Study On The Synthetic Process Of Pymetrozine And Its Analogues

Pesticide is an important auxiliary product for the base industry of our country.Neonicotinoid insecticide is a sort of fungicide with high efficiency, low toxicity, broadspectrum, highly selective and friengly to the environment. It has no cross resistance withother insecticide and can be degraded rapidly by microbes that became a new-typeinsecticide with market potential in our country. Recently, pymetrozine has beenconcerned with great research value as a novel insecticide. This dissertation is focused onthe synthetic methods of pymetrozine and its analogues.In the present paper, synthetic methods of pymetrozine were reviewd in detail. A newsynthetic route for industrial manufacture of pymetrozine was developed with the purposeof improvement on the disadvantages and a total yield of58.1%was obtained(Literature52.9%). Meanwhile the problems in each of the reaction and side reactions were studiedand discussed. In this process original material ethyl acetate reacted with hydrazinehydrate by the condensation(yield94%); and by the cyclisation reacted with triphosgenein1,2-dichloroethane(yield85%); then reacted with chloroacetone in acetone by thealkylation(yield95%); the next reacted with hydrazine hydrate in methanol by thecondensation(yield85%), finally pymetrozine was formed by the hydrolysis under acidiccondition and reacted with3-pyridinecarboxaldehyde by the condensation(yield90%).The purity of pymetrozine reached99.9%.In addition, pymetrozine is chosed as the lead compound, and two compounds werefirstly designed and synthesized. These compounds were characterized by introducingdifferent functional groups replace pyridine ring with the method of intermediatederivatization.The yield all above90%.The chemical structures of Pymetrozine and Pymetrozine analogues had beencharacterized by1H-NMR.