Chemistry of insect antifeedants from azadirachta indica (part 1): Conversion from the azadirachtin to the azadirachtinin skeletons

✍ Scribed by John N. Bilton; Philip S. Jones; Steven V. Ley; Nicholas G. Robinson; Richard N. Sheppard

• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 224 KB
• Volume: 29
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)82061-4

✦ Synopsis

The conversion of azadirachtin derivatives to the corresponding azadirachtinii skeletons can be achieved in high yield under mild conditions.

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A. Juss is a source of compounds possessing several potent biological activities. However, recent attention has been centred around one compound, amdirachtin (l), which is a very strong insect antifeedant and ecdysis inhibitor. Its structure was only recently determined, requiring the careful application of modem n.m.r., x-ray crystallographic and mass spectral techniques by the groups of L.ey,r Krausz and Nakanishi.3

We remain interested in the chemistry of azadimchtin for several reasons. Most immediately we require a sound knowledge of its chemistry as an aid to the rational and flexible design of the later steps in our total synthesis of azadirachtin. Secondly, the production of modified azadimchtins is of use in biological studies on the mechanism of action of insect antifeedants. Finally, the understanding of the chemical reactivities and structure-activity relationships of azadirachtin derivatives, or simpler synthetic analoguesP is commercially important. In this letter we describe a series of rearrangement reactions involving opening of the C-13,14 epoxide. Other chemical and biological studies will be reported elsewhere?