92760-19-5Relevant academic research and scientific papers
Process For The Preparation of Beta and Alpha Cryptoxanthin
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Page/Page column 10, (2010/12/29)
The present invention relates to a process for converting lutein and/or lutein esters to (3R)-β-cryptoxanthin and (3R,6′R)-α-cryptoxanthin, suitable for human consumption as dietary supplements, by employing safe and environmentally friendly reagents. (3R)-β-Cryptoxanthin and (3R,6′R)-α-cryptoxanthin are two rare food carotenoids that are not commercially available and the former exhibits vitamin A activity. In the first synthetic step, commercially available lutein and/or lutein esters are transformed into a mixture of dehydration products of lutein (anhydroluteins) in the presence of a catalytic amount of an acid. The resulting anhydroluteins are then converted to (3R)-β-cryptoxanthin (major product) and (3R,6′R)-α-cryptoxanthin (minor product) by heterogeneous catalytic hydrogenation employing transition elements of group VIII (Pt, Pd, Rh supported on alumina or carbon) in a variety of organic solvents under atmospheric pressure of hydrogen and at temperatures ranging from ?15° C. to 40° C. Among these catalysts, Pt supported on alumina at 40° C. in ethyl acetate provides the best yield of (3R)-β-cryptoxanthin and (3R,6′R)-α-cryptoxanthin. Several homogeneous catalysts can also promote the regioselective hydrogenation of anhydroluteins to a mixture of (3R)-β-cryptoxanthin and (3R,6′R)-α-cryptoxanthin in low to moderate yields. The catalysts may be transition metal complexes such as palladium acetylacetonate, Rh(Ph3P)3Cl (Wilkinson's catalyst), [(C6H11)3P[C8H12][C5H5N] Ir+PF6? (Crabtree catalyst), or [C8H12][(MePh2P)2]Ir+PF6?. Among these, Wilkinson catalyst converts anhydroluteins to (3R)-β-cryptoxanthin and (3R,6′R)-α-cryptoxanthin in nearly quantitative yield. A novel feature of this invention is the regioselective hydrogenation of anhydroluteins while the highly conjugated polyene chain of these carotenoids remains intact.
PROCESS FOR THE PREPARATION OF ALPHA- AND BETA-CRYPTOXANTHIN
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Page/Page column 11-13; 25-26, (2008/06/13)
The present invention relates to a process for converting lutein and/or lutein esters to β-cryptoxanthin and α-cryptoxanthin, suitable for human consumption as dietary supplements, by employing safe and environmentally friendly reagents. In the first synthetic step, commercially available lutein and/or lutein esters are transformed into a mixture of dehydration products of lutein (anhydroluteins) in the presence of a catalytic amount of an acid. The resulting anhydroluteins are then converted to β-cryptoxanthin (major product) and α-cryptoxanthin (minor product) by heterogeneous catalytic hydrogenation employing transition elements of group VIII in a variety of organic solvents under atmospheric pressure of hydrogen. A novel feature of this invention is the regioselective hydrogenation of anhydroluteins while the highly conjugated polyene chain of these carotenoids remains intact.
Method for production of rare carotenoids from commercially available lutein
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Page/Page column 16, (2008/06/13)
Disclosed are processes for conversion of (3R,3′R,6′R)-lutein to (3R,6′R)-α-cryptoxanthin, (3R)-β-cryptoxanthin, anhydroluteins I, II, and III (dehydration products of lutein), and a method for separating and purifying the individual carotenoids including the unreacted (3R,3′R)-zeaxanthin. The invention also includes two methods that transform (3R,3′R,6′R)-lutein into (3R,6′R)-α-cryptoxanthin in excellent yields.
Separation and identification of carotenoids and their oxidation products in the extracts of human plasma
Khachik, Frederick
, p. 2111 - 2122 (2007/10/02)
Eighteen carotenoids as well as vitamin A and two forms of vitamin E (γ- and α-tocopherol) have been separated from extracts of human plasma by high-performance liquid chromatography (HPLC) on reversed-phase and silica-based nitrile-bonded columns. In the order of chromatographic elution on a C18 reversed-phase column, the carotenoids were identified as (3R,3′R,6′R)-β,ε-carotene-3,3′-dlol [(3R,3′R,6′R)-lutein], (3R,3′R)-β,β-carotene-3,3′-dlol [(3R,3′R)-zeaxanthin], 5,6-dihydroxy-5,6-dihydro-ψ,ψ-carotene,3-hydroxy-2′,3′- didehy-dro-β,ε-carotene,β,ε-caroten-3-ol,3-hydroxy-β- carotene,ψ,ψ-carotene, 7,8-dihydro-ψ,ψ-carotene, β,ψ-carotene, 7,8,7′,8′-tetrahydro-′,′-carotene, β,ε-carotene, β,β-carotene, 7,8,11,12,7′,8′-hexahydro-ψ,ψ-carotene, and 7,8,11,12,7′,8′,-11′,12′-octahydro-ψ,ψ-carotene. The polar carotenoids, which eluted in the vicinity of lutein and were unresolved on the C18 column, have been separated on a nitrile-bonded column employing isocratic HPLC conditions. In the order of elution, the carotenoids were ε,ε-carotene-3,3′-dione, 3′-hydroxy-ε,ε-caroten-3-one, 5,6-dihydroxy-5,6-dihydro-ψ,ψ-carotene, 3-hydroxy-β,ε-caroten-3′-one, (all-E,3r,3′R,6′R)-lutein, (all-E,3R,3′R)-zeaxanthin, and (all-E,3R,3′S,6′R)-β,ε-carotene-3,3′-diol (3′-epilutein) followed by several geometrical isomers of lutein and zeaxanthin.
