- Amicoumacins from the marine-derived bacterium Bacillus sp. with the inhibition of NO production
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Chemical examination of the fermentation broth of the marine-derived bacterium Bacillus sp. resulted in the isolation of seven new amicoumacin-type isocoumarin derivatives, namely bacillcoumacins A-G (1-7), together with four known analogues. Their structures were elucidated on the basis of extensive spectroscopic analysis, while the absolute configurations of the new compounds were determined by CD, Mosher's method, and chemical conversion. Compounds 7 and 9 showed inhibitory effects against the NO production induced by lipopolysaccharide (LPS) in mouse macrophage RAW 264.7 cells.
- Bai, Jian,Liu, Dong,Yu, Siwang,Proksch, Peter,Lin, Wenhan
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- Efficient total synthesis of AI-77-B, a gastroprotective substance from Bacillus pumilus AI-77
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First total synthesis of AI-77-B (1), a gastroprotective substance from Bacillus pumilus AI-77, was achieved in a stereoselective and convergent manner. In this synthesis, the dihydroisocoumarin part 2 was constructed in one step through 1,2-addition of the benzylic anion 17b to Boc-L-leucinal 7b. The hydroxy amino acid 4 was elaborated from (R)-glutamic acid in a highly stereoselective manner. Condensation of 2·HCl and 4, intramolecular Pinner reaction, followed by mild hydrolysis afforded AI-77-B (1).
- Hamada,Hara,Kawai,Kohno,Shioiri
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p. 8635 - 8652
(2007/10/02)
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