Study On Synthesis And Biological Activity Of Valinamide Derivatives

Since the1980s, discovery of new pesticides has entered a whole new stage, and the efficient, lowtoxicity, environment friendly pesticides have become a new trend. Because of its simple structure,low-toxicity, low-residue and widespread biological activities, some of-amino acid derivatives havedrawn our attention.The valinamide fungicides were a kind of novel biomimetic structure fungicides with satisfiedactivity against diseases caused by oomycete pathogens. The pesticide iprovalicarb launched by Bayer,benthiavalicarb-isopropyl launched by Kumiai Chemical, and the pesticide valifenalate recentlylaunched by Isagro have gained access to crop protection market.In order to create new and high-efficient valinamide fungicides, based on the structuralcharacteristics of iprovalicarb, according to substructure linking method and me-too method, wesynthesized a series of valinamide derivatives using L-valine and various amines and acid chloride asmaterial, of which20derivatives were first studied. The structures of these compounds were confirmedby IR,1H NMR, and HRMS.The preliminary biological activities of the target compounds were tested, and the result showedthat all compounds showed different inhibitory activities against Phytophthora spp includingPhytophthora capsici, Peronophythora litchi, Phytophthora melonis, Phytophthora nicotianae at theconcentration of50mg/L.The compounds of series Ⅲ exhibited excellent fungicidal activity, somecompounds had the same rate of inhibition as the positive control iprovalicarb, especially compounds3iand3j exhibited anti-oomycete activity against Phytophthora capsici with EC50value of1mg/L. Plantgrowth regulation activity screening showed some compounds also had high plant growth regulationactivity against monocots and dicots. Compound3e showed79%inhibition rate at the concentration of50mg/L against Cucumis sativus L.These new compounds can be used as the second lead compounds for discovery of new pesticidesin order to get highly effective pesticides by chemical structure modifications.