Design, synthesis and SAR study of novel sulfonylurea derivatives containing arylpyrimidine moieties as potential anti-phytopathogenic fungal agents

Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy.The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities.Based on the preliminary fungicidal activities,a CoMFA model was constructed and the 3 D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities.In order to study interaction mechanism,10 k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities.It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS.Thus,the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphyt o pathogenic fungal agents.

Synthesis and Antifungal Activities of New Type β-Methoxyacrylate-Based StrobUurin Analogues

Strobilurins have become one of the most important classes of agricultural fungicides. To discover new strobilurin derivatives with high activity against resistant pathogens, a series of novel fl-methoxyacrylate analogues were designed and synthesized by integrating substituted pyrimidine with a strobilurin pharmacophore. The compounds were confirmed and characterized by infrared, 1H nuclear magnetic resonance, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds 1 exhibited potent antifungal activity against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at the concentration of 50 μg/mL. Exhilaratingly, compound 1 a （R= methyl） showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.

Synthesis and Evaluation of Novel N-（4＇-Arylpyrimidin-2＇-yl） Sulfonylurea Derivatives as Potential Antifungal Agents

Sulfonylureas（SUs） are potent and selective inhibitors of acetohydroxyacid synthase and has been used as herbicides. Some SUs also displayed other biological activities. In order to discuss the antifungal activity of SUs, a series of novel SUs containing aryl-substituted pyrimidine moieties was designed and synthesized. The preliminary bioassay showed that the title compounds exhibited moderate to favorable fungicidal activities in vivo. Especially, compound 9b exhibited more efficacy than the controls against five fungi at 25 mg/L. These promising results indicate that an aryl group on pyrimidine ring is favorable for antifungal activity and SUs are potential inhibitors for some phytopathogenic fungi.