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- OHRNER, N, et al.
(författare)
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THIOETHYL-OCTANOATE, VINYL-OCTANOATE, ETHYL-OCTANOATE ESTERS AND OCTANOIC-ACID AS ACYL DONORS IN LIPASE-CATALYZED ACYL TRANSFER-REACTIONS
- 1994
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Ingår i: BIOCATALYSIS. - ROYAL INST TECHNOL,DEPT ORGAN CHEM,S-10044 STOCKHOLM 70,SWEDEN. : HARWOOD ACAD PUBL GMBH. - 0886-4454. ; 9:1-4, s. 105-114
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Tidskriftsartikel (refereegranskat)abstract
- S-Ethyl thiooctanoate, vinyl octanoate, ethyl octanoate and octanoic acid were studied as acyl donors in a lipase catalysed acyl transfer reaction with 2-octanol as acyl acceptor. The reaction conditions had a pronounced effect on the equilibrium displacement and the apparent enantioselectivity. The thioethyl and vinyl esters proved to be efficient acyl donors under atmospheric pressure and 39-degrees-C, affording a high apparent enantiomeric ratio. Under these reaction conditions the apparent enantioselectivity seemed to be enhanced by water, which was present in the reaction system and caused the production of octanoic acid, by hydrolysis of the acyl enzyme.
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- Unelius, C. Rikard, Professor, 1958-, et al.
(författare)
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A Short Synthesis of Gastrolactone
- 1994
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Ingår i: Natural product letters (Print). - : Informa UK Limited. - 1057-5634 .- 1029-2349. ; 5:1, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Gastrolactone, a component from the larval defensive secretion of the chrysomelid beetle Gastrophysa cyanea, was synthesized in four steps from citral. The key step was an enal-enamine [2+4] cycloaddition. Gastrolactol, the lactol form of plagiodial, was an intermediate in the synthetic sequence. © 1994, Taylor & Francis Group, LLC. All rights reserved.
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| 5. |
- Valterova, I., et al.
(författare)
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Enantiomeric Composition of Monoterpene Hydrocarbons from the Liverwort Conocephalum-Conicum
- 1992
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Ingår i: Phytochemistry. - 0031-9422 .- 1873-3700. ; 31:9, s. 3121-3123
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Tidskriftsartikel (refereegranskat)abstract
- Volatiles from the essential oil of the liverwort Conocephalum conicum were analysed. The chirality of the monoterpene hydrocarbons was studied by two-dimensional ps chromatography. All compounds except beta-phellandrene showed high optical purity. For the identification of enantiomers, (+)-beta-phellandrene and (-)-alpha-thujene were prepared from (+)-limonene and (+)-sabinene, respectively.
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- Öhrner, Niklas, et al.
(författare)
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Displacement of the equilibrium in lipase catalysed transesterification in ethyl octanoate by continous evaporation of ethanol
- 1992
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Ingår i: Biotechnology letters. - : CHAPMAN HALL LTD. - 0141-5492 .- 1573-6776. ; 14:4, s. 263-268
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Tidskriftsartikel (refereegranskat)abstract
- A simple method to overcome low equilibrium conversion in lipase catalysed resolution of alcohols by transesterification was developed. Ethyl octanoate was used as acyl donor as well as solvent and the reaction equilibrium was shifted by applying reduced pressure, forcing the co-product ethanol to evaporate during the reaction. Using a lipase from Candida antarctica 2-octanol, 1-phenyl ethanol, 1-cyclohexyl ethanol and trans-2-methylcyclohexanol were resolved in good optical and chemical yields.
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