We reported previously the discovery of the potent antimalarial 40-membered macrolide bastimolide A (1) from the tropical marine cyanobacterium Okeania hirsute. Continued investigation has led to the discovery of a new analogue, bastimolide B (2), a 24-membered polyhydroxy macrolide with a long aliphatic chain and unique terminal tert-butyl group. Its complete structure was determined by a combination of extensive spectroscopic methods and comparative analysis of its methanolysis products with those of bastimolide A. A methanolysis mechanism for bastimolide A is proposed, and one unexpected isomerization product of the C2–C3 double bond, 2-(E)-bastimolide A (3), was obtained. Bastimolide B (2) showed strong antimalarial activity against chloroquine-sensitive Plasmodium falciparum strain HB3. A preliminary investigation of the structure–activity relationship based on six analogues revealed the importance of the double bond as well as the 1,3-diol and 1,3,5-triol functionalities.

中文翻译：

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Bastimolide B，一种具有叔丁基的抗疟疾24成员海洋大环内酯类

我们之前曾报道过从热带海洋蓝藻Okeania hirsute发现有效的抗疟疾40元大环内酯内酯A（1）。不断的研究导致发现了一种新的类似物巴斯德莫利德B（2），具有长脂族链和独特的末端叔丁基的24元多羟基大环内酯。它的完整结构是通过广泛的光谱方法和甲醇分解产物与巴斯德莫利德A的比较分析而确定的。提出了巴斯德莫利德A的甲醇分解机理，以及一个意想不到的C2-C3双键异构化产物2-（E）-巴斯蒂莫利德A（3）。Bastimolide B（2）对氯喹敏感的恶性疟原虫HB3菌株显示出强大的抗疟疾活性。对基于六种类似物的构效关系的初步研究表明，双键以及1,3-二醇和1,3,5-三醇官能度的重要性。