210. Dehydrogenation. Part IV. Catalytic disproportionation and dehydrogenation of some terpenes and terpene ketones

Linstead, R. P.; Michaelis, K.; Thomas, Siji

doi:10.1039/jr9400001139

Cited by 39 publications

(16 citation statements)

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“…We have been interested in the development of an environmentally friendly process for isomerization of carvone to carvacol. This reaction has been observed since 1940 with the use of group VIII metals as the catalyst [3][4][5][6][7]. These methods involved either the metal or complexes of palladium, nickel, iridium, rhodium or ruthenium.…”

Section: Introductionmentioning

confidence: 94%

Heterogeneous acid-catalysed isomerization of carvone to carvacrol

Gozzi

Convard

Husset

2009

React Kinet Catal Lett

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Section: Introductionmentioning

confidence: 94%

Heterogeneous acid-catalysed isomerization of carvone to carvacrol

Gozzi

Convard

Husset

2009

React Kinet Catal Lett

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“…Since the thujones have been isomerized to carvotanacetone a t 280' C (23) it is likely that this rearrangement has occurred during distillation even though the pot temperature did not exceed 160" C. Disproportionation of carvone to carvacrol arid more saturated ketones, including carvotanacetone (24,25), may also have taken place. The fact that the compound isolated from the distilled fraction was optically inactive lends strong support that rearrangement from isothujone to carvotanacetone has occurred preferentially.…”

Section: Results a S D Discussionmentioning

confidence: 99%

Gas–liquid Chromatography of Terpenes: Part Viii. The Volatile Oil of Tanacetum Vulgare L.

Rudloff¹

1963

Can. J. Chem.

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The chemical composition of the commercial oil of tansy and of that obtained from a local tansy species s a s determined by means of gas-liquid chromatography. Both oils contained d-isothujone as the major component (68.57,,, 587"). The commercial oil contained fairly large alnounts of I-camphor (13.9%), whereas that froin local plants had only traces of camphor and 19.87" of I-thujone. The minor components isolated and identified in both oils were I-a-pinene, 1-camphene, d-sabinene, d-limonene, 1 : 8-cineole, yterpinene, P-cymene, d-terpinen-4-01, 1-carvotanacetone, and 1-borneol. Small amounts of a-thujene, p-pinene, a-terpinene, terpinolene, neoisothujyl and isothujyl alcohols, and dihydrocarvone were identified by retention characteristics only. Car-4-ene, isomeric alloocitnenes, and carvomenthone may also be present. An unknown, crystalline monoterpene alcohol with a terminal methylene group was isolated in sinall amounts. A sesquiterpene (3.'i7,,) was obtained from the oil of local plants.Prefractionation of these oils by fractional distillation resulted in extensive isomerization of isothujone to dl-carvotanacetone. Such a rearrangement was not encountered during prefractionation by preparative gas-liquid chromatography.

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“…[28] Dieses Beispiel ist instruktiv,u md en Wert von Konjugation und in diesem Fall Aromatizitäta ls mutmaßliche Triebkraft hervorzuheben, die Direktionalitätg ewährleistet. Ein relevantes Beispiel ist die direkte Synthese von Carvacrol aus Carvon unter Säurekatalyse über die Bildung eines tertiären Carbokation-Intermediats.…”

Section: Positionelle Isomerisierung I: Thermodynamisch Gesteuerte Alunclassified

“…Ein relevantes Beispiel ist die direkte Synthese von Carvacrol aus Carvon unter Säurekatalyse über die Bildung eines tertiären Carbokation-Intermediats. [28] Dieses Beispiel ist instruktiv,u md en Wert von Konjugation und in diesem Fall Aromatizitäta ls mutmaßliche Triebkraft hervorzuheben, die Direktionalitätg ewährleistet. Die positionelle Isomerisierung von Butenen bringt diese Neigung zur Entstehung des stabileren, internen Alkenisomers weiter zum Ausdruck, in diesem Fall beschleunigt durch die homolytische Spaltung von Iod in der Gasphase zur Bildung eines Radikalintermediats.…”

Section: Positionelle Isomerisierung I: Thermodynamisch Gesteuerte Alunclassified

Positionelle und geometrische Isomerisierung von Alkenen: der Gipfel der Atomökonomie

2019

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Strategien zur raumzeitlichen Steuerung von Alkenen durch einen äußeren Reiz sind angesichts der Allgegenwart von Rohstoff‐Olefinen in der Chemie und ihren Folgeanwendungen notwendig. Angelehnt an den 1‐0‐Schalter, der den Sehzyklus von Säugetieren durch eine selektive geometrische Isomerisierung von Retinal ermöglicht, werden Strategien zur geometrischen und positionellen Manipulation des zweidimensionalen Raums von Alkenen mittels chemischer, thermischer und lichtinduzierter Prozesse intensiv untersucht. Dieser Kurzaufsatz beleuchtet den aktuellen Stand der Forschung zur Aktivierung und dem Ermöglichen von Direktionalität in diesen fundamentalen chemischen Transformationen.

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210. Dehydrogenation. Part IV. Catalytic disproportionation and dehydrogenation of some terpenes and terpene ketones

Cited by 39 publications

References 0 publications

Heterogeneous acid-catalysed isomerization of carvone to carvacrol

Heterogeneous acid-catalysed isomerization of carvone to carvacrol

Gas–liquid Chromatography of Terpenes: Part Viii. The Volatile Oil of Tanacetum Vulgare L.

Positionelle und geometrische Isomerisierung von Alkenen: der Gipfel der Atomökonomie

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