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Updated: Jul 3, 2026

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
Total synthesis, revised structure, and biological evaluation of biyouyanagin A and analogues thereof
K C Nicolaou1, T Robert Wu, David Sarlah
1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA. kcn@scripps.edu
Abstract:
Isolated from Hypericum species H. chinese L. var. salicifolium, biyouyanagin A was assigned structure 1a or 1b on the basis of NMR spectroscopic analysis. This novel natural product exhibited significant anti-HIV properties and inhibition of lipopolysaccharide-induced cytokine production. Described herein are the total syntheses of biyouyanagin A and several analogues (3-11), structural revision of biyouyanagin A to 2b, and the biological properties of all synthesized compounds. The total synthesis proceeded through cascade sequences that efficiently produced enantiomerically pure key building blocks 15b (ent-zingiberene) and 18 (hyperolactone C) and featured a novel [2 + 2] photoinduced cycloaddition reaction which occurred with complete regio- and stereoselectivity. Biological investigations with the synthesized biyouyangagins A (2-11) and hyperolactones C (12-16) revealed that the activity of biyouyanagin A most likely resides in its hyperolactone C structural domain.
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