Synthesis And Fungicidal Activity Of Cyclohexene Ketoamines

In order to find a compound with a higher fungicidal activity, this paper have been designed and synthesised 50 enaminones compounds, and tested the fungicidal activity against eight kinds of plant pathogens by bioassay method, such as Botrytis cinerea. In vitro, most of these compounds had good fungicidal activity against Botrytis cinerea and Rhizoctonia solani. Especially compound J46, J47 and J48 had good fungicidal activity to most pathogens. These studies provided a theoretical basis for further exploration synthesis and fungicidal activity about enaminones compounds.LiHSO₄/SiO₂ as catalyst system, this paper used fifty kinds of teramines with different substituents and dimedone synthesized 50 enaminones compounds, and their structures were confirmed by IR and 1H NMR and GC-MS.The fungicidal activity both in vitro and in vivo were tested by bioassay method. Firstly, the fungicidal activity of the fifty substituted enaminone compounds （50 μg/mL） to eight kinds of plant pathogens were tested based on the method of mycelium growth rate. Then the compounds whose fungicidal activity was higher than 50% in preliminary bioassay were tested to determine the EC50 values. In vitro, the results showed that most of compounds had higher fungicidal activity against Rhizoctonia solani and Botrytis cinerea at 50 μg/mL. In vitro, there were 24 compounds with high fungicidal activity to Botrytis cinerea. The inhibition rate of compound J43 and J47 were 95.7% and 94.9% respectively. The inhibition rates of 21 compounds to Rhizoctonia solani were bigger than 50%, and compound J47 had the highest activity, rate was 97.2%. The inhibition rates of 10 compounds to Piricularia oryzae were bigger than 50% and the inhibition rate of compound J50 was 51.2%. Then EC50 values of the compounds with inhibition rate more than 50% in the preliminary bioassay were tested. In vitro, the compounds all had good fungicidal activity. We found that the EC50 values of the compounds of J37, J43, J44, J46, J47, J48, J49 and J50 were better than the pyrimethanil and procymidone against Botrytis cinerea.The EC50 values of J43, J47 and J48 were 6.6712 μg/mL,7.5736 μg/mL and 9.0672 μg/mL respectively. We also found that the compound J47 had high fungicidal activity with an EC50 value of 11.9633 μg/mL, compare with control carbendazim fairly. And EC50 values of J46 and J48 were 13.1403 μg/mL and 12.2637 μg/mL, a little larger than the control carbendazim.Most of those compounds had higher control efficacy than pyrimethanil and procymidone against Botrytis cinerea in vivo. Especially the compounds J47, J48 and J49, and their control efficacy were 93.6%,92.9% and 90.4% respectively. And the control efficacy of J47 was up to 86.3% against Piricularia oryzae. The control efficacy against Rhizoctonia solani of J48 was the highest. It was 85.9%.This paper studied the synthesis and fungicidal activity to Rhizoctonia solani and Botrytis cinerea of enaminones compounds, selected some compounds with high fungicidal activity such as J48 and J47, and set a foundation for further study.