- Limonene oxyfunctionalization over Cu-modified silicates employing hydrogen peroxide and t-Butyl hydroperoxide: Reaction pathway analysis
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Limonene oxidation over Cu-nanostructured mesoporous materials was studied. Three solids with different copper content were synthesized employing the template-ion exchange method, and physically-chemically analyzed by a multi-technical characterization. The performance of the molecular sieves as catalysts in the liquid phase oxyfunctionalization of limonene, employing hydrogen peroxide (H2O2) or t-butyl hydroperoxide (TBHP) as oxidants was evaluated. All synthesized Cu-MCM materials were active in the reaction. The obtained results showed that the used oxidant had an important influence on the products distribution under the employed conditions. With H2O2, compounds of high added value such as limonene oxide, carveol and carvone were mainly obtained. Meanwhile, with TBHP, limonene hydroperoxide turned out to be the major product. Finally, a reaction mechanism was proposed for each oxidant.
- Vaschetti, Virginia M.,Cánepa, Analía L.,Barrera, Deicy,Sapag, Karim,Eimer, Griselda A.,Casuscelli, Sandra G.
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- Oxidation reactions in segmented and continuous flow chemical processing using an N -(tert -Butyl)phenylsulfinimidoyl chloride monolith
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A supported version of N-(tert-butyl)phenylsulfinim-idoyl chloride on a monolithic material is described, which can be incorporated into a flow chemical processing arrangement to oxidise a variety of substrates in both stoichiometric and catalytic processes to yield products in high yields and in high purity after in-line workup. Georg Thieme Verlag Stuttgart.
- Lange, Heiko,Capener, Matthew J.,Jones, Alexander X.,Smith, Catherine J.,Nikbin, Nikzad,Baxendale, Ian R.,Ley, Steven V.
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experimental part
p. 869 - 873
(2011/06/21)
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- A chemoenzymatic, preparative synthesis of the isomeric forms of p-menth-1-en-9-ol: Application to the synthesis of the isomeric forms of the cooling agent 1-hydroxy-2,9-cineole
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A preparative-scale synthesis of the four p-menth-1-en-9-ol isomers 2a-5a has been achieved by means of two chemoenzymatic processes. Both synthetic pathways start from the enantiomeric forms of limonene that are converted into p-mentha-1,8-dien-9-al isomers 12 and 15. The baker's yeast mediated reduction of the latter aldehydes afforded compounds 3a and 5a, respectively, with very high enantioselectivity. Moreover, chemical reduction of 12 and 15 gives the mixtures of enantiopure diastereoisomers 2a/3a and 4a/5a, respectively. PPL (Porcine pancreas lipase) mediated resolution of the latter mixtures followed by fractionating crystallization of derivatives 2b-5b allowed the enantio- and diastereoisomerically pure alcohols 2a-5a to be obtained. Compounds 2a-5a have then been used as starting materials for the preparation of four isomers of the cooling agent 1-hydroxy-2,9-cineole (6-9). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Serra, Stefano,Fuganti, Claudio,Gatti, Francesco G.
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experimental part
p. 1031 - 1037
(2009/04/05)
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- Synthetic scope of alcohol transfer dehydrogenation catalyzed by Cu/Al 2O3: A new metallic catalyst with unusual selectivity
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A method for the anaerobic oxidation of a wide series of alcohols including cyclohexanols and steroidal alcohols, has been set up. It relies on a transfer dehydrogenation reaction from the substrate alcohol to styrene catalyzed by a heterogeneous, reusable copper catalyst under very mild liquid phase experimental conditions (90°C, N2) and shows unusual selectivity. Thus, the method is selective for the oxidation of secondary and allylic alcohols even in the presence of unprotected primary and benzylic alcohols. Electronic effects and the choice of the hydrogen acceptor account for the selectivity observed.
- Zaccheria, Federica,Ravasio, Nicoletta,Psaro, Rinaldo,Fusi, Achille
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p. 6426 - 6431
(2008/09/20)
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- Stereochemical aspects of the bioreduction of the conjugated double bond of perillaldehyde
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A study on the regioselective reduction of the conjugate double bond of perillaldehyde is described. The chemical reduction of this substrate was investigated in order to provide a straightforward access to the relevant natural flavour, dihydroperillaldehyde. The biological reduction of both natural (S)-(-)-perillaldehyde and synthetic (R)-(+)-perillaldehyde was accomplished by means of fermenting baker's yeast. The latter microorganism converted, with different diastereoselectivity, the (S)- and (R)-enantiomers into the corresponding trans and cis saturated alcohols, respectively. The origin of the hydrogen atoms added to the double bond was studied by deuterium labelling experiments and 2H NMR measurements that clearly demonstrate a different mechanism of the biohydrogenation of the two enantiomeric forms of perillaldehyde.
- Fronza, Giovanni,Fuganti, Claudio,Pinciroli, Matteo,Serra, Stefano
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p. 3073 - 3077
(2007/10/03)
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- TEMPO-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes and Ketones in Ionic Liquid [bmim][PF6]
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(matrix presented) A simple and mild TEMPO-CuCl catalyzed aerobic oxidation of primary and secondary alcohols to the corresoponding aldehydes and ketones in ionic liquid [bmim][PF6] with no trace of overoxidation to carboxylic acids has been developed. The product can be isolated by a simple extraction with organic solvent, and the ionic liquid can be recycled or reused.
- Ansari, Imtiaz A.,Gree, Rene
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p. 1507 - 1509
(2007/10/03)
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- Inhibition of protein prenylation by metabolites of limonene
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The monoterpenes limonene and perillyl alcohol are undergoing clinical evaluation in cancer patients. In this paper, we report the chemical synthesis, characterisation, and quantitation in patients' plasma of a novel human metabolite of limonene, which is
- Hardcastle, Ian R.,Rowlands, Martin G.,Moreno Barber, Amelia,Grimshaw, Rachel M.,Mohan, Mukesh K.,Nutley, Bernard P.,Jarman, Michael
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p. 801 - 809
(2008/04/18)
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- Novel limonene phosphonate and farnesyl diphosphate analogues: Design, synthesis, and evaluation as potential protein-farnesyl transferase inhibitors
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Limonene and its metabolite perillyl alcohol are naturally-occurring isoprenoids that block the growth of cancer cells both in vitro and in vivo. This cytostatic effect appears to be due, at least in part, to the fact that these compounds are weak yet sel
- Eummer, Jeffrey T.,Gibbs, Barbara S.,Zahn, Todd J.,Sebolt-Leopold, Judith S.,Gibbs, Richard A.
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p. 241 - 250
(2007/10/03)
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- The oxidation of allylic methylene groups under FeIII-TBHP and FeIII-TBHP-PA conditions
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Oxidation of allylic methylene groups under FeIII-TBHP (FeIII-t-butyl hydroperoxide) and FeIII-TBHP-PA (FeIII-t-butyl hydroperoxide-picolinic acid) conditions gave α- and γ-ketonization products.
- Barton, Derek H. R.,Wang, Tie-Lin
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p. 4307 - 4310
(2007/10/02)
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- Enantioselective synthesis of chiral liquid crystalline compounds from monoterpenes
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Chiral liquid crystalline compounds 1-9 have been synthesized enantioselectively from monoterpenes. The optical purities of (S)-(-)- and (R)-(+)-perillalcohol (16, 27), (S)-(-)- and (R)-(+)-1-pentyl-4-hydroxymethyl-1-cyclohexene (33, 34) and (2S,5S)-2-pentyl-5-hydroxymethyl-1-cyclohexanone (53) have been determined by 1H NMR analysis using chiral shift reagents. The mesomorphic phases and transition temperatures of compounds 2,3,5,6,7,8 and 9 have been characterized.
- Wang, Qian,Fan, Shi Yan,Wong, Henry N. C.,Li, Zhong,Fung, Bing M.,Twieg, Robert J.,Nguyen, Huu Tinh
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p. 619 - 638
(2007/10/02)
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- FUNCTIONALISATION OF SATURATED HYDROCARBONS. PART XVII. REACTIVITY OF CARBON-CARBON DOUBLE BONDS.
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The Gif oxidation systems cleave methylidene olefins into the ketone or aldehyde and formaldehyde.This is considered to be a further manifestation of an Fe oxenoid species.Similarly, more substituted olefins are oxidized to the corresponding unsaturated ketones or aldehydes.The oxidation of limonene afforded the ketone 24 resulting from methylene cleavage and racemic carvone 25.The latter is considered to originate from a symmetrical ?-allyl complex of iron.
- Barton, Derek H. R.,Lee, Kyu Wan,Mehl, Wolf,Ozbalik, Nubar,Zhang, Li
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p. 3753 - 3768
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF (R)-(+)-PERILLALDEHYDE
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A short and efficient synthesis of the commercially unavailable (R)-(+) isomer of perillaldehyde from (+)-limonene oxide has been developed.
- Tius, Marcus A.,Kerr, Michael A.
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p. 1905 - 1912
(2007/10/02)
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