about 2 hours to obtain a mixture of β-cryptoxanthin and α-cryptoxanthin;
d) removing the catalyst by filtration through celite and concentrating the filtrate under reduced pressure at a temperature below 40 ° C. to obtain a concentrated residue containing β-cryptoxanthin and α-cryptoxanthin;
e) β-cryptoxanthin and α-cryptoxanthin are crystallized from the residue by adding a 1/1 solution (v / v) of alcohol in water, preferably methanol or ethanol in water, and the product is collected by filtration Drying the crystals at a temperature below 40 ° C. under high vacuum;
including.

  Appropriate modifications and adaptations to the methods and applications described herein will be apparent and can be made by those skilled in the art without departing from the scope of the invention or any of its embodiments. It will be easily understood. Although the invention has been described in detail so far, the invention will be more clearly understood by reference to the following examples. The following examples are for illustrative purposes only and are not intended to limit the invention in any way.

5. Preparation of Anhydrolutein I, II, III from Lutein and Lutein Esters Example A (3R, 3′R, 6′R) -Lutein (Purity 85) with hydrochloric acid in n-propanol and tetrahydrofuran (THF) %) Anhydrolutein I, II and III conversion into a 500 ml 3-neck flask equipped with a reflux condenser and a thermometer, (3R, 3'R, 6'R) -Lutein (85% lutein content 6.0g, approximately 5.10g, 8.98mmol). The flask was charged with 100 ml n-propanol and 10 ml tetrahydrofuran (THF), followed by 1 ml 10% hydrochloric acid in n-propanol [prepared from 0.1 ml concentrated HCl + 0.9 ml n-propanol]. . The flask was immersed in an oil bath and the mixture was heated to about 45-50 ° C. under a stream of nitrogen. The temperature must not exceed 55 ° C. Initially lutein is insoluble in n-propanol, but when the temperature reached 45-50 ° C., a dark red homogeneous solution was obtained. 30 minutes to 1 hour after the reaction temperature reached 45-50 ° C., the lutein was completely converted to lutein 3′-propyl ether.

  When 100 ml of water was added to the reaction mixture, a suspension of lutein 3'-propyl ether was obtained as yellow-orange crystals and the oil bath temperature was raised to reach the temperature of the reaction mixture to 90 ° C. When the reaction temperature approached the boiling point of THF (65-67 ° C.), the solvent was filtered off. Once all the THF was removed, 8.0 ml of 18-19% hydrochloric acid [prepared from 4 ml conc. HCl (36.5-38%) + 4 ml water] was added and the temperature of the mixture was raised to 90 ° C. (reflux temperature). As the temperature rose above 60 ° C., lutein 3'-propyl ether gradually changed to anhydroluteins I, II and III. However, at this point, anhydrolutein I was the main product. At 90 ° C., anhydrolutein I was gradually converted to anhydrolutein III. Anhydrolutein II remained stable. After 12-17 hours at 90 ° C., the oil bath was removed and the mixture was cooled to room temperature. 20 ml of 10% sodium hydroxide (wt / v) in water was added and stirring at room temperature was continued for 10 minutes. Subsequently, it filtered under reduced pressure on the Buchner funnel, and the reddish crystal of anhydrolutein was taken out. The crystalline product was washed successively with 40 ml ethanol / water 1/1 solution (v / v) followed by 30 ml ethanol and 10 ml hexane. This gave 5.0 g of red crystals of anhydrolutein that were well dried at this point. Further drying for 5 hours under high vacuum yielded 4.5 g of product (approximately 75% total carotenoids by UV-visible spectrophotometry). The product consisted of all-trans-zeaxanthin (minor amount), anhydrolutein with an anhydrolutein I: anhydrolutein: anhydrolutein III ratio of approximately 1.4: 1.0: 10. The filtrate from the above reaction was shown to contain a small amount of cis (Z) -carotenoid and have a pH of 7.

Example B Conversion of wet (3R, 3'R, 6'R) lutein (38% purity) with hydrochloric acid into anhydrolutein I, II and III in n-propanol
A suspension of lutein wet cake (40.0 g with 38% lutein content, approximately 15.2 g, 26.8 mmol) in 1-propanol (100 ml) and water (50 ml) was added to a condenser, mechanical stirrer, thermometer And mechanically stirred at 400 rpm in a 1000 ml four-necked flask equipped with a nitrogen inlet. An aqueous solution of hydrochloric acid (10.0 ml, approximately 6.0 N; 5.0 ml concentrated hydrochloric acid + 5.0 ml water) was added and the reaction mixture was heated to reflux under a nitrogen atmosphere. The progress of the reaction was monitored by HPLC. After 16 hours, the reaction mixture was cooled to room temperature, diluted with water (100 ml) and neutralized with 24 ml of 2.5N aqueous sodium hydroxide. Red crystals were collected by filtration followed by washing with 500 ml water and 20 ml cold ethanol and dried under high vacuum to give 18.5 g product (13.7 g total carotenoids, UV / visible 74% purity as measured by spectrophotometry). The ratio of anhydrolutein I: anhydrolutein II: anhydrolutein III = 1.9: 1.0: 10.9 gave 63% yield of anhydrolutein from lutein.

Example C Direct Conversion of Lutein Ester to Anhydrolutein I, II and III by Acid-Catalyzed Transesterification Marigold oleoresin (5 g) containing lutein ester (commercially available from Kemin Foods, Des Moines, Iowa) in hexane (10 ml) And treated with n-propanol (6 ml) and 0.5 ml of 10% hydrochloric acid (v / v) in propanol. The mixture was heated to 60 ° C. and the progress of the reaction was followed by HPLC (Khachik & Beecher, J. Chromatogr. 449: 119-133, 1988). After 8 hours, the carotenol fatty acid ester is converted into lutein 3-myristate 3′-propyl ether, lutein 3-palmitate 3′-propyl ether, and a mixture of myristic and palmitic esters of anhydroluteins I, II and III. Converted.

  Water (6 ml) and 0.5 ml of aqueous HCl (18-19%, v / v) were added and the temperature of the reaction mixture was gradually raised to distill off hexane. After removal of hexane, the temperature was raised to 90 ° C. and the mixture was refluxed in n-propanol for 22 hours. The reaction mixture was allowed to cool to ambient temperature and the acid was neutralized with a (10%) aqueous solution of NaOH. The product was extracted with t-butyl methyl ether (10 ml) and the aqueous layer was removed. The organic layer was treated with 10 ml methanolic KOH (10%) and stirred at ambient temperature for 2 hours. The saponified product was washed with water (3 × 10 ml), dried over sodium sulfate and most of the solvent was evaporated. The residue was crystallized from an ethanol / water 1/1 solution (v / v) to give 238 mg of red crystals. This was shown by HPLC to be 60% total carotenoids (142.8 mg) with a major portion of anhydrolutein I-III and a small amount of (3R, 3'-R) zeaxanthin.

Example D Conversion of Lutein Ester via Lutein 3′-Alkyl Ether to Anhydrolutein I, II and III Marigold oleoresin (5 g) containing lutein ester (commercially available from Kemin Foods) in hexane (10 ml) And treated with 0.5 ml of n-propanol (6 ml) and 10% hydrochloric acid in propanol (v / v). The mixture was heated to 45-50 ° C. and the progress of the reaction was followed by HPLC. After 21 hours, the reaction mixture was cooled to ambient temperature, 10 ml of methanolic KOH (10%) was added and stirring was continued for 2 hours at ambient temperature. The saponified product is washed with water (3 × 10 ml), dried over sodium sulfate and the majority of the solvent is evaporated. The residue was crystallized from an ethanol / water 1/1 solution (v / v) to give 263 mg of orange crystals. This was shown by HPLC to be 60% pure lutein 3′-propyl ether (157.8 mg) and a small amount of (3R, 3′R) -zeaxanthin. The crystalline product was suspended in n-propanol (3 ml) and water (3 ml) and treated with 0.2 ml of 18-19% aqueous hydrochloric acid (v / v). The mixture was heated to 90 ° C. (reflux temperature) and the progress of the reaction was followed by HPLC (Khachik et al. J. Chromatogr. Biomed. Application, 670: 219-233, 1995). After 18 hours, the mixture was cooled to room temperature. 0.6 ml of 10% aqueous sodium hydroxide solution (wt / v) was added and stirring at room temperature was continued for 10 minutes. The product was extracted with 10 ml t-butyl methyl ether and the aqueous layer was removed. The organic phase was washed with water (3 × 10 ml), dried over sodium sulfate and most of the solvent was evaporated. The residue was crystallized from a 1/1 (v / v) solution in ethanol / water. After drying under high vacuum, 236 mg of reddish crystals (approximately 60% total carotenoids by UV / visible spectrophotometry) were obtained. This shows that HPLC consists of all-trans-zeaxanthin (small amount) and anhydrolutein with an anhydrolutein I: anhydrolutein II: anhydrolutein III ratio of approximately 1.5: 1.0: 7.5. It was.

6. Heterogeneous catalytic hydrogenation reaction of anhydroluteins I, II, III Example A Anhydrolutein I, II with platinum supported on alumina (5%) in ethyl acetate at -5 ° C Catalytic hydrogenation of III (75% total carotenoids)
To a mixture of 75% total carotenoids (0.3 g, approximately 0.225 g) and platinum supported on alumina (80 mg, approximately 4.0 mg Pt) (5%) in a 60 ml glass reaction tube, 20 ml of ethyl acetate is added and the tube is Cool to −5 ° C. to 0 ° C. in an ice / salt bath. The tube was evacuated and filled with hydrogen several times and then sealed. The mixture was stirred at -5 ° C to 0 ° C and the progress of the reaction was followed by HPLC. After nearly 4 hours, HPLC shows almost complete conversion of anhydrolutein to the desired product. Approximately 30 ml of hydrogen (1.34 mmol) was required to complete the reaction. The product was warmed to ambient temperature and filtered through celite to remove the catalyst. At this point, the total carotenoid yield is UV-visible spectroscopy in hexane at 448 nm using the average extinction coeffeicent (E1% = 2511) for α-cryptoxanthin and β-cryptoxanthin. It was 89% as measured by photometric method. This was also confirmed by HPLC. The filtrate was concentrated under reduced pressure to a temperature below 40 ° C. and the residue was crystallized from 10 ml of a 1/1 ethanol / water solution. Dark orange crystals were collected by filtration, washed with 5 ml of cold ethanol and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.24 g, total carotenoid yield 70%) consisted of a 3: 1 mixture of β-cryptoxanthin and α-cryptoxanthin. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

Example B Catalytic hydrogenation of anhydroluteins I, II, III (75% total carotenoids) with platinum supported on alumina (5%) in ethyl acetate at -15 ° C.
To a mixture of 75% total carotenoids (0.3 g, approximately 0.225 g) and platinum supported on alumina (80 mg, approximately 4.0 mg Pt) (5%) in a 60 ml glass reaction tube, 20 ml of ethyl acetate is added and the tube is Cooled to -15 ° C in a low temperature freezer. The tube was evacuated and filled with hydrogen several times and then sealed. The mixture was stirred at -15 ° C and the progress of the reaction was followed by HPLC. After nearly 24 hours, HPLC showed almost complete conversion of the anhydrolutein to the desired product. The product was warmed to ambient temperature and filtered through celite to remove the catalyst. At this point, the total carotenoid yield was measured by UV-visible spectrophotometry in hexane at 448 nm using the average extinction coefficient (E1% = 2511) for α-cryptoxanthin and β-cryptoxanthin. And 90%. The filtrate was concentrated under reduced pressure to a temperature below 40 ° C. and the residue was crystallized from 10 ml of a 1/1 ethanol / water solution. Dark orange crystals were collected by filtration, washed with 5 ml of cold ethanol and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.29 g, total carotenoid yield 70%) consisted of a mixture cryptoxanthin in a ratio of β-cryptoxanthin: α-cryptoxanthin = 7: 3. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

Example C Catalytic hydrogenation of anhydroluteins I, II, III (45% total carotenoids) with platinum supported on alumina (5%) in ethyl acetate at 40 ° C.
A three-necked round bottom flask was equipped with a mechanical stirrer, thermometer and gas inlet. The flask was charged with anhydrolutein (20.0 g, 45% total carotenoids, 28% anhydrolutein III), alumina supported (5%) platinum (1.0 g) and ethyl acetate (700 ml). The air was replaced with argon and the mixture was heated to 40 ° C. with stirring at 500 rpm. Hydrogen was bubbled through the solution and the mixture was stirred at 40 ° C. After 26 hours, the reaction mixture was cooled to ambient temperature, diluted with 200 ml of ethyl acetate and filtered through celite. The filtrate was concentrated under reduced pressure at a temperature below 40 ° C., and the residue was crystallized from an ethyl acetate / ethanol / water solution. Dark orange crystals were collected by filtration and dried under high vacuum at temperatures below 40 ° C. The product was obtained as a red solid (18.3 g, total carotenoid yield 86%, yield of β-cryptoxanthin from anhydrolutein III is 48%). This consisted mainly of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 5: 1. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

Example D Catalytic hydrogenation of anhydroluteins I, II, III (49% total carotenoids) with platinum supported on alumina (5%) in ethyl acetate at 40 ° C.
A three-necked round bottom flask was equipped with a mechanical stirrer, thermometer and gas inlet. The flask was charged with anhydrolutein (20.0 g, 49% total carotenoids, 27% anhydrolutein III), alumina supported (5%) platinum (1.0 g) and ethyl acetate (700 ml). The air was replaced with argon and the mixture was heated to 40 ° C. with mechanical stirring at 500 rpm. Hydrogen was bubbled through the solution and the mixture was stirred at 40 ° C. After 21 hours, the reaction mixture was cooled to ambient temperature, diluted with 200 ml of ethyl acetate and filtered through celite. The filtrate was concentrated under reduced pressure at a temperature below 40 ° C., and the residue was crystallized from an ethyl acetate / ethanol / water solution. Dark orange crystals are collected by filtration and dried under high vacuum at temperatures below 40 ° C. The product was obtained as a red solid (18.2 g, 99% total carotenoid yield, 61% yield of β-cryptoxanthin from anhydrolutein III). This consisted mainly of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 4: 1. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

Example E Catalytic hydrogenation of anhydroluteins I, II, III (49% total carotenoids) with platinum supported on alumina (5%) in ethyl acetate at 40 ° C.
A three-necked round bottom flask was equipped with a mechanical stirrer, thermometer and gas inlet. The flask was charged with anhydrolutein (20.0 g, 49% total carotenoids, 27% anhydrolutein III), alumina supported (5%) platinum (1.5 g) and ethyl acetate (700 ml). The air was replaced with argon and the mixture was heated to 40 ° C. with mechanical stirring at 500 rpm. Hydrogen was bubbled through the solution and the mixture was stirred at 40 ° C. After 10 hours, the reaction mixture was cooled to ambient temperature, diluted with 200 ml of ethyl acetate and filtered through celite. The filtrate was concentrated under reduced pressure at a temperature below 40 ° C., and the residue was crystallized from an ethyl acetate / ethanol / water solution. Dark orange crystals were collected by filtration and dried under high vacuum at temperatures below 40 ° C. The product was obtained as a red solid (18.2 g, total carotenoid yield 94%, β-cryptoxanthin yield from anhydrolutein III is 75%). This consisted of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 3: 1. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

Example F Catalytic hydrogenation of anhydroluteins I, II, III (75% total carotenoids) with palladium on carbon (5%) in ethyl acetate at -15 ° C
To a mixture of 75% total carotenoids (0.3 g, approximately 0.225 g) and palladium on carbon (26 mg, approximately 1.3 mg Pd) (5%) in a 60 ml glass reaction tube, 20 ml of ethyl acetate is added and the mixture is Cooled to -15 ° C in a low temperature freezer. The tube was evacuated and filled with hydrogen several times and then sealed. The mixture was stirred at -15 ° C and the progress of the reaction was followed by HPLC. After nearly 24 hours, HPLC showed almost complete conversion of the anhydrolutein to the desired product. The product was warmed to ambient temperature and filtered through celite to remove the catalyst. The filtrate was concentrated under reduced pressure at a temperature below 40 ° C. and the residue was crystallized from 10 ml of a 1/1 solution of ethanol / water. Dark orange crystals were collected by filtration, washed with 5 ml of cold ethanol and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.22 g, total carotenoid yield 46%, 0.103 g) consisted of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 1: 1. HPLC also showed the presence of small amounts of unreacted anhydroluteins I and II and (3R, 3′R) -zeaxanthin.

7. Homogeneous catalytic hydrogenation of anhydroluteins I, II, III Example A Anhydrolutein I, II, III (75% total carotenoids) with palladium acetylacetonate in tetrahydrofuran (THF) at 45-50 ° C ) Catalytic hydrogenation
To a mixture of 75% total carotenoids (0.3 g, approximately 0.225 g) and palladium acetylacetonate (12 mg) in a 40 ml glass reaction tube, 10 ml of THF was added and the mixture was cooled to 0 ° C. with an ice bath. The tube was evacuated and filled with hydrogen several times and then sealed. The ice bath was removed and the mixture was stirred at 45-50 ° C. The progress of the reaction was monitored by HPLC. After nearly 15 hours, HPLC showed that no further amounts of β-cryptoxanthin and α-cryptoxanthin were formed and a significant amount of anhydrolutein remained unreacted. The product was cooled to ambient temperature and filtered through celite to remove the catalyst. The solid was washed with THF (5 ml) and the filtrate was concentrated under reduced pressure at a temperature below 40 ° C. The concentrated residue is crystallized from 10 ml of a 1/1 solution of ethanol / water. Dark orange crystals were collected by filtration, washed with 5 ml of cold ethanol and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.28 g, ˜60% total carotenoid) consisted of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 1: 1.5. HPLC also showed the presence of a small amount of (3R, 3′R) -zeaxanthin.

Example B Catalytic hydrogenation of anhydroluteins I, II, III (75% total carotenoids) with chlorotris (triphenylphosphine) rhodium (I) in ethyl acetate at ambient temperature
To a mixture of 75% total carotenoids (0.3 g, approximately 0.225 g) and (Ph ₃ P) ₃ RhCl (835 mg) in a 40 ml glass reaction tube, 15 ml of ethyl acetate was added and the mixture was cooled to 0 ° C. with an ice bath. The tube was evacuated and the solution was vented under nitrogen. The tube was then evacuated and filled with hydrogen several times and sealed. The mixture was stirred at ambient temperature and the progress of the reaction was followed by HPLC. After 2 hours, HPLC showed complete conversion of the anhydrolutein to the desired product. The product was filtered through celite to remove the catalyst and the solid was washed with ethyl acetate. At this point, the yield of total carotenoids was measured by UV-visible spectroscopy at 448 nm in hexane, using the average extinction coefficient (E1% = 2511) for α-cryptoxanthin and β-cryptoxanthin. And 96%. The filtrate was concentrated under reduced pressure at a temperature below 40 ° C. and the residue was crystallized from 10 ml of a 1/1 solution of ethanol / water. Dark orange crystals were collected by filtration, washed with 5 ml of cold ethanol and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.29 g, 74% total carotenoid purity, 0.215 g) consisted of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 5.25: 1. HPLC also showed the presence of a small amount of (3R, 3′R) -zeaxanthin.

Example C Catalytic ethyl hydride of anhydroluteins I, II, III (63% total carotenoids, 45% anhydrolutein III) with chlorotris (triphenylphosphine) rhodium (I) in ethyl acetate at ambient temperature A suspension of Wilkinson's catalyst (100 mg, 0.11 mmol) in 2 ml was purged with hydrogen and then mechanically stirred for 2 hours at room temperature under hydrogen. To the reaction mixture was added 50 mg of crude anhydrolutein (anhydrolutein III, 45%, 0.041 mmol). The mixture was stirred under hydrogen provided via a hydrogen balloon. After 2 hours, HPLC showed complete consumption of anhydrolutein. The mixture was filtered through a microfilter and the filter was washed with 2 ml of ethyl acetate. The solvent was evaporated under nitrogen and the residue was dried under high vacuum for 2 hours. The product was obtained as a red solid (90 mg) and consisted of a mixture of cryptoxanthin with a ratio of β-cryptoxanthin: α-cryptoxanthin = 5.4: 1. The yield of β-cryptoxanthin based on anhydrolutein III was 96%.

In Example D ambient temperature, [Ir (cod) Py ( Pcy 3)] + PF 6 in dichloromethane ^- catalytic hydrogenation of (Crabtree catalyst) by anhydrolutein I, II, III (75% total carotenoids)
40ml glass reaction tube anhydrolutein (75% total carotenoids, 0.3 g, approximately 0.225 g) and [Ir (cod) Py (Pcy 3)] + PF 6 - To a mixture of (10 mg), was added to dichloromethane 10 ml, The mixture was cooled to 0 ° C. with an ice bath. The tube was evacuated and the solution was vented under nitrogen. The tube was then evacuated and filled with hydrogen several times and then sealed. The mixture was stirred at ambient temperature and the progress of the reaction was followed by HPLC. After 24 hours, HPLC showed that no further amounts of β-cryptoxanthin and α-cryptoxanthin were formed and a significant amount of anhydrolutein remained unreacted. The product was filtered through celite and most of the solvent was evaporated under reduced pressure. The concentrated residue was crystallized from 10 ml of a 1/1 solution of ethanol / water. Dark orange crystals were collected by filtration and dried under high vacuum at temperatures below 40 ° C. According to HPLC, the product (0.26 g, -60% total carotenoids) is composed of a mixture of cryptoxanthin (β-cryptoxanthin: α-cryptoxanthin = 1.4: 1) and unreacted anhydrolutein (42%). It consisted of a mixture. HPLC also showed the presence of a small amount of (3R, 3′R) -zeaxanthin.

  Now that the present invention has been fully described, one of ordinary skill in the art can affect the scope of the invention or any of its embodiments within the broad and equivalent scope of conditions, formulations, and other parameters. It will be understood that the present invention can be made without effect. All patents, patent applications and publications cited herein can be fully incorporated herein by reference in their entirety.

FIG. 1 is a scheme showing the conversion of (3R, 3′R, 6′R) -lutein to β-cryptoxanthin and α-cryptoxanthin. (3R, 3'R) -zeaxanthin is present in the starting material and remains unreacted throughout the entire process. FIG. 2 is a scheme showing the conversion of lutein esters to β-cryptoxanthin and α-cryptoxanthin via anhydroluteins I-III produced by acid-catalyzed transesterification. (3R, 3'R) -zeaxanthin is present as a minor component in the starting material and is converted to non-esterified (3R, 3'R) -zeaxanthin, but the rest remains unchanged throughout the entire process .

Claims (28)

A substance composition comprising β- and α-cryptoxanthin produced using catalytic hydrogenation from a lutein-containing product selected from the group consisting of lutein, lutein esters, anhydrolutein and combinations of these lutein-containing products . 2. The composition of claim 1, wherein the lutein-containing product comprises (3R, 3'R, 6'R) -lutein. The composition according to claim 1, wherein β-cryptoxanthin is (3R) -β-cryptoxanthin and α-cryptoxanthin is (3R, 6′R) -α-cryptoxanthin. 2. A substance composition according to claim 1, wherein β- and α-cryptoxanthin comprise at least 1% by weight of the composition. A method for converting a lutein-containing product to β- and α-cryptoxanthin, wherein the lutein-containing product in alcohol is reacted with a catalytic amount of acid at elevated temperature to form a mixture of anhydrolutein; and Reacting the anhydrolutein with hydrogen in an organic solvent in the presence of a Group VIII transition element catalyst at a temperature not exceeding 100 ° C. to produce a mixture of cryptoxanthin. The lutein-containing product contains (3R, 3′R, 6′R) -lutein, β-cryptoxanthin is (3R) -β-cryptoxanthin, α-cryptoxanthin is (3R, 6′R 6. The method according to claim 5, which is) -α-cryptoxanthin. 6. The method of claim 5, wherein the temperature is between about -15 ° C and about 80 ° C. 6. The method of claim 5, wherein β- and α-cryptoxanthin comprise at least 1% by weight of the composition. A method for converting a lutein-containing product into a mixture of anhydrolutein I, II, III, wherein the lutein-containing product is selected from the group consisting of aqueous mineral acid and strong organic acids in water and one or more alcohols. Reacting with a catalytic amount of acid to be stirred at an elevated temperature to give a main product anhydrolutein III and a mixture of anhydrolutein containing minor products anhydrolutein I and II. Said method comprising. Alcohol is ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, 1-pentanol (n-amyl alcohol), 2-pentanol, n-hexyl alcohol, 10. The method of claim 9, wherein the method is selected from the group consisting of n-octyl alcohol, ethylene glycol, and propylene glycol. 10. The method of claim 9, wherein the mineral acid aqueous solution is selected from the group consisting of aqueous solutions of hydrochloric acid, sulfuric acid and phosphoric acid, and the organic acid is selected from the group consisting of trifluoroacetic acid and trichloroacetic acid. 10. A process according to claim 9, wherein the elevated temperature is the reflux temperature of the solvent. A method for converting (3R, 3'R, 6'R) -lutein ester containing (3R, 3'R) -zeaxanthin ester into a mixture of anhydrolutein, comprising hydrocarbons, ethers, and A product containing a lutein ester in a solvent selected from the group consisting of at least one alcohol is reacted with a catalytic amount of an acid selected from the group consisting of an aqueous mineral acid solution and an organic acid at a temperature below 60 ° C. Obtaining a mixture of lutein 3-acyl ester 3′-alkyl ether, adding water and additional acid, and raising the temperature between about 78 ° C. and about 100 ° C. to obtain lutein 3-acyl ester 3 Said process comprising the step of converting the '-alkyl ether to a crude mixture of anhydrolutein I, II and III rich in anhydrolutein III. 14. The method of claim 13, wherein the lutein ester containing product is selected from a crude extract of marigold flowers. Alcohol is ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, 1-pentanol (n-amyl alcohol), 2-pentanol, n-hexyl alcohol, 14. The method of claim 13, wherein the method is selected from the group consisting of n-octyl alcohol, ethylene glycol, and propylene glycol. 14. The method of claim 13, wherein the mineral acid aqueous solution is selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid. 14. The method of claim 13, further comprising hydrolyzing the lutein-containing product to remove fatty acids; and crystallizing anhydrolutein. Characterized by keeping the temperature below 50 ° C. and isolating a mixture of lutein 3-acyl ester 3′-alkyl ethers first without adding additional amounts of water and acid and without raising the temperature 14. The method of claim 13, wherein Cooling the solution containing the mixture of lutein 3-acyl ester 3′-alkyl ethers to ambient temperature; hydrolyzing the solution containing the mixture of lutein 3-acyl ester 3′-alkyl ethers with an alcohol solution of an inorganic base; 19. The method of claim 18, further comprising evaporating the solvent to obtain a concentrated residue containing lutein 3′-alkyl ether. Converting lutein 3′-alkyl ether to a mixture of anhydrolutein with a catalytic amount of an aqueous mineral acid or organic acid at a temperature between about 78 ° C. and about 100 ° C. in the presence of an alcohol or alcohol mixture. 20. The method of claim 19, further comprising: A method for converting a mixture of anhydroluteins into a mixture of β-cryptoxanthin and α-cryptoxanthin by heterogeneous catalytic hydrogenation, wherein the catalyst is selected from group VIII transition elements in an organic solvent Reacting with hydrogen in the presence of to obtain a mixture of the main product β-cryptoxanthin and a minor product α-cryptoxanthin. 24. The method of claim 21, wherein the anhydrolutein mixture is rich in anhydrolutein III. The process according to claim 21, wherein the androlutein mixture is prepared from lutein ester via lutein 3-acyl ester 3'-alkyl ether or lutein 3'-alkyl ether. The organic solvent is selected from the group consisting of ethyl acetate, acetone, tetrahydrofuran (THF), diethyl ether, diisopropyl ether and t-butyl methyl ether, dichloromethane, 1,2-dichloroethane and chloroform and combinations thereof. The method described in 1. A method for converting a mixture of anhydrolutein containing a small amount of zeaxanthin to β-cryptoxanthin and α-cryptoxanthin by homogeneous catalytic hydrogenation, selected from transition metal complexes in organic solvents Reacting anhydrolutein with hydrogen in the presence of a catalyst at a temperature of less than about 60 ° C. to obtain a mixture of β-cryptoxanthin and α-cryptoxanthin. Transition metal complexes include palladium acetylacetonate, tris (triphenylphosphine) rhodium (I) chloride [Rh (Ph ₃ P) ₃ Cl] (Wilkinson catalyst), (tricyclohexylphosphine) (1,5-cyclooctadiene) Pyridine iridium (I) hexafluorophosphate [(C ₆ H ₁₁ ) ₃ P [C ₈ H ₁₂ ] [C ₅ H ₅ N]] Ir ⁺ PF ₆ ⁻ (Crabtree catalyst) and (1,5-cyclooctadiene) ) bis (methyl diphenyl phosphine) iridium (I) hexafluorophosphate _{[C 8 H 12] [(} MePh 2 P) 2] Ir + PF 6 - is selected from the group consisting of the method of claim 25. 26. Process according to claim 25, characterized in that the mixture of anhydroluteins I to III is enriched in anhydrolutein III. The organic solvent is selected from the group consisting of ethyl acetate, acetone, tetrahydrofuran (THF), diethyl ether, diisopropyl ether and t-butyl methyl ether, dichloromethane, 1,2-dichloroethane and chloroform and combinations thereof. The method described in 1.

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