Yang-Qing He¹, Stacee Caplan², Paul Scesa²,and Lyndon M. West². ¹Department of Applied Chemistry, Xi’an University of Technology, Xi’an, Shaanxi 710054, P. R. China, ²Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, USA

Chemical investigation of the MeOH extract from the gorgonian Pseudopterogorgiaamericana afforded two rare sterols, ameristerenol A (1) and B (2), both 9,11-secosterols containing a seven-membered cyclic enol-ether in ring C, and ameristerol A (3), the first 9,11-secosterol containing a gorgosterol side chain containing an exocyclic methylene group at C-24, along with three related known analogues. Ameristerenol A (1) was converted to semi-synthetic sterols 4-6. The structures of compounds 1-6 were determined on the basis of extensive spectroscopic analysis and by comparison with literature data.

Acknowledgment.This research wassupported by National Institutes of Health grants (P41GM079597 and P01GM085354) and by the Starting grant of Xi’an University of Technology awarded to Dr. Yangqing He (108-211409) and Youth Scientists Innovation Team Program Funded by Xi’an University of Technology (108-211408).