Studies On Synthesis And Insecticidal Activity Of Celangulins Derivatives

There are three strategies to research and develop botanical pesticides. Firstly, the crude extracts are used as the pesticides. Secondly, the active compounds are isolated and its derivatives are synthesized. Thirdly, the active compounds are used as lead compounds to syhthesize and screen the new pesticides.Celangulins are compounds based on a β -dihydroagarofuran core structure with insecticidal activity from Celastrus angulatus Max. As environment acceptable-pesticides, celangulins have been studied financed by National Natural Science Foundation of China (No.30130130) .The active compound Celangulin-V, which is the main active compound against insect pest from Celastrus angulatus Max, was modified at its 6-OH and the core structure β-dihydroagarofuran polyol of Celangulins from the basic hydrolysis of the extract of the root bark of Celastrus angulatus Max was modified by combinatorial chemical method. The insecticidal activity of the derivatives of Celangulin-V and the library based on the β -dihydroagarofuran polyol were studied .The structures of some derivatives were elucidated mainly by NMR and MS. The main results are as follows.1 , The ester ,ether and ketone derivatives of Celangulin-V were prepared and the activity of the ester derivatives of Celangulin-V is as good as Celangulin-V. the activity of the ether derivatives of Celangulin-V is much better than Celangulin-V. and the Celangulin-V-ketone has no activity.2, Sesquiterpene polyol esters library were syntheszed based on the basic hydrolysis of the extract of the root bark of Celastrus angulatus Max which can offer the β -dihydroagarofuran polyol by combinatorial chemical method .In the library the compounds with insecticidal activity were isolated by bioassay-guided fractionation. Two new compounds with insecticidal activity against the larve of Mythimna separata.were isolated and their structures were elucidated as 2β.6α ,8β,13-tetraisobutanoyloxy-1β, 9α -trihydroxy - β-dihydroagarofuran(A), 1 β,2 β,6 α,8 β,13-pentaisobutanoyloxy-4 α,9α -dihydroxy- β-dihydroagarofuran(B) mainly by NMR and MS spectral data.