Baccharis Oxide, a new Triterpenoid from Baccharis halimifolia L.

Anthonsen, T.; Bruun, Torger; Hemmer, Ellen; Holme, Dagny; Lamvik, Aud; Sunde, Erling; Sørensen, Nils Andreas

doi:10.3891/acta.chem.scand.24-2479

Cited by 33 publications

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“…Baccharis oxide, which should be produced by the same pathway to shionone until two steps before the C-4 cation (Fig. 1B), has been reported from the Baccharis species (Asteraceae) [28,29], and a few other Asteraceae plants including S. rebaudiana appear to be its producer [13,30]. SHS and BOS should have evolved specifically in the Asteraceae, and SHS must have acquired a high product specificity, due to a rather strict controls of the reaction pathway at the branching points (see Fig.…”

Section: Discussionmentioning

confidence: 58%

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Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone ofAster tataricus

et al. 2011

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a b s t r a c tShionone is the major triterpenoid component of Aster tataricus possessing a unique all six-membered tetracyclic skeleton and 3-oxo-4-monomethyl structure. To clarify its biosynthetic process, an oxidosqualene cyclase cDNA was isolated from A. tataricus, and the function of the enzyme was determined in lanosterol synthase-deficient yeast. The cyclase yielded ca. 90% shionone and small amounts of b-amyrin, friedelin, dammara-20,24-dienol, and 4-epishionone and was designated as a shionone synthase (SHS). Transcripts of SHS were detected in A. tataricus organs, confirming its involvement in shionone biosynthesis. SHS was shown to have evolved in the Asteraceae from bamyrin synthase lineages and acquired characteristic species-and product-specificities.

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Section: Discussionmentioning

confidence: 58%

“…Baccharis oxide, which should be produced by the same pathway to shionone until two steps before the C‐4 cation (Fig. 1B), has been reported from the Baccharis species (Asteraceae) [28,29], and a few other Asteraceae plants including S . rebaudiana appear to be its producer [13,30].…”

Section: Discussionmentioning

confidence: 64%

Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone ofAster tataricus

et al. 2011

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“…The two perhydrochrysene based triterpenes baccharis oxide (391) (483,484) and shionone (392) are biogenetically derived by backbone rearrangements similar to those portrayed above for glutinol (373) and friedelin (375), but originating from tetracyclic carbonium ion (346) prior to E ring closure (Scheme 30). If cyclization to the bridged oxide moiety of (391) immediately follows the C10 -+-Cg methyl rearrangement, the oxygen nucleophile enters syn to the departing methyl group.…”

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confidence: 90%

“…However, the Cs-+-C4 methyl migration in this rearrangement occurs syn to the epoxide group. The retro-biogenetic backhone rearrangement of dihydrobaccharis oxide to bacchar-12-ene-3ß-ol (394) may be effected with boron trifluoride in benzene (483). The reaction of 31X,4!X-epoxy shionane (393 with tx-epoxide) with boron trifluoride in benzene affords both the 3tx epimer of (394) and a partially rearranged isomer with the double bond in the 11 8 position (486).…”

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confidence: 99%

Biogenetic-Type Rearrangements of Terpenes

Coates

1976

Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

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“…The title compound was first isolated from the roots of Baccharis halimifolia L. by Anthonsen et al (1970).…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of the triterpenoid baccharis oxide: with a note on the use of various approaches in the tangent-refinement procedure

Mo¹

1973

Acta Crystallogr Sect B

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Baccharis oxide, C30H500, crystallizes in space group P212~21, with a=7.413 (1), b= 11-866 (2), c= 29.067 (10) A, Z= 4. The structure was solved by direct methods. Two different procedures for developing phases by the tangent formula have been used and the results are discussed. Least-squares refinement converged at an R of 0.043 based on 1971 Fob~ (Rw=0"044). An oxide bridge between C(3) and C(10) in the six-membered ring A makes this structure a novel one among the triterpenes. Repulsion between 1,3-diaxial substituents enhances the steric strain in the fused-ring system. The 1,3 contacts are responsible for a pronounced flattening and twisting of the trans-fused rings C and D. The molecular structure is largely determined by intramolecular factors. Efficient stacking of molecules in the crystal is acco.-nplished by van der Waals interactions.

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Baccharis Oxide, a new Triterpenoid from Baccharis halimifolia L.

Cited by 33 publications

References 0 publications

Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone ofAster tataricus

Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone ofAster tataricus

Biogenetic-Type Rearrangements of Terpenes

Crystal structure of the triterpenoid baccharis oxide: with a note on the use of various approaches in the tangent-refinement procedure

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