- Chemo-Enzymatic Oxidative Rearrangement of Tertiary Allylic Alcohols: Synthetic Application and Integration into a Cascade Process
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A chemo-enzymatic catalytic system, comprised of Bobbitt's salt and laccase from Trametes versicolor, allowed the [1,3]-oxidative rearrangement of endocyclic allylic tertiary alcohols into the corresponding enones under an Oxygen atmosphere in aqueous media. The yields were in most cases quantitative, especially for the cyclopent-2-en-1-ol or the cyclohex-2-en-1-ol substrates without an electron withdrawing group (EWG) on the side chain. Transpositions of macrocyclic alkenols or tertiary alcohols bearing an EWG on the side chain were instead carried out in acetonitrile by using an immobilized laccase preparation. Dehydro-Jasmone, dehydro-Hedione, dehydro-Muscone and other fragrance precursors were directly prepared with this procedure, while a synthetic route was developed to easily transform a cyclopentenone derivative into trans-Magnolione and dehydro-Magnolione. The rearrangement of exocyclic allylic alcohols was tested as well, and a dynamic kinetic resolution was observed: α,β-unsaturated ketones with (E)-configuration and a high diastereomeric excess were synthesized. Finally, the 2,2,6,6-tetramethyl-1-piperidinium tetrafluoroborate (TEMPO+BF4?)/laccase catalysed oxidative rearrangement was combined with the ene-reductase/alcohol dehydrogenase cascade process in a one-pot three-step synthesis of cis or trans 3-methylcyclohexan-1-ol, in both cases with a high optical purity. (Figure presented.).
- Brenna, Elisabetta,Crotti, Michele,De Pieri, Matteo,Gatti, Francesco G.,Manenti, Gabriele,Monti, Daniela
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supporting information
p. 3677 - 3686
(2018/06/04)
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- PROCESS FOR THE MANUFACTURE OF 3,7-DIMETHYL-1-OCTEN-3-OL
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The present invention is directed to a process for the manufacture of 3,7-dimethyl-1-octen-3-ol comprising the following steps: a) hydrogenation of 6-methyl-5-hepten-2-on to 6-methyl-2-heptanon in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of carbon, calcium carbonate and aluminum oxide.b) reaction of 6-methyl-2-heptanon with acetylene to 3,7-dimethyl-1-octin-3-ol in the presence of ammonia and potassium hydroxide and in the absence of any additional organic solvent;c) hydrogenation of 3,7-dimethyl-1-octin-3-ol to 3,7-dimethyl-1-octen-3-ol in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of calcium carbonate, aluminum oxide, silica, porous glass, carbon or graphite, and barium sulphate, with the proviso that the catalyst additionally contains lead when the carrier is calcium carbonate. The present invention is further directed to a process for the manufacture of isophytol and vitamin E, where a thus produced 3,7-dimethyl-1-octen-3-ol is used as starting material.
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Page/Page column 5
(2012/03/12)
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- Preparation of C10-C30-alkenes by partial hydrogenation of alkynes over fixed-bed supported palladium catalysts
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Alkenes are prepared by partial hydrogenation of alkynes in the liquid phase at from 20 to 250° C. and hydrogen partial pressures of from 0.3 to 200 bar over fixed-bed supported palladium catalysts which are obtainable by heating the support material in the air, cooling, applying a palladium compound and, if required, additionally other metal ions for doping purposes, molding and processing to give monolithic catalyst elements, by a process in whichA) alkynes of 10 to 30 carbon atoms are used as starting compounds,B) the palladium compound and, if required, the other metal ions are applied to the support material by impregnation of the heated and cooled support material with a solution containing palladium salts and, if required, other metal ions and subsequent drying, andC) from 10 to 2000 ppm of carbon monoxide (CO) are added to the hydrogenation gas or a corresponding amount of CO is allowed to form in the liquid phase by slight decomposition of a compound which is added to the reaction mixture and eliminates CO under the reaction conditions.The process is particularly advantageous if the partial hydrogenation is carried out in a tube reactor by the trickle-bed or liquid phase procedure with product recycling at cross-sectional loadings of from 20 to 500 m3/m2*h. The process is particularly suitable for the preparation of 3,7,11,15-tetramethyl-1-hexadecen-3-ol (isophytol), 3,7,11-trimethyl-l-dodecen-3-ol (tetrahydronerolidol), 3,7,11-trimethyl-1,4-dodecadien-3-ol, 3,7,11-trimethyl-1,6-dodecadien-3-ol (dihydronerolidol), 3,7-dimethyloct-1,6-dien-3-ol or 3,7-dimethyloct-1-en-3-ol from the corresponding alkynes.
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- Process for producing 6-methyl-3-hepten-2-one and 6-methyl-2-heptanone analogues, and process for producing phyton or isophytol
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Provided are a process for producing 6-methyl-3-hepten-2-one by cross aldol condensation carried out while each continuously adding to acetone, isovaleraldehyde and an aqueous alkali containing an alkaline substance; a process for producing a 6-methyl-2-heptanone analogue represented by Formula (1): STR1 wherein n is an integer of 0 or 1 or more; which comprises allowing hydrogen, acetone and an aldehyde represented by Formula (2): STR2 wherein n is as defined above; X and Y each represents a hydrogen atom or they are coupled together to form a carbon-carbon bond; and Z and W each represents a hydrogen atom or they are coupled together to form a carbon-carbon bond; to react in the presence of an aqueous alkali containing an alkaline substance, and a hydrogenation catalyst; and a process for producing phyton or isophytol using the 6-methyl -3-hepten-2-one or the 6-methyl-2-heptanone analogue.
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- Process for the preparation of tocopherol derivatives and catalyst
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A process is provided for the preparation of an α-tocopherol derivatives which are useful as antisterile vitamins, hypolipidemics, blood flow increasing agents, anti-cytosenility agents, antioxidants and the like. Catalysts are also provided. The α-tocopherol derivatives are represented by the following formula (VII): STR1 wherein n stands for 0 or an integer of from 1 to 5. The derivatives can be industrially prepared by employing as catalyst a metal ion-exchanged montmorillonite, metal ion-exchanged bentonite or metal ion-exchanged saponite which is substituted with one metal ion selected from the group consisting of scandium, yttrium, lanthanide element, aluminium, iron, tin, copper, titanium, zinc, nickel, gallium or zirconium.
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- Synthesis of vitamin E analogues: Possible active forms of vitamin E
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We synthesized several vitamin E analogues containing oxygenated functional groups in place of the 8-methyl group which is common to all the natural vitamin E congeners, based on the hypothesis that the methyl group might be metabolically oxidized to produce active forms which might have specific functions other than the antioxidant function. All the vitamin E analogues examined had antioxidant activity. 8-[6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman]meth anol (1d) and 2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-6-ol (4d) showed similar activity to α-tocopherol. 6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman-8-carba ldehyde (2d) and 6-hydroxy-2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-8-carb oxylic acid (3d) showed weaker activity than α-tocopherol, but their duration of action, especially that of 3d was considerably longer.
- Fujishima, Toshie,Kagechika, Hiroyuki,Shudo, Koichi
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