- A PRACTICAL SYNTHESIS OF MYRCENOL BY PALLADIUM COMPLEX-CATALYZED ELIMINATION REACTION
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A Palladium complex-catalyzed elimination reaction of allyl amines was studied to establish a practical process for production of myrcenol.The catalytic elimination occurred smoothly with the cationic Pd(II) complexes.Among a variety phosphorous ligands, the tetramethylene and the pentamethylene diphosphine ligands proved to be the best ligand with respects to the catalytic activity and selectivity.
- Kumobayashi, Hidenori,Mitsuhashi, Shigeru,Akutagawa, Susumu,Ohtsuka, Sei
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p. 157 - 160
(2007/10/02)
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- Etude des phenomenes physico-chimiques intervenant lors du procede d'hydrodistillation
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During the steam distillation of aromatic plants, some terpenic compounds undergo various chemical reactions (hydrolysis, elimination, cyclisation rearrangement) which depend on the acidity of the water in which the plant is soaked.In order to study the physical and chemical phenomena involved in this process and in particular the formation of artefacts, we have performed steam distillation experiments on lavender flowers in a buffered aqueous medium.The essential oils collected are rich in linalol and linalyl acetate, two monoterpenic compounds known for their propensity to undergo heat induced transformations.At pH 4 or 7, the chromatograms of the essential oils are similar whereas in a more acidic medium (pH = 2), the degradation of linalyl acetate gives rise to a number of terpenic products (α and γ terpinenes; 2,6,6-trimethyl 2-vinyl tetrahydropyran; 1,4-cineol, cis and trans ocimenols, myrcenol, terpin 1-en 4-ol, etc.).A study of the reactions involved during the thermal degradation of linalyl acetate in a model experiment (heating to reflux) as well as the determination of the kinetic parameters, show that some terpenes, present in lavender oil originate in part from the transformations of linalyl acetate during steam distillation.Furthermore, the decomposition of this ester is directly and quantitatively related to the concentration of acid in the medium (pseudo first order rate constant is 0.008 min-1 at pH 7 and 0.0147 min-1 at pH 2).It is therefore necessary to control and maintain the pH of the water during steam distillation to avoid the alteration of the essential oils by formation of artefacts and preserve the integrity of the oil originally present in the plant.The study of the various steam distillation fractions gives informaiton on the kinetics of the steam distillation of the various components which apparently do not depend only on the boiling point but also on their polarity (hydrodiffusion phenomenon).
- Morin, Ph.,Gunther, C.,Peyron, L.,Richard, H.
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p. 921 - 930
(2007/10/02)
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- Process for preparing a myrcenol, cis-ocimenol mixture substantially free of trans-ocimenol
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The instant invention provides a new and improved method of preparing the Diels Alder mixture of 3 and 4-(4-methyl-4-hydroxyamyl)Δ3 -cyclohexenecarboxaldehyde from the readily available myrcene. The novel sequence includes a synthesis of a novel myrcenol, ocimenol intermediate which is substantially free of trans-ocimenol.
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