Kobayashi J, Kubota T, Endo T, Tsuda M
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
J Org Chem. 2001 Jan 12;66(1):134-42. doi: 10.1021/jo005607c.
Three new 19-membered macrolides, amphidinolides T2 (2), T3 (3), and T4 (4), structurally related to amphidinolide T1 (1) have been isolated from two strains of marine dinoflagellates of the genus Amphidinium. The structures of 2-4 were elucidated on the basis of spectroscopic data. The absolute configurations at C-7, C-8, and C-10 of 1-4 were determined by comparison of NMR data of their C-1-C-12 segments with those of synthetic model compounds for the tetrahydrofuran portion. The biosynthetic origins of amphidinolide T1 (1) were investigated on the basis of 13C NMR data of a 13C enriched sample obtained by feeding experiments with [1-(13)C], [2-(13)C], and [1,2-(13)C2] sodium acetates and 13C-labeled sodium bicarbonate in the cultures of the dinoflagellate. These incorporation patterns suggested that amphidinolide T1 (1) was generated from four successive polyketide chains, an isolated C1 unit formed from C-2 of acetates, and three unusual C2 units derived only from C-2 of acetates. Furthermore, it is noted that five oxygenated carbons of C-1, C-7, C-12, C-13, and C-18 were not derived from the C-1 carbonyl, but from the C-2 methyl of acetates.
从两株叉鞭金藻属海洋甲藻中分离出了三种新的19元大环内酯类化合物,即安福霉素T2(2)、T3(3)和T4(4),它们在结构上与安福霉素T1(1)相关。根据光谱数据阐明了2-4的结构。通过将1-4的C-1-C-12片段的NMR数据与四氢呋喃部分的合成模型化合物的NMR数据进行比较,确定了1-4在C-7、C-8和C-10处的绝对构型。基于在甲藻培养物中用[1-(13)C]、[2-(13)C]和[1,2-(13)C2]醋酸钠以及13C标记的碳酸氢钠进行喂养实验获得的13C富集样品的13C NMR数据,研究了安福霉素T1(1)的生物合成起源。这些掺入模式表明,安福霉素T1(1)由四条连续的聚酮链、一个由醋酸盐的C-2形成的孤立C1单元以及三个仅来自醋酸盐C-2的不寻常C2单元产生。此外,值得注意的是,C-1、C-7、C-12、C-13和C-18的五个含氧碳并非来自C-1羰基,而是来自醋酸盐的C-2甲基。