A new halicyclamine derivative, tetradehydrohalicyclamine B (1), was isolated from the marine sponge Acanthostrongylophora ingens, along with halicyclamine B (2) as proteasome inhibitors. Compound 1 is the second example found to have a pyridinium ring in the halicyclamine family. Although the relative configuration of 2 was previously determined by X-ray crystallographic analysis, here we determined the absolute configuration of 2 by ECD experiment. Compounds 1 and 2 inhibited the constitutive proteasome as well as the immunoproteasome. The inhibitory activities of 2 were 4- to 10-fold more potent than those of 1.

中文翻译：

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Tetradehydrohalicyclamine B，一种新的蛋白酶体抑制剂，来自海洋海绵Acanthostrongylophora ingens

从海洋海绵Acanthostrongylophora ingens中分离了一种新的盐环胺衍生物四氢卤环胺B（1），以及作为蛋白酶体抑制剂的盐环胺B（2）。化合物1是第二个实例，该实例在卤代环胺家族中具有一个吡啶鎓环。虽然相对配置2之前由X-射线晶体学分析确定的，在这里我们确定的绝对构型2由ECD实验。化合物1和2抑制组成型蛋白酶体以及免疫蛋白酶体。2的抑制活性效力比1强4至10倍。