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61.
The antibacterial 3-chloro-4-hydroxy-5-(3,7,11-trimethyldodeca-2,6,10-trienyl)-benzamide, and the antifungal strobilurins B and D were isolated from an unidentified South African soil fungus. 相似文献
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Cenek Kolar Manfred Gerken Hans-Peter Kraemer Karsten Krohn Haryanto Linoh 《Journal of carbohydrate chemistry》2013,32(2-3):223-234
ABSTRACT The synthesis of 7-O-α-L-daunosaminyl-4-O-methyl-β-rhodomycinone (3) and the determination of its cytotoxic potency compared to that of the natural 7-O-α-L-dau-nosaminyl-β-rhodomycinone (4) are described. Starting with natural β-rhodomycinone (7), trimethylsilyl protecting groups were attached to the hydroxy groups at position 7 and 10, and the 4-OH group was subsequently methylated (MeI/Cs2CO3), thus providing the 4-O-methyl-7, 10-bis-O-trimethylsilyl-β-rhodomycinone (10). The two TMS groups were then deblocked to give 4-O-methyl-β-rhodomycinone (12). In a 3-stage synthesis 12 was converted into 4-O-methyl-10-O-trifiuoroacetyl-ß-rhodomycinone (15) to which l, 4-bis-O-p-nitrobenzoyl-3-N-trifluoroacetyl-L-daunosamine 16 was selectively linked to afford the 7-O-α-glycoside 17. The acyl protective groups are removed by treatment with 1N NaOH to give 3. 相似文献
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Wabo HK Kouam SF Krohn K Hussain H Tala MF Tane P Ree Tv Hu Q Schulz B 《Chemical & pharmaceutical bulletin》2007,55(11):1640-1642
Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V(1) (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium. 相似文献
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Krohn K Cludius-Brandt S Schulz B Sreelekha M Shafi PM 《Natural product communications》2011,6(11):1595-1596
Several biologically active alkaloids (1-4, 6), including a new quinazoline-6-carboxylic acid (1), were isolated from the medicinal plant Zanthoxylum rhetsa, an evergreen tree, native to subtropical areas. Whereas the pharmacological properties of the plant extract and single constituents have been widely tested, we now show that all of the metabolites have antialgal activities, all but 6 are antibacterial, and 6 and the reduction product 5 (derived from 4) are also antifungal. 相似文献
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