Synthesis And Fungicidal Activity Of Benzimidazole Derivatives Containing Pyrimidine Thioether/Thioacetamide Moiety

Benzimidazole derivatives have been the focus in the field of medicine and pesticide research at home and abroad due to the advantage of high systemic, high systemic, high bioactivity, low toxicity, etc. Pyrimidine is another important heterocyclic compound and has a broad range of applications in the fields of biology, medicine and pesticide due to their physiological activity and reactivity characteristics. Furthermore, as the fungicide, herbicide and pesticide, amide has been developed for many years and always been the focus on the study of novel pharmaceuticals. Therefore, the research of amide has always drawn much attention in the field of pesticide and medicine.In order to find highly active pesticide varieties, pyrimidine and acid amide was introduced into benzimidazole matrix structure according to the active sub-structure connection in this paper. Two series benzimidazole derivatives were synthesized. The main work was summarized as follows:(1) The target compounds 2-(6-(4-fluorophenyl)-2-(methylthio)pyrimidin-4-yl)-1Hbenzimidazole(I) were synthesized starting from o-phenylenediamine, lactic acid, aromatic aldehyde, thiocarbamide and halohydrocarbon via the reaction of cyclization, oxidant,condensation, substitution.(2) The target compounds 2-(4-(1H-benzo[d]imidazol-2-yl)-6-(4-fluorophenyl)pyrimidin-2-yl) thioacetamide(II) were synthesized starting from 4-(1H-benzo[d]imidazol-2-yl)-6phenylpyrimidine-2-thiol, chloroactic and various amine. The structures of target compounds are shown as follows:(3) All the target compounds were confirmed by 1H NMR, IR and EA. Some experimental processes were improved. The synthetic condition characteristic absorption peaks of thetarget compounds were analyzed and discussed in details.(4) In this paper, the antifungal activity of the target compounds aginst Botrytis cinerea and Sclerotinia sclerotiorum were tested by the mycelium growth rate method. The results show that, the two series compounds(I, II) have certain inhibition against Botrytis cinerea and Sclerotinia sclerotiorum. Compared with the control(carbendazim), the acticity of the target compounds Ia, Ii, IIn, IIt were better than carbendazim against Botrytis cinerea. The EC50 values of Ia, Ii, IIn, IIt were 0.13, 0.14, 0.13, 0.15 μg/mL, which were all less than that of carbendazim(0.21 μg/mL). Furthermore, the activity of the target compounds Ii, Ih, IIj, IIu were better than carbendazim against Sclerotinia sclerotiorum. The EC50 values of Ii, Ih, IIj,IIu were 4.65, 6.72, 5.61, 6.12 μg/m L, which were all less than that of carbendazim(13.32μg/mL).