Synthesis, Insecticidal And Fungicidal Activities Of Substituted Pyrazole Derivatives

Pyrazol derivatives is a hot on the research and development about new pesticide. In this paper, 26 5-amino pyrizol derivatives and 16 substituted aminopropyl isothiocyanates derivatives were synthesized via conjugated pyrazol ring with isothiocyanates group based on the theory of bioisosterism. All compounds were characterized by 1H NMR, 13 C NMR, HSQC, HMBC and HR-ESI-MS. The insecticidal activities against third instar larvae of Plutella xylostella Linnaeus and fungicidal activities against Botrytis cinerea, Rhizoctonia solani Kuhn, Valsa mali Miyabe et Yamada, Thanatephorus cucumeris(Frank) Donk, Fusarium oxysporum(S-chl) f.sp.cucumerinum Owen and Fusarium graminearum Schw were tested by Insect body and leaf immersion method and growth rate method, respectively. Through the analysis of structure-activity relationship, the main results are as follows:1. The moiety of isocyanates were introduced to pyrazole ring to form 26 5-amino pyrizol and 16 substituted aminopropyl isothiocyanates derivatives. Query by CA system, 41 compounds were new.2. Used insect body and leaf immersion method to test the insecticidal activities against third instar larvae of Plutella xylostella Linnaeus of 42 substituted pyrazole derivatives. 16 kinds of substituted aminopropyl isothiocyanates showed higher insecticidal activities than 5-amino pyrizol derivatives at the concentration of 1000 μg/mL, the emendation death rate were 38.6~86.3%. Among the 26 kinds of 5-amino pyrizol derivatives, compound 26 showed the highest activities, the emendation death rate was 74.8% at concentration of 1000 μg/mL, the others exhibited lower bioactivities.3. The fungicidal activities of 42 substituted pyrazole derivatives against Botrytis cinerea, Rhizoctonia solani Kuhn, Valsa mali Miyabe et Yamada, Thanatephorus cucumeris(Frank) Donk, Fusarium oxysporum(S-chl) f.sp.cucumerinum Owen and Fusarium graminearum Schw were evaluated through growth rate method. The result of bioassay indicated that both 5-amino pyrizol derivatives and substituted aminopropyl isothiocyanates possessed fungicidal activities. Generally, substituted aminopropyl isothiocyanates exhibited higher activities. Compound 26 showed the highest activities against such 6 kinds of tested phytopathogen.4. It could be found that the insecticidal activities of 5-amino pyrizol derivatives could be improved by introduced of isothiocyanates group, and substituted phenyl on R3 position showed more effectives than carboxyl moiety.5. Through the analysis of structure-activity relationship, when introduced halogen atom, especial cholorine, fluorine atom, and cyano group, the fungicidal activities of tested compounds could be improved. When halogen and cyano group were both introduced, the fungicidal activities were developed dramatically. Isothiocyanonate group also could increase the acitivities of substituted pyrazoles.6. Compound 26 not only showed insecticidal activities against third instar larvae of Plutella xylostella Linnaeus but also exhibited excellent fungicidal activities against 6 tested phathogen. It has the potential to further research and development.