Synthesis,Characterization And Biological Activities Of 1,2,4-Triazole Derivatives

1,2,4-Triazole derivatives having a broad spectrum of biological activities and efficient pharmacological activities are the important classes of nitrogen-containing heterocyclic compounds, which have played a prominent role in pesticide and medicine due to their superior selectivity, high activity and low toxicity. In order to screen out the lead compounds of triazoles with higher fungicidal activity, two series of the novel 1,2,4-triazole derivatives were designed and synthesized in this paper. Their structures were confirmed by 1H NMR,13C NMR, IR, HRMS, X-ray diffraction techniques and elemental analysis. The fungicidal activities of these compounds against four vegetable pathogens were preliminarily tested and the relationship between structure and activity was discussed.(1) The intermediate 4-amino-4,5-dihydro-3-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-1,2,4-triazole-5-thione was synthesized by acetylacetone and hydrazine hydrate as starting materials via cyclization, substitution and hydrazinolysis. Then twenty-five novel Schiff bases were synthesized from the intermediate and substituted benzaldehydes. These compounds were characterized and tested for the fungicidal activities against four vegetable pathogens containing Pythium solani, Gibberlla saubinetii, Gibberll nicotiancola and Fusarium oxysporium f.sp. niveum. Results indicated that some of the compounds have better fungicidal activities comparing with triadimefon.(2) Fifteen novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole derivatives containing pyrazole rings were synthesized by the reaction of 4-amino-4,5-dihydro-3-((3,5-dimethy1-1H-pyrazol-1-yl)methyl)-1,2,4-triazole-5-thione and substituted benzoic acids in POCl3. After these compounds were purified and characterized, preliminary fungicidal activities were tested in vitro. The results showed that some of the compounds exhibit relatively good fungicidal activities.