Synthesis And Fungicidal Activity Of Sclerotiorin Derivatives

With the widespread use of chemical pesticide, resistance has become a serious problem which has led huge loss in agriculture. This situation requires us to develop new pesticide with novel scaffold to meet the need of agriculture. Natural products as leads in the development of pesticide provide an efficient way to solve this problem. Sclerotiorin and its analogues have exhibit wide biological activities including antifungal activity which gives us cue during the searching of lead structure for novel fungicide development.We have synthesized 21 novel sclerotiorin derivatives by changing the side chain of natural sclerotiorin. The modification of the structure including halogenation at C5 position and acetylation of hydroxyl group at C7 position has been studied. The structures of all compounds were characterized by]H NMR,13C NMR and HRMS. The structures of some representative compounds were further elucidated by X-ray diffraction. The general structure of synthesized compounds was described as follow:During the research, we have screened the reaction conditions for the synthesis of o-alkynlbenzaldehyde which was the key intermediate in our synthetic route. Finally, we promoted this Sonogashira coupling reaction by microwave irradiation. What is more, we have also optimized some reaction operation, which promoted the yield and simplified the workup of reaction.Fungicidal assay was conducted for all the compounds and the results showed that some compounds exhibited good activity against specific fungi. Further screening will be conducted in the due course.