Studies On The Synthesis And Fungicidal Activity Of Novel Imidazole Derivatives

Heterocyclic compounds widely exist in the nature with widespread biological activities, which attract scientists's interests significantly. Imidazole derivatives are one of the important families in heterocyclic compounds, and many of them have recently been used in medicine and pesticide fields. Therefore, chemists and pharmacists pay more attentions to design and synthesize this kind of compounds.According to the isostere and the connecting priciple of active subunit groups, we designed a kind of 8-methyl-2H-imidazo [1, 5-d] [1, 2, 4] triazin-1-one derivatives. In the synthesizing process, another kind of N-cyano-5-methyl-lH-imidazole-4-carboxamide derivatives was discovered accidently. Finally, two series of thirty two novel imidazole derivatives were synthesized. Their structures were characterized by ¹H NMR, MS and element quantitative analysis. The biological activities of the newly compounds were also studied, many of them showed good fungicidal activity in vetro. It's summarized as follow:In the first series, sixteen 8-methyl-2H-imidazo [1, 5-d] [1, 2, 4] triazin-1-one derivatives were synthesized. Part of them showed good inhibition to Rhizoctonia solani, Botrytis cinereapers and Colletotrichum gossypii bacterium under the concentration of 50μg/mL. The inhibitory rate was up to 80%. LJ3, LJ9, LJ10 and LJ12 showed high activity to Colletotrichum gossypii bacteria with the inhibitory rate beyond 90%. LJ4, LJ13, LJ14, LJ15 and LJ16 inhibited both Rhizoctonia solani and Botrytis cinereapers.In the second series, sixteen N-cyano-5-methyl-1H-imidazole-4-carboxamide derivatives were synthesized. All of them showed high activity to Rhizoctonia solani bacteria. So we went further testing of EC50. The values of EC₅₀ were between 2.63μg/mL～31.32μg/mL. CN1, CN3～CN8 and CN13～CN16 were below 10μg/mL, CN8 was the lowest one, 2.63μg/mL.We studied on the synthesis of 8-methylimidazo[1,5-d][1,2,4]triazin-1(2H)-one, which was the key intermediate in the reaction, and optimized the solvents, ratio of materials, catalyst, the dosage of catalyst, heating manner and after-dealing manner.We first discovered a novel method of preparating N-cyano carboxamide compounds.