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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Cyclized 9,11-secosterol enol-ethers from the gorgonian Pseudopterogorgia americana
Yang-Qing He1, Stacee Lee Caplan2, Paul Scesa2
1Department of Applied Chemistry, Xi'an University of Technology, Xi'an 710048, China; Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States.
Abstract:
Chemical investigation of the MeOH extract from the gorgonian Pseudopterogorgia americana afforded two rare sterols, ameristerenol A (1) and B (2), both 9,11-secosterols possesses a seven-membered cyclic enol-ether in ring C, and ameristerol A (3) is the first example of a naturally occurring 9,11-secosterol containing a gorgosterol side chain with a C-24(28) double bond. Ameristerenol A (1) was converted to the sterol derivatives 4-6 to provide additional chemical diversity and comparison for biological screening. The structures of compounds 1-6, along with three related known analogues 7-9, were determined on the basis of extensive spectroscopic analysis and by comparison with literature data. Compound 6 exhibited slight cytotoxicity activity against human breast cancer cell line MDA-MB-231.
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