Pyrazolofluostatins A–C, Pyrazole-Fused Benzo[<i>a</i>]fluorenes from South China Sea-Derived <i>Micromonospora rosaria</i> SCSIO N160
2017-01-11T18:53:28Z (GMT) by
Pyrazolofluostatins A–C (<b>1</b>–<b>3</b>), three new benzo[<i>a</i>]fluorenes with an unprecedented carbon skeleton, were obtained from the South China Sea-derived <i>Micromonospora rosaria</i> SCSIO N160. Their structures were elucidated by extensive spectroscopic analyses. The structure of pyrazolofluostatin A (<b>1</b>) was confirmed by X-ray crystallographic analysis. Notably, <b>1</b>–<b>3</b> possessed a benzo[<i>cd</i>]indeno[2,1-<i>f</i>]indazol skeleton with a pyrazole-fused 6/5/6/6/5 pentacyclic ring system. Pyrazolofluostatin A (<b>1</b>) showed moderate antioxidation activity (EC<sub>50</sub> 48.6 μM).