95507-03-2Relevant academic research and scientific papers
Synthesis of natural products from the Indian neem tree Azadirachta indica
Veitch, Gemma E.,Pinto, Andrea,Boyer, Alistair,Beckmann, Edith,Anderson, James C.,Ley, Steven V.
, p. 569 - 572 (2008/04/12)
The synthesis of five natural products (3, 6, 7, 10, and 14), isolated from the Indian neem tree Azadirachta indica, is reported from a common intermediate (2). The judicious choice of transacetalization conditions allows efficient access to both the azadirachtinin (9 and 10) and the azadirachtin (3, 6, 7, and 14) skeletons
The synthesis of azadirachtin: A potent insect antifeedant
Ley, Steven V.,Abad-Somovilla, Antonio,Anderson, James C.,Ayats, Carles,Baenteli, Rolf,Beckmann, Edith,Boyer, Alistair,Brasca, Maria G.,Brice, Abigail,Broughton, Howard B.,Burke, Brenda J.,Cleator, Ed,Craig, Donald,Denholm, Alastair A.,Denton, Ross M.,Durand-Reville, Thomas,Gobbi, Luca B.,Goebel, Michael,Gray, Brian Lawrence,Grossmann, Robert B.,Gutteridge, Claire E.,Hahn, Norbert,Harding, Sarah L.,Jennens, David C.,Jennens, Lynn,Lovell, Peter J.,Lovell, Helen J.,De La Puente, Mary L.,Kolb, Hartmuth C.,Koot, Win-Jan,Maslen, Sarah L.,McCusker, Catherine F.,Mattes, Amos,Pape, Andrew R.,Pinto, Andrea,Santafianos, Dinos,Scott, James S.,Smith, Stephen C.,Somers, Andrew Q.,Spilling, Christopher D.,Stelzer, Frank,Toogood, Peter L.,Turner, Richard M.,Veitch, Gemma E.,Wood, Anthony,Zumbrunn, Cornelia
experimental part, p. 10683 - 10704 (2009/12/31)
We describe in full the first synthesis of the potent insect antifeedant azadirachtin through a highly convergent approach. An O-alkylation reaction is used to unite decalin ketone and propargylic mesylate fragments, after which a Claisen rearrangement constructs the central C8-C14 bond in a stereoselective fashion. The allene which results from this sequence then enables a second critical carboncarbon bond forming event whereby the [3.2.1] bicyclic system, present in the natural product, is generated via a 5-exo-radical cyclisation process. Finally, using knowledge gained through our early studies into the reactivity of the natural product, a series of carefully designed steps completes the synthesis of this challenging molecule.
A relay route for the synthesis of azadirachtin
Veitch, Gemma E.,Beckmann, Edith,Burke, Brenda J.,Boyer, Alistair,Ayats, Carles,Ley, Steven V.
, p. 7633 - 7635 (2008/09/19)
(Chemical Equation Presented) 22 Years in the making: Azadirachtin (1) was synthesized for the first time by a highly convergent approach, utilizing a Claisen rearrangement and a radical cyclization as key steps. End-game strategies relied on intermediate 2, which could be obtained by synthetic methods as well as by degradation of 1. Bn = benzyl, TBS = tert- butyldimethylsilyl.
Chemistry of Insect Antifeedants from Azadirachta Indica (Part 19): A Potential Relay Route for the Synthesis of Azadirachtin.
Denholm, Alastair A.,Jennens, Lyn,Ley, Steven V.,Wood, Anthony
, p. 6591 - 6604 (2007/10/02)
A potential relay route for the synthesis of azadirachtin (1) has been established.An advanced intermediate 4 has been prepared and methods to convert this back to the natural product has been developed, in particular, the reintroduction of the enol double bond using an acetal exchange process.
Stable extracts from neem seeds
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, (2008/06/13)
A neem seed extract containing azadirachtin with improved stability has been developed using a process involving dissolution of the crude neem seed extract in a polar solvent and removal of impurities by precipitation and/or treatment of the extract with an oxidizing agent. The resulting extract, optionally formulated as a wettable powder, is a useful insecticide for the control of foliar pests.
CHEMISTRY OF INSECT ANTIFEEDANTS FROM AZADIRACHTA INDICA (PART 11) : CHARACTERISATION AND STRUCTURE ACTIVITY RELATIONSHIPS OF SOME NOVEL REARRANGED AZADIRACHTINS.
Ley, Steven V.,Anderson, James C.,Blaney, Wally M.,Morgan, E. David,Sheppard, Richard N.,et al.
, p. 9231 - 9246 (2007/10/02)
Several novel rearrangement reactions of the natural product azadirachtin and related derivatives have been characterised using a combination of x-ray crystallographic and high field nmr techniques.The insect antifeedant properties of these and a number of C7 modified compounds have been investigated.
CHEMISTRY OF INSECT ANTIFEEDANTS FROM AZADIRACHTA INDICA (Part 3) REACTIONS ON THE C-22,23 ENOL ETHER DOUBLE BOND OF AZADIRACHTIN AND CONVERSION TO 22,23-DIHYDRO-23-&β-METHOXYAZADIRACHTIN.
Ley, Steven V.,Anderson, James C.,Blaney, Wally M.,Lidert, Zev,Morgan, E. David,et al.
, p. 5433 - 5436 (2007/10/02)
Azadirachtin (1) can be converted to the natural product 22,23-dihydro-23β-methoxyazadirachtin (2) via selective bromomethoxylation of the C-22,23 enol ether double bond and tri-n-butyltin hydride reduction; the corresponding acetic acid adduct on pyrolysis affords (1) in high yield.The antifeedant effects of the addition compounds were assessed.
