Synthesis and ring contraction reactions of polyazamacrolides.
Synthesis and ring contraction reactions of polyazamacrolides.
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聚氮杂环内酯的合成和缩环反应。
DOI：
10.1021/jo001247h
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Meinwald,J
中科院分区：
文献类型：
--
作者：
García-Rubio,S;Meinwald,J
合成了瓢虫（Epilachna borealis）防御分泌物中最丰富的单一成分，三聚体42元聚氮杂环内酯PAML 681的三个类似物。非天然大环三聚体的构建始于相应单体片段的制备，然后是它们的低聚，最后是活化的线性三聚羟基酸的大内酯化步骤。研究了paml681本身及其合成类似物所特有的正o-酰基迁移的相对速率。这些研究表明，亲核氮原子附近取代模式的变化，以及杂氮环中间体大小的变化，对聚氮杂环内酯重排速率有实质性的影响。
The synthesis of three analogues of the single most abundant component of a ladybird beetle (Epilachna borealis) defensive secretion, the trimeric 42-membered polyazamacrolide PAML 681, is described. Construction of the nonnatural macrocyclic trimers began with the preparation of the corresponding monomeric segments, followed by their oligomerization and a final macrolactonization step of the activated linear trimeric hydroxy acid. The relative rates of theO-to-Nacyl migrations that are characteristic of PAML 681 itself, as well as of the synthetic analogues, were investigated. These studies showed that changes in the substitution pattern adjacent to the nucleophilic nitrogen atom, along with changes in the size of the oxaazacyclic intermediates, have substantial effects on the polyazamacrolide rearrangement rates.