Cyclamenols E (1) and F (2), two bicyclic macrolactams possessing a cyclopentane moiety, were isolated from the Antarctic Streptomyces sp. OUCMDZ-4348. Their structures, including absolute configurations, were determined by spectroscopic analysis, chemical derivatization, and ECD calculation. Treatment of compound 1 with 2,2-dimethoxypropane and pyridinium p-toluenesulfonate in acetone/DMF led to the formation of acetonide 1a with an unexpected skeleton. Compound 1 showed moderate inhibitory activity against the gastric carcinoma cell line N87 with an IC₅₀ value of 9.8 μM, but no cytotoxicity was observed on the other 25 cancer cell lines tested.

中文翻译：

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Cyclamenols E和F，两个来自南极链霉菌种的具有环戊烷部分的非对映异构双环大内酰胺

从南极链霉菌（Speptomyces sp）中分离出了具有环戊烷部分的两个双环大内酰胺仙客来E（1）和F（2）。OUCMDZ-4348。它们的结构，包括绝对构型，是通过光谱分析，化学衍生化和ECD计算确定的。在丙酮/ DMF中用2，2-二甲氧基丙烷和对甲苯磺酸吡啶鎓处理化合物1导致形成具有意外骨架的丙酮化物1a。化合物1表现出对胃癌细胞系N87中等抑制活性，其IC ₅₀ 值为9.8μM，但是在测试的其他25个癌细胞系上未观察到细胞毒性。