The Study on the Design, Synthesis and Structure-activity Relationship of Insect Chitin Inhibitors Benzoylurea Derivatives Containing5-aminothiazole Cycle
|School||Hunan Normal University|
|Keywords||benzoylurea 5-aminothiazole synthesis|
Benzoylurea insecticide can inhibit the biosynthesis of insect chitin, kill the insect by making the larvae unable molted or its body fluid exudated. The compounds have some advantages such as high insecticidal activities, not easy to produce antibody, harmless to human and livestock. Because of its high insecticidal, fungicidal and herbicidal activities, thiazoel derivatives have received much attentions from pesticide research workers in the discovery of new pesticide. In order to find new benzoylurea derivatives with high biological activities, using the active substructure splicing and bioisostere principle,5-aminothiazole ring core and arylformyl urea have been monhtaged,Twenty new benzoylurea compounds containing5-aminothiazole ring core have been designed and synthesized in this study. Their s tructures of all these new compounds have been confirmed by1H NMR,13C NMR, Infrared Spectrum and Mass Spectrometry. The b-ioactivity of all compounds are being tested.The target compounds were synthesized by the reaction of2-Methyl-4-phenyl-thiazol-5-ylamine with aryl benzoyl isocyanate. Using substituted benzoic acids as raw material, benzoyl isocyanate were synthesized by reacting oxalyl chloride with substituted benzamide, which have been synthesized through acylation and ammonolysis of substituted benzoic acids. All reaction conditions above have been explored.Through the study of the synthesis of2-Methyl-4-phenyl-thiazol-5-ylamine, the literature method, which the synthesis of2,4-disubstituted-5-aminothiazole derivatives based on the Ugi four-component reaction by Thompson in2008, have been optimized.The optimized reaction conditions as follows:in the vulcanizing cyclization process, the amount of Lawson reagent is1.2times the vulcanizing substrate, m-xylene is solvent, nitrogen protection and reflux for4h. In the second dealkylation process,12times TFA amount the substrate has been used at room temperature. After dealkylation, the dealkylatded5-aminothiazole has been purified by using20%hydrochloric acid, comparing to the column chromatography purification method in the Literature, this method has the same yield with the Literature, but it has advantages such as low cost, high efficiency. It makes the literature method to be more practical.