Chemical Modification And Bioactivities Of Nitrogenous Heterocyclic Compounds Fipronil And Hexahydropyridazine

Agriculture is the foundation underlying all efforts to build our country.To ensure a population of 1.3 billion’s foodstuff safty is a major well-being issue.Undoubtedly,lifting food yield is one of the most essential way to relieve food crisis.But now crop diseases,insect pests and weeds are almost worldwidely,which influence food production.It is urgent for chemists to develop more highly-effective pesticides which are safe to human-beings,environment and non-target objects.In this thesis,with nitrogenous heterocyclic compounds fipronil(Ⅰ) and hexahydropyridazine(Ⅱ) as leading compounds.Thirteen novel fipronil phosphorothioate derivatives were synthesized starting from 5-amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-3-cyanopyrazole-4-disul fide(Ⅲ) which is intermediate of the synthesis of fipronil via reduction and phosphoration.Hexahydropyridazine-1-carboxamide derivatives(Ⅴ) were synthesized starting from hexahydropyridazine and substituted isocyanate (Ⅳ),three kinds of thirteen novel hexahydropyridazine derivatives were synthesized by transforming substituent group on phenyl、N-acyl and cyclization.The crystal structures of three hexahydropyridazine derivatives: N-(3-(trifluoromethyl)phenyl) piperazine-1-carboxamide(Ⅵ),2-acetyl-N -(3-(trifluoromethyl)phenyl)piperazine-1-carboxamide(Ⅶ) and 2-[3-(trifluo romethyl)phenyl]perhydro-1,2,4-triazolo[1,2-a]pyridazine-1,3-dione(Ⅷ) were determined by X-ray diffraction analysis.Preliminary bioassays showed that thirteen novel fipronil phosphorothioate derivatives exhibited 100%lethal efficiency against Culex pipidens pallens at 50 mg/L;some of the hexahydropyridazine derivatives have herbicidal activities.Collect thirty-five compounds which have activities against aphid, pharmacophore model was generated by Catalyst 4.10 to assess structure characteristics of fipronil phosphorothioate derivatives which have no activity against aphid,then to instruct modification of high activity compounds.