Asymmetric Total Synthesis and Absolute Stereochemistry of the Neuroactive Marine Macrolide Palmyrolide A
作者:Rodolfo Tello-Aburto、Emily M. Johnson、Cheyenne K. Valdez、William A. Maio
DOI:10.1021/ol300673m
日期:2012.4.20
The firstasymmetric total synthesis and determination of the absoluteconfiguration for the neuroactive marine macrolide palmyrolide A is described. The highlight of the synthesis is macrocyclization via trans-enamide formation catalyzed by copper(I) iodide and cesium carbonate. Comparison with the authentic spectral data confirms the synthesis of (+)-ent-palmyrolide A.
描述了神经活性海洋大环内酯棕榈内酯 A 的第一次不对称全合成和绝对构型的确定。该合成的亮点是通过由碘化铜 (I) 和碳酸铯催化的反式烯酰胺形成进行大环化。与真实光谱数据的比较证实了 (+)- ent- palmyrolide A的合成。
Detailed Analysis of (−)-Palmyrolide A and Some Synthetic Derivatives as Voltage-Gated Sodium Channel Antagonists
作者:Suneet Mehrotra、Brendan M. Duggan、Rodolfo Tello-Aburto、Tara D. Newar、William H. Gerwick、Thomas F. Murray、William A. Maio
DOI:10.1021/np500644k
日期:2014.11.26
A small library of synthetic (-)-palmyrolide A diastereomers, analogues, and acyclic precursors have been examined with respect to their interaction with voltage-gated sodium channels (VGSCs). Toward this goal, the ability of (-)-palmyrolide A and analogues to antagonize veratridine-stimulated Na(+) influx in primary cultures of mouse cerebrocortical neurons was assessed. We found that synthetic (-)-palmyrolide A and its enantiomer functioned as VGSC antagonists to block veratridine-induced sodium influx. A detailed NMR and computational analysis of four diastereomers revealed that none had the same combination of shape and electrostatic potential as exhibited by natural (-)-palmyrolide A. These data indicate that the relative configuration about the tert-butyl and methyl substituents appears to be a prerequisite for biological function. Additional testing revealed that the enamide double bond was not necessary for blocking veratridine-induced sodium influx, whereas the acyclic analogues and other macrolide diastereomers tested were inactive as inhibitors of VGSCs, suggesting that the intact macrolide was required.