New diterpenes, isocembrene and isocembrol, in the oleoresin ofPinus sibirica

Kashtanova, N. K.; Lisina, A. I.; Pentegova, V. A.

doi:10.1007/bf00567769

Cited by 5 publications

(4 citation statements)

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“…strategy, the authors achieved the total synthesis of (±)-isocembrene (Scheme 33), a natural 14-membered carbocycle first isolated in 1968 from the Russian pine tree Pinus sibirica [44].…”

Section: Scheme 32mentioning

confidence: 99%

Vinyl and Aryl Sulfonates: Preparations and Applications in Total Synthesis

Chassaing

Specklin²,

Weibel³

et al. 2012

COS

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Vinyl and aryl sulfonates are ubiquitous building blocks in organic chemistry, frequently exploited in the total synthesis of natural and non-natural products, due to their ease of formation and to their high reactivity, especially in metal-catalyzed cross-coupling reactions. The present review thus aims at first describing the classical and current methods to prepare these valuable synthons, with an emphasis on reaction mechanisms. The second part of the review aims at highlighting their main applications in organic synthesis, especially in the course of natural product total syntheses.

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“…strategy, the authors achieved the total synthesis of (±)-isocembrene (Scheme 33), a natural 14-membered carbocycle first isolated in 1968 from the Russian pine tree Pinus sibirica [44].…”

Section: Scheme 32mentioning

confidence: 99%

Vinyl and Aryl Sulfonates: Preparations and Applications in Total Synthesis

Chassaing

Specklin²,

Weibel³

et al. 2012

COS

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“…One of these derivatives, isocembrol (1), was isolated from Siberian cedar resin [7] and was studied for possible generation of the eleutheside carbon skeleton [8]. In contrast with this, we used hydroxy derivatives of isocembrol directly as the alcohols of N-methylurocanate esters.…”

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confidence: 99%

Synthesis of N-methyl urocanates of hydroxyderivatives of isocembrol

et al. 2007

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Alcohols were prepared by stereospecific hydroxylation of isocembrol and were esterified into N-methylurocanates, proposed biomimetics of taxol.Urocanic [3-(4-imidazolyl)prop-2-enoic] acid exhibits multifaceted biological activity and is formed in vivo as a result of histidine metabolism [1]. Its N-methylderivative is the acid component in the diterpene esters eleutherobin and sarcodictyins, metabolites of soft coral Eleutherobia sp. and Sarcodictyon roseum, which exhibit a taxol-like mechanism of cytotoxic activity [2]. In creating a combinatory library of sarcodictyins, it was discovered that removal of the N-methylurocanic acid or replacing its imidazole ring by oxazole, thiazole, or benzene sharply affected its cytotoxic activity [3]. Valdivones, eleuthesides that are not N-methylurocanate esters [4], have not been demonstrated to have similar properties. On the other hand, an eleuthesoid containing a benzene ring instead of menthane retains its cytotoxic activity [5]. It may be that the biological properties of eleutherobin and sarcodictyin are unique because they are also N-methylurocanate esters, which makes it probable that other accessible taxol biomimetics exist.Therefore, cembrane derivatives, which are proposed biogenetic precursors of eleuthesides [6], are promising diterpenoids for preparing N-methylurocanates. One of these derivatives, isocembrol (1), was isolated from Siberian cedar resin [7] and was studied for possible generation of the eleutheside carbon skeleton [8]. In contrast with this, we used hydroxy derivatives of isocembrol directly as the alcohols of N-methylurocanate esters.We studied the possibility of introducing selectively a secondary hydroxyl into the molecule because esterification of the tertiary alcohol of 1 is problematical due to steric hindrances and competing elimination. Scheme 1.

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“…8 Our continuing chemical investigation on this soft coral has again led to the isolation of two new hydroxylated cembranes 1 and 2, along with two known metabolites 3 (diepoxycembrane A) 9 and 4 (isocembrol). 10 The structures of two new metabolites were determined on the basis of extensive spectroscopic analysis, including 2D NMR ( 1 H 1 H COSY, HMQC, HMBC, and NOESY) spectroscopy. Cytotoxicity of metabolites 14 against a limited panel of human tumor cell lines including liver (Hep G2 and Hep G3B), breast (MDA-MB-23), and gingival (Ca9-22) carcinoma cells are also studied.…”

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confidence: 99%

Two New Cembranes from a Formosan Soft Coral Sinularia facile

Chen¹,

Su²,

Dai³

et al. 2011

Bulletin of the Chemical Society of Japan

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Two new hydroxycembranes 1 and 2 and two known epoxycembrane 3 and isocembrol 4 have been isolated from a Formosan soft coral Sinularia facile. The structures of new metabolites were elucidated on the basis of extensive spectroscopic analysis and cytotoxic activity of 14 against the proliferation of a limited panel of cancer cell lines was measured.Formosan soft corals of the genus Sinularia have been found to be a rich source of bioactive secondary metabolites, such as cembranoids 14 and steroids. 5,6 Although the chemical constituents of the soft coral Sinularia facile (Durivault) have rarely been studied, two cembranes were isolated from this marine organism. 7 Our previous chemical investigation on the Formosan soft coral S. facile have afforded five new polyoxygenated steroids. 8 Our continuing chemical investigation on this soft coral has again led to the isolation of two new hydroxylated cembranes 1 and 2, along with two known metabolites 3 (diepoxycembrane A) 9 and 4 (isocembrol). 10 The structures of two new metabolites were determined on the basis of extensive spectroscopic analysis, including 2D NMR ( 1 H 1 H COSY, HMQC, HMBC, and NOESY) spectroscopy. Cytotoxicity of metabolites 14 against a limited panel of human tumor cell lines including liver (Hep G2 and Hep G3B), breast (MDA-MB-23), and gingival (Ca9-22) carcinoma cells are also studied. We report herein the isolation, structure elucidation, and bioactivity of these compounds.The sliced bodies of the soft coral S. facile were extracted exhaustively with EtOH, and then the concentrated EtOH extract was partitioned between EtOAc and H 2 O. The combined EtOAc-soluble fraction was concentrated under reduced pressure and the residue was repeatedly chromatographed to yield metabolites 14.Compound 1 was isolated as a colorless oil. Its molecular formula, C 20 H 32 O, was established by HR-ESI-mass spectrum (m/z 311.2352 [M + Na] + ) and 13 C NMR spectroscopic data, implying five degrees of unsaturation. The IR absorption was observed at 3368 cm ¹1 , suggesting the presence of a hydroxy group. The structure of this compound was deduced from its 13 C NMR and DEPT spectra, which showed that the compound has 20 carbons, including four methyls, eight methylenes (including one sp 2 CH 2 ), three sp 2 methines, and one sp 3 quaternary carbon. From 1 H and 13 C NMR spectra (Tables 1 and 2), 1 was found to possess three trisubstituted olefinic groups [¤ H 5.27 (t, J = 7.5 Hz), ¤ C 137.9 (qC), 120.4 (CH); ¤ H 4.94 (t, J = 5.3 Hz), ¤ C 133.7 (qC), 125.9 (CH); ¤ H 5.06 (t, J = 6.5 Hz), ¤ C 136.

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New diterpenes, isocembrene and isocembrol, in the oleoresin ofPinus sibirica

Abstract: From the neutral part of the oleoresin of Pinus sibirica (R) blayr, we have isolated two New diterpene compounds with 14-membered rings: a hydrocarbon C20[taaO, which we have called isocembrene (I) and isocembrol (II).

Cited by 5 publications

References 1 publication

Vinyl and Aryl Sulfonates: Preparations and Applications in Total Synthesis

Vinyl and Aryl Sulfonates: Preparations and Applications in Total Synthesis

Synthesis of N-methyl urocanates of hydroxyderivatives of isocembrol

Two New Cembranes from a Formosan Soft Coral Sinularia facile

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