Configurational Assignment of Cyclic Peroxy Metabolites Provides an Insight into Their Biosynthesis: Isolation of Plakortolides, <i>seco</i>-Plakortolides, and Plakortones from the Australian Marine Sponge <i>Plakinastrella clathrata</i>
作者:Ken W. L. Yong、James J. De Voss、John N. A. Hooper、Mary J. Garson
DOI:10.1021/np100620x
日期:2011.2.25
seco-plakortolides (10−13), and three plakortones (14−16), were isolated from the Australian sponge Plakinastrella clathrata. Structural elucidation, including relative configurational assignment, was based on extensive spectroscopic analysis, while the absolute configurations of 1−4 were deduced from 1H NMR analyses on MPA esters derived from Zn/AcOH reduction products. Diastereomeric sets of plakortolides
十六新化合物,包含九个新plakortolides K-S(1 - 9),四开环-plakortolides(10 - 13),和三个plakortones(14 - 16),购自澳大利亚海绵分离Plakinastrella苔。结构解析,包括相对构型的分配,是基于广泛的光谱分析中,同时的绝对构型1 - 4从推导11 H NMR分析衍生自Zn / AcOH还原产物的MPA酯。非对映异构体的侧柏化合物,例如K和L或M和N,在C-3 / C-4而不是C-6的构型不同,这是一种立体化学结果,损害了涉及分子氧的Diels-Alder环加成反应的生物合成途径到Δ 3,5- -diunsaturated脂肪酸前体。生物合成可以合理地涉及在将氢过氧基立体定向引入聚酮化合物衍生的前体中之后的6-氢过氧二烯酸中间体的环化。隔离塞科-β-邻苯二酚内酯在温和的条件下转变为螺内酯,并完全保留构型,表明C-6羟基攻击