吡噁唑菌酮类似物的合成及杀菌活性OA

A series of novel oxazolidinedione derivatives(2-2-2-30)was designed and synthesized based on the structure of pyramoxadone,a 5-position pyridine analogue of famoxadone.The target compounds were characterized by means of 1H NMR,13C NMR and high-resolution mass spectrometry(HRMS).Their in vitro antifungal activities were evaluated against nine plant pathogenic fungi using the mycelial growth rate method,with famoxadone as a positive control.Preliminary screening at 50 mg/L revealed that most compounds exhibited moderate to excellent inhibitory activity,particularly against Rhizoctonia solani,Sclerotinia sclerotiorum,Botrytis cinerea,and Pyricularia grisea.Structure-activity relationship(SAR)analysis indicated that bulky groups such as tert-butyl and cyclohexyl are detrimental to the enhancement of antifungal activity,while fluorine-containing compounds generally exhibited en-hanced antifungal activity.Compounds 2-16(EC50=3.78 mg/L)and 2-26(EC50=1.61 mg/L)exhibited superior activity against R.solani compared to famoxadone(EC50=4.38 mg/L)and pyramoxadone(EC50=9.67 mg/L).In vivo protective efficacy assays demonstrated that compounds 2-13,2-16 and 2-18 provided 88.3%,89.5%and 81.7%control against cotton damping-off at 200 mg/L,respectively,significantly outperforming the positive control.Molecular docking and electrostatic surface map analysis revealed that the SAR of this class of compounds follows a pattern where the hydro-phobic skeleton determines the binding orientation,electrostatic complementarity determines the binding strength,and substituent fine-tuning determines the activity level.