Study On Synthesis And Insecticidal Activity Of 3-(3,4-methylenedioxy-6-alkoxy) Acrylamide Compounds

In the process of creating efficient, low toxicity, environmentally friendly pesticides, plant pesticides become a focus of exploiting new pesticides with their own unique advantages, so it becomes an important way of producing new pesticides to find new active substances from the natural plant substances or to be modeled after known natural products with activity and to introduce known active groups or substructure through structural modification, thereby increasing the level of activity, and selecting new pesticides with better capability than natural active substances .Natural product, fagaramide has significant activity, and because of its simple structure, great transformation potential, so it is possible to become a natural products model for pesticide synthesis research. Fagaramide has a structure of acrylamide, while acrylamide compounds have been widely used in industry, medicine, pesticide and other fields.This paper is based on the above ideas,trying to synthetise new pesticides with the natural acrylamide compound-fagaramide as a model. Three intermediate products of 4a, 4b, 4c were synthesized with sesamol as raw material, followed by etherification, vilsmeier reaction, wittig-horner reaction and hydrolysis, and the overall yield is 64.4 %. Then 26 title compounds were synthesized from the parent compounds, 4a, 4b, 4c, of which 23 compounds have not been reported. The structures of all the compounds were confirmed by IR, MS, 1~H NMR and (13)~C NMR.Using leaf immersion, the insecticidal activity of 26 target compounds at the concentration of 150 mg/L against the third instar larvae of Mythimna separate were determined, compared with imidacloprid as a positive control. The results showed that 26 target compounds have certain insecticidal activity with mortality of 6.7 % ~ 66.7 % to Mythimna separate. Compounds 5b-7, 5b-8, 5c-3 and 5c-5 had better insecticidal activity, their mortality reached 50.0 %, 50.0 %, 53.3 % and 66.7 %.These results provide a basis for the further studies of QSAR and structures transformation of acrylamide compounds.