Montecrinanes A-C: Triterpenes with an Unprecedented Rearranged Tetracyclic Skeleton from Celastrus vulcanicola. Insights into Triterpenoid Biosynthesis Based on DFT Calculations
Author
dc.contributor.author
Purino, Martín
Author
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Ardiles, Alejandro E.
Author
dc.contributor.author
Callies, Oliver
Author
dc.contributor.author
Jiménez, Ignacio A.
Author
dc.contributor.author
Bazzocchi, Isabel L.
Admission date
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2017-01-31T20:06:58Z
Available date
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2017-01-31T20:06:58Z
Publication date
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2016
Cita de ítem
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Chem. Eur. J. 2016, 22, 7582 – 7591
es_ES
Identifier
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10.1002/chem.201600294
Identifier
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https://repositorio.uchile.cl/handle/2250/142804
Abstract
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Three new triterpenoids with an unprecedented 6/6/6/6-fused tetracyclic carbon skeleton, montecrinanes A-C (1-3), were isolated from the root bark of Celastrus vulcanicola, along with known D:B-friedobaccharanes (4-6), and lupane-type triterpenes (7-12). The stereostructures of the new metabolites were elucidated based on spectroscopic (1D and 2D NMR) and spectrometric (HR-EIMS and HR-ESIMS) techniques. Their absolute configurations were determined by both NMR spectroscopy, with (R)-(-)-alpha-methoxy-phenylacetic acid as a chiral derivatizing agent, and biogenetic considerations. Biogenetic pathways for montecrinane and D: B-friedobaccharane skeletons were proposed and studied by DFT methods. The theoretical results support the energetic feasibility of the putative biogenetic pathways, in which the 1,2-methyl shift from the secondary baccharenyl cation represents a novel and key reaction step for a new montecrinane skeleton.
Montecrinanes A-C: Triterpenes with an Unprecedented Rearranged Tetracyclic Skeleton from Celastrus vulcanicola. Insights into Triterpenoid Biosynthesis Based on DFT Calculations