Synthesis and ring contraction reactions of polyazamacrolides.
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 the O-to-N acyl 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.
García-Rubio
S
S
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Meinwald
J
J
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D001517:Coleoptera; D018942:Macrolides / Q000138:chemical synthesis* / Q000737:chemistry*; D013058:Mass Spectrometry; D015394:Molecular Structure
D018942:Macrolides