Total Synthesis of (−)-Brevisin: A Concise Synthesis of a New Marine Polycyclic Ether
作者:Takefumi Kuranaga、Naohito Ohtani、Ryosuke Tsutsumi、Daniel G. Baden、Jeffrey L. C. Wright、Masayuki Satake、Kazuo Tachibana
DOI:10.1021/ol102925d
日期:2011.2.18
The first and highly efficient totalsynthesis of (−)-brevisin has been achieved. The title compound was synthesized in only 29 steps (longest linear sequence) from commercially available starting materials. The synthesis provided over 70 mg of a marine polycyclic ether compound.
6-Tuliposide B is a secondary metabolite occurring specifically in tulip anthers. Recently, a potent antibacterial activity of 6-tuliposide B has been reported. However, its molecular target has not yet been established, nor its action mechanism. To shed light on such issues, 6-tuliposide B and tulipalin B analogues were synthesized and a structure-activity relationship (SAR) was examined using a broad panel of bacterial strains. As the results of SAR among a total of 25 compounds, only tulipalin B and the compounds having 3',4'-dihydroxy-2'-methylenebutanoate (DHMB) moieties showed any significant antibacterial activity. Moreover, the 3'R analogues of these compounds displayed essentially the same activities as 6-tuliposide B and the structure of the 3'R-DMBA moiety was the same as that of the proposed active moiety of cnicin. These results suggest that 6-tuliposide B has the same action mechanism as proposed for cnicin and bacteria) MurA is one of the major molecular targets of 6-tuliposide B. (C) 2009 Elsevier Ltd. All rights reserved.