Two new malyngamides from a Madagascan Lyngbya majuscula
Two new malyngamides from a Madagascan Lyngbya majuscula
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DOI：
10.1021/np000038p
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发表时间：
2000-07-01
影响因子：
5.1
通讯作者：
Gerwick, WH
中科院分区：
文献类型：
--
作者：
Milligan, KE;Márquez, B;Gerwick, WH
大鞘丝藻（Lyngbya majuscula）的脂质提取物已经产生了7-甲氧基十四碳-4-烯酸的两种酰胺--马林酰胺（malyngamides）Q和R。这些代谢产物的分离是使用制备液相色谱法完成的，最终通过重复反相HPLC纯化。利用天然产物的1D和2D NMR光谱表征以及与马林酰胺A和B的比较完成结构解析。DPFGSE ID NOE数据表明，在马林酰胺Q和R中，C-6处的几何立体化学与马林酰胺A以及其他已知的马林酰胺中观察到的几何立体化学不同。通过利用HSQMBC脉冲序列测量关键诊断性（3）J（CH）偶联，证实了马林酰胺R的Z立体化学。吡咯烷酮环的C-4”的绝对立体化学通过臭氧分解和酸水解释放的丝氨酸的手性GCMS分析来定义。
The lipid extract of a Madagascan Lyngbya majuscula has yielded malyngamides Q and R, both amides of 7-methoxytetradec-4-enoic acid. The isolation of these metabolites was accomplished using preparative liquid chromatography, with final purification through repetitive reversed-phase HPLC. Structure elucidation was accomplished utilizing 1D and 2D NMR spectroscopic characterization of the natural products and comparisons with malyngamides A and B. DPFGSE ID NOE data suggested a different geometrical stereochemistry at C-6 in malyngamides Q and R from that observed for malyngamide A, as well as the other known malyngamides. The Z stereochemistry was confirmed for malyngamide R by measurement of key diagnostic (3)J(CH) couplings utilizing the HSQMBC pulse sequence. The absolute stereochemistry of C-4" of the pyrrolidone ring was defined by chiral GCMS analysis of serine released by ozonolysis and acid hydrolysis.