Paper Chromatography of the Tropolones of Cupressaceae II

Zavarin, Eugene; Anderson, Arthur B.

doi:10.1021/jo01091a040

Cited by 31 publications

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“…Nozoe [9,10] first studied tropolone derivatives in Thujopsis dolabrata. Zavarin and Anderson [11] and Zavarin et al [12,13,14] also studied tropolones in the family Cupressaceae; and there is a series of studies on chemicals in Juniperus thurifera [15]. Conifer Cupressaceous trees contain many different types of tropolone derivatives, including thujaplicins ( -, -, -isoforms), -thujaplicinol, -dolabrin, -dolabrinol, nootkatin, nootkatinol, pygmaein, isopygmaein, procein, chanootin, hydroxy alkenyl tropolone, as well as nezukone (4-isopropyltropone) in the heartwood [12,14,16,17], as shown in ( Fig.…”

Section: Chemistry Of Plant Troponoidsmentioning

confidence: 96%

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Zhao

2007

CMC

107

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Tropone or tropolone and its derivatives (here together called troponoids) belong to a family of natural products with a seven-membered aromatic ring and various side groups. They are mainly synthesized by plants and fungi, and most troponoids play roles of antibacterial defenses in these organisms. With an increasingly severe situation of antibiotic resistant bacteria, as well as a requirement for antifungal medicines, troponoids have attracted extensive studies since they have powerful antibacterial and antifungal activity, particularly against antibiotic-resistant bacteria. In addition, many other biological activities such as antiviral, antitumor, antioxidant, anti-inflammatory, insecticidal, or enzyme inhibitor activities are associated with troponoids. After extensive studies in the 1960s-70s, interests in natural troponoids dedclined. However, chemical and biomedical studies on troponoids bloom again from the 1990s. To date great progress has been made with troponoid study in terms of identification of new natural troponoids, chemical synthesis and properties, biological activity, biosynthesis and metabolism. Particularly, bioassay-guided screening strategy and structure-activity relation-directed structure modification and drug design has resulted in the synthesis and discovery of many new derivatives. Many of them have great promise to be developed into new medicines for their potent and specific activities. This review presents the recent advances in troponoid studies and highlights multiple faceted biological activities of troponoids, as well as their relationships with chemical structures. Chemistry, biosynthesis, and production via biotechnology of troponoids are also briefly reviewed. Applications of troponoids in daily life, agriculture, medicine, and industry, and the related patents have been considered to further extend our understanding of the increasing impact of troponoids on humans.

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Section: Chemistry Of Plant Troponoidsmentioning

confidence: 96%

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Zhao

2007

CMC

107

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“…), and other species of the family Cupressaceae. [19,20] We therefore treated the methoxytropones 20aϪc and 20e with HBr/ acetic acid, and obtained the 7-hydroxytropolones 29aϪd in very good yields (Ͼ 94%) ( Table 4). Banwell's synthesis [18] used expensive organostannanes and palladium catalysts, but our methodology avoids this.…”

Section: Demethylation Of the Methoxytroponesmentioning

confidence: 99%

A Novel Synthesis of 2‐Alkoxy‐3‐hydroxytropones and 2,7‐Dihydroxytropones from Dialkoxy‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐ones

2004

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Trichloro‐substituted 8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐ones 6 and 7 are solvolysed by methanolic sodium methoxide to form the bicyclo[3.2.1] α,α‐dimethoxy ketones 13 and 14, with preservation of one chloro substituent. In the case of 6a, prolonged reaction time with an excess of methanolic sodium methoxide provides a trimethoxy‐substituted oxanorbornene aldehyde 19 through ring contraction. Treatment of the mixture of 13 and 14 with zinc and aqueous acetic acid affords dechlorinated α‐oxo acetals 15 and 16. Starting with the [4+3] cycloadducts derived from 2‐methylfuran and tetrachloroacetones (6b and 7b), the same procedure, but with use of ethanol or trifluoroethanol, results in the corresponding ethoxy‐ and trifluoroethoxy acetals. These compounds can be converted into the oxabicyclic compounds 15, which undergo cleavage of the ether bridge on heating with KOH in methanol, thus providing 2‐alkoxy‐3‐hydroxytropones 20, which can be dealkylated to give the 2,7‐dihydroxytropones (7‐hydroxytropolones) 29. The lithium enolate generated from the α‐oxo acetal 15a can be exo‐alkylated with methyl iodide. Michael addition with 2‐nitro‐1‐butene followed by a Nef reaction furnishes the bicyclic dioxo acetal 5. Treatment of 5 with basic methanol results in an epoxyazulenone derivative 26, and a hydroxytropone 20f, which is in equilibrium with the cyclic hemiacetal form 28. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…[29,30]. [20] qui ne mentionne pas de tropolones, tandis que d'autres auteurs rapportent la présen-ce des trois thujaplicines [87,88,91,92]. Cette espèce a été divisée par Li [50] en deux sous-espèces, l'une située dans l'hémisphère sud (Ch.…”

Section: Aspects Botaniquesunclassified

“…Plus fréquem-ment, le bois est extrait avec de l'éther éthylique ou de l'acétone ; les tropolones peuvent être purifiées par leur transformation en complexes cuivriques qui se décompo-sent à leur tour en présence de H 2 S. Les sels avec la dicyclohexylamine, la cyclohexylamine ou la benzylamine [91,92] α -T h u y a p l i c i n e β -T h u y a p l i c i n e γ -T h u y a p l i c i n e β -D o l a b r i n e α -T h u y a p l i c i n o l β -T h u y a p l i c i n o l P i g m a é i n e I s o p i g m a é i n e α -D o l a b r i n o l N o o t k a t i n e N o o t k a t i n o l P r o c é r i n e C h a n o o t i n e C h a m a é c i n e utilisés pour l'extraction des tropolones. Ces dernières sont stables à l'obscurité, tandis que les complexes cuivriques des hydroxytropolones semblent être plus instables [91,92]. Les méthodes habituelles d'isolement, telles que l'extraction liquide-liquide, l'entraînement à la vapeur et l'extraction au Soxhlet sont onéreuses ; elles nécessitent des températures élevées et sont souvent effectuées à la lumière, si bien qu'elles peuvent conduire à la décompo-sition de tropolones [62].…”

Section: Méthodes D'extraction Des Tropolonesunclassified

Caract�risation et origine des tropolones responsables de la durabilit� naturelle des Cupressac�es. Application potentielle en pr�servation du bois

Haluk

Roussel

2000

Ann. For. Sci.

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Résumé -L'objectif de cette revue est de présenter la nature chimique d'une famille de composés extractibles appelée tropolones, répertoriée dans l'ordre des Cupressales et considérée comme étant responsable de la durabilité naturelle des essences contenant ces métabolites secondaires. Des tropolones, en particulier les α, β et γ-thujaplicines, ont souvent été isolées à partir de Cupressacées (Cupressus, Chamaecyparis, Juniperus, Thuja, …) qui possèdent en effet un bois très résistant à la biodégradation. Des études déjà anciennes ont montré la toxicité importante des tropolones vis-à-vis des champignons de la pourriture du bois et des insectes. Il serait donc intéressant de pouvoir exploiter cette propriété au niveau industriel en substituant les agents chimiques de préservation du bois (CCA, etc.) par des molécules naturelles biocides. Ce concept peut donc constituer un enjeu prometteur pour le respect de l'environnement. Comme l'extraction de ces substances par des méthodes habituelles (solvant, CO 2 supercritique) ou leur synthèse chimique, onéreuse et peu rentable, ne sont pas envisageables au niveau industriel, l'exploitation des biotechnologies végétales (cals, suspensions cellulaires) peut constituer une démarche judicieuse pour l'obtention rapide de ces molécules biocides. En effet, la biosynthèse des tropolones a été obtenue par culture cellulaire de Thuja plicata et des premiers essais d'imprégnation d'éprouvettes de bois avec un extrait brut obtenu à partir des cellules végétales tendent à confirmer l'efficacité antifongique de ce nouveau type de traitement de préservation du bois.tropolones / Cupressacées / durabilité naturelle / préservation du bois / biotechnologies végétales Abstract -Characterization and origin of tropolones responsible for the cupressales natural durability. Potential application to wood preservation. The aim of this review is to present the chemical structure of a group of compounds naturally found in the trees belonging to the Order of the Cupressales, and being considered responsible for this wood species natural durability: namely tropolones. These compounds, and particularly the α, β and γ-thujaplicin, have often been isolated from Cupressaceae (Cupressus, Chamaecyparis, Juniperus, Thuja, …), which timber is extremely resistant to biodegradation. Previous studies have shown the important inhibition properties of the tropolones towards wood-destroying fungi and insects. Then, it would be an environmental and safety challenge to use these properties at an industrial scale, as a substitution to the toxic wood preservatives (such as CCA). However, either the extraction of these molecules (solvent extraction, CO 2 supercritical fluid, …) or their synthesis are far too expensive for such an application. The use of biotechnologies (cals, cell suspensions, …) could be judicious solution to get a cost-effective production of tropolones. Biosynthesis of tropolones from cell cultures of Thuja plicata has already been assessed, and first wood impregnation trials with crude extracts ha...

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Paper Chromatography of the Tropolones of Cupressaceae II

Cited by 31 publications

References 0 publications

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

A Novel Synthesis of 2‐Alkoxy‐3‐hydroxytropones and 2,7‐Dihydroxytropones from Dialkoxy‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐ones

Caract�risation et origine des tropolones responsables de la durabilit� naturelle des Cupressac�es. Application potentielle en pr�servation du bois

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