Recent advances in the chemistry of caryophyllene

Collado, Isidro G.; Hanson, James R.; Macı́as-Sánchez, Antonio J.

doi:10.1039/a815187y

Cited by 93 publications

(102 citation statements)

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“…[19][20][21][22] There have been many conflicts and disagreements concerning absolute configurations and structures of caryophyllene derivatives isolated from natural sources. [7][8][9]23 The buds of B. pendula, B. litwinowii and B. medwediewii collected from various parts of Turkey were hydrodistilled while B. browicziana and B. recurvata buds were subjected to simultaneous distillation-extraction method (SDE) using a Likens-Nickerson apparatus due to limited plant material.…”

Section: Resultsmentioning

confidence: 99%

Studies on Betula essential oils

Başer¹,

Demırcı²

2007

Arkivoc

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Essential oils were obtained from leaf, branch and buds of Betula species: B. pendula Roth, B. browicziana A.Güner, B. litwinowii Doluch., B. recurvata V. Vassil., and B. medwediewii Regel naturally growing in various parts of Turkey. Also buds of the common birch B. pendula essential oil from Germany and two species native to Finland namely, Betula pubescens ssp. czerepanovii (Orlova) Hämet-Ahti and Betula pubescens ssp. pubescens Erhr. were investigated. Betula essential oils were obtained by different distillation techniques such as hydrodistillation, microdistillation and Likens-Nickerson simultaneous distillation-extraction method (SDE). The resulting volatile compositions were elucidated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) systems. Known and new sesquiterpenes were isolated from Betula essential oils using column chromatographic techniques. Structure determination of each isolated compound was carried out using 1D and 2D NMR spectroscopic techniques supported by MS, UV and GC FITR. Biological activities were determined both for essential oils and pure compounds isolated from the oils of Betula species. Antifungal, antibacterial and antioxidant activity results were carried out using various in vitro techniques.

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Section: Resultsmentioning

confidence: 99%

Studies on Betula essential oils

Başer¹,

Demırcı²

2007

Arkivoc

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“…Separation of alcohol 12 was achieved by using silica gel column chromatography, but in the case of 13, this compound could only be isolated as its acetate derivative 13a after semipreparative HPLC following acetylation of a mixture containing it. The NMR spectroscopic data of alcohol 12 and acetate 13a (Table 1) were again consistent with a skeleton of 1,4,4-trimethyltricyclo[6.3.0.0 2,5 ]-undecan-9-ol. The stereochemistry of both 12 and 13a was determined after comparing their spectroscopic data with those of alcohols 8-11 ( Table 1).…”

Section: Resultsmentioning

confidence: 58%

“…Some examples are the radical-induced addition of acetaldehyde to the caryophyllene skeleton, [9] irradiation in an anionic micellar medium of β-caryophyllene (1) in the presence of an electron acceptor, [13] and the reduction of β-caryophyllene (2 and 3) and isocaryophyllene (4 and 5) epoxides with lithium in liquid ammonia. [14] All of these radical transformations led, with yields below 50 %, to structures derived from tricyclo[6.3.0.0 2,5 ]undecane. Titanocene chloride has been widely used in the radical cyclization of epoxypolyenes.…”

Section: Introductionmentioning

confidence: 99%

Transannular Cyclization of Epoxycaryophyllenes Catalyzed by Ti^III: An Efficient Synthesis of Tricyclo[6.3.0.0^2,5]undecanes

Barrero¹,

Herrador²,

Moral³

et al. 2006

Eur J Org Chem

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The transannular cyclization of epoxycaryophyllenes 2–7 catalyzed by TiIII has been investigated. This cyclization led to alcohols 8–15, all of them possessing a tricyclo[6.3.0.02,5]undecane skeleton. All of these compounds present pleasant aromatic properties. The cyclization takes place with high yields (> 80 %) and via the αα or ββ conformation of the intermediate radical I. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…Compound II was isolated from the reaction mixture by recrystallization from hexane; its oxidation with monoperoxyphthalic acid afforded diepoxy derivative III (Scheme 1) [2]. It should be noted that epoxidation of caryophyllene 4β,5α-epoxide gave two epimeric diepoxy derivatives.…”

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confidence: 99%

Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis

et al. 2005

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Transformations of isocaryophyllene diepoxide (an isomer of widely spread natural sesquiterpene) were studied in various acidic media under conditions of homogeneous and heterogeneous catalysis. A number of previously unknown compounds were thus obtained. The experimental data were compared with the results of molecular-mechanics and quantum-chemical simulation of the most probable transformation paths.We previously studied acid-catalyzed transformations of diepoxy derivatives of caryophyllene (which is one of the most widely spread natural sesquiterpenes) over solid catalysts and under homogeneous conditions [1]. With a view to elucidate how the substrate structure affects the results of transformations, in the present work we examined transformations of isomeric isocaryophyllene diepoxide under conditions of homogeneous and heterogeneous catalysis. Isocaryophyllene (I) is the cis isomer of caryophyllene with respect to the 4(5)-double bond; like caryophyllene, compound I readily undergoes cyclization in the presence of acids; however, the composition of the cyclization products is different due to the lack of strain at the endocyclic 4(5)-double bond [2, 3].Treatment of diene I with a peroxy acid gives rise to epimeric epoxy derivatives as a result of oxidation of the 4(5)-double bond, 4β,5β-(II) and 4α,5α-epoxyisocariophyllenes. Compound II was isolated from the reaction mixture by recrystallization from hexane; its oxidation with monoperoxyphthalic acid afforded diepoxy derivative III (Scheme 1) [2]. It should be noted that epoxidation of caryophyllene 4β,5α-epoxide gave two epimeric diepoxy derivatives. The reaction of II with peroxy acid was stereoselective.The most stable conformations of diepoxide III are almost equally strained αα and βα forms. The low barrier to interconversion between the conformers (as in the case of initial diene I) [4] rules out conformationally controlled reaction. The stable conformers were revealed using Dreiding models and molecular dynamics calculations. The heats of formation of possible conformers were estimated in terms of the PM3 semiempirical method, and the most stable conformers (within 5 kcal/mol) were calculated by the DFT method (B3LYP/6 31G*). Scheme 1 shows the best (within 2 kcal/mol) conformers according to the DFT calculations.The synthesis of diepoxy derivative III and its transformations in nucleophilic media were described in [5]. It was shown that the 4,5-epoxy group is stable in alkaline medium; therefore, the corresponding 8,13-diol is formed, and the latter undergoes intramolecular cyclization to give tricyclic product (Scheme 1). Acid-catalyzed transformations of diepoxide III were not studied previously.Isomerization of compound III over solid catalysts (such as β-zeolite or askanite-bentonite clay) leads to formation of dialdehyde IV and tricyclic hydroxy aldehyde Va; in addition, compounds VI and VII at a ratio of 1 : 0.4 (according to the 1 H NMR data) were isolated from the reaction mixture. Compound IV and tricyclic hydroxy aldehyde Vb (which is ste...

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Recent advances in the chemistry of caryophyllene

Cited by 93 publications

References 104 publications

Studies on Betula essential oils

Studies on Betula essential oils

Transannular Cyclization of Epoxycaryophyllenes Catalyzed by Ti^III: An Efficient Synthesis of Tricyclo[6.3.0.0^2,5]undecanes

Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis

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Recent advances in the chemistry of caryophyllene

Cited by 93 publications

References 104 publications

Studies on Betula essential oils

Studies on Betula essential oils

Transannular Cyclization of Epoxycaryophyllenes Catalyzed by TiIII: An Efficient Synthesis of Tricyclo[6.3.0.02,5]undecanes

Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis

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Transannular Cyclization of Epoxycaryophyllenes Catalyzed by Ti^III: An Efficient Synthesis of Tricyclo[6.3.0.0^2,5]undecanes