Design, Synthesis And Biological Activity Of 3(2H)-Pyridazinone Derivates

Along with human paying more attention to environments protection and showing the disadvantage of the traditional insecticides, Insect growth regulators (IGRs) with high potency, good selectivity and pleasant safety to environment and non-target organism, are regarded as 'the perfect compounds friendly to environment', 'the ideal pesticides in 21st century' and 'novel insect regulators'. Because of playing an important role of IGRs in Integrated Pest Management system, it becomes necessary to develop new IGRs to meet the needs of controlling pests in sustainable agriculture.In this thesis, two types of 3(2H)-pyridazinone derivates were designed by the method of linking active sub-structures of chrysanthemate ester or novel nicotinic heterocycle groups with 3(2H)-pyridazinone. Nineteen new compounds were synthesized in 5-6 steps with the starting material of 2,3-Dichloro-4-oxo-but-2-enoic acid. Their synthetic methods were mainly studied in this paper. Their structures were confirmed by 'H-NMR, IR and elemental analysis, and their spectra were also analysized. The synthesis methods of two pyridazinone intermediates [5-(2-Bromo-ethoxy)-2-tert-butyl-4-chloro-2H-pyridazin-3-one and 5-(2-hydroxy-ethoxy)-2-tert-Butyl-4-chloro-2H-pyridazin-3-one] were disscussed. The reaction activity of different heterocycles and 5-(2-bromo-ethoxy)-4-chloro -2H-pyridazin-3-one were also studied.In the preliminary bioassay test, most compounds have been showed growth inhibition against houseflies (Musea domestica Linnaeus), cotton boll worm(Helicoverpa armigera Hubner), red flour beetles (Tribolium castaneum Herbst) and asiatic locust(Locusta migratoria manilensis Linne)in the concentration of 500mg/L. The compounds of Y3-1, Y3-3, Y3-12, Y3-14 and Y3-15 inhibited the growth of housefly second larval, the mortality rates were 65.0%, 70.0%, 77.5%, 62.5% and 62.5%, respectively. The mortality of tebufenozide was 72.5%. Some compounds of type II showed good biological activity, inhibited growth of locust third larval. The mortality rates (growth inhibition rates) of Y3-4, Y3-6, Y3-8, Y3-9 and flufenoxuron were 75.0%(90.0%), 75.0%(95.0%), 75.0%(80.0%), 75.0%(95.0%), 85.0%(90.0%) after 120 hour.