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Structural Elucidation and Bioinspired Total Syntheses of Ascorbylated Diterpenoid Hongkonoids A-D.
- Source :
-
Journal of the American Chemical Society . 2/21/2018, Vol. 140 Issue 7, p2485-2492. 8p. - Publication Year :
- 2018
-
Abstract
- Hongkonoids A-D (1-4), the first example of ascorbylated terpenoids featuring a unique 5,5,5-fused tricyclic spiroketal butyrolactone moiety and diterpenoid-derived long chain, were isolated from Dysoxylum hongkongense. Their structures were unambiguously assigned by a combination of spectroscopic data, chemical degradation, Xray crystallography, CD analysis, and total synthesis. The total syntheses of compounds 1-4 were effectively accomplished by a convergent strategy with the longest linear sequences of 12-14 steps and overall yields of 5.4- 9.6%. Notably, we exploited a bioinspired one-pot method to construct the key intermediate 14 from an easily made compound 12 by involving the cascade reactions of an elaborate Claisen rearrangement, deprotections, and a 5-exo-trig cyclization. The desired major epimer 14a was then transformed to the main building block 21. Assembly of 21 and the long chain vinyl iodide 7 was made by an NHK coupling reaction to furnish the framework of 1-4. Some of the hongkonoids and/or synthetic analogs showed significant to moderate inhibitory activities against NF-κB, 11β-HSD1, and sterol synthesis. The most active NF-κB inhibitor 34 exhibited distinct inhibition on the LPS-induced inflammatory responses in RAW 246.7 and primary BMDM cells. [ABSTRACT FROM AUTHOR]
- Subjects :
- *TRITERPENOIDS
*VITAMIN C
*PHENOLIC acids
*CYTOCHROMES
*METALLOPROTEINASES
Subjects
Details
- Language :
- English
- ISSN :
- 00027863
- Volume :
- 140
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 128201115
- Full Text :
- https://doi.org/10.1021/jacs.7b10135