In this study, 32 novel quinazolinone-scaffold-containing pyrazole carbamide derivatives were designed and synthesized in a search for a novel fungicide against Rhizoctonia solani. Single-crystal X-ray diffraction of 3-(difluoromethyl)-N-(2-((6,7-difluoro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-1-methyl-1H-pyrazole-4-carboxamide (6a11) confirmed the structure of the target compounds. The in vitro antifungal activity of the target compounds against R. solani was evaluated at 100 µg/mL. The structure-activity relationship analysis results revealed that antifungal activity was highest when the substitution activity was at position 6. Moreover, the position and number of chlorine atoms directly affected the antifungal activity. Further in vitro bioassays revealed that 6a16 (EC50 = 9.06 mg/L) had excellent antifungal activity against R. solani that was higher than that of the commercial fungicide fluconazole (EC50 = 12.29 mg/L) but lower than that of bixafen (EC50 = 0.34 mg/L). Scanning electron microscopy), 7.33 (SEM) revealed that N-(2-((6,8-dichloro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (6a16) also affected the mycelial morphology. The findings revealed that molecular hybridization was an effective tool for designing antifungal candidates. Meanwhile, pyrazolecarbamide derivatives bearing a quinazolinone fragment exhibited potential antifungal activity against R. solani.

中文翻译：

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含有吡唑脲衍生物作为抗真菌剂的新型喹唑啉酮支架的设计、合成和生物活性。

在这项研究中，设计并合成了 32 种新型含喹唑啉酮支架的吡唑脲衍生物，以寻找一种新型的抗立枯丝核菌的杀菌剂。3-(二氟甲基)-N-(2-((6,7-二氟-4-氧代喹唑啉-3(4H)-基)甲基)苯基)-1-甲基-1H-吡唑的单晶X射线衍射-4-甲酰胺(6a11)证实了目标化合物的结构。在 100 µg/mL 下评估目标化合物对 R. solani 的体外抗真菌活性。构效关系分析结果表明，取代活性在6位时抗真菌活性最高。此外，氯原子的位置和数量直接影响抗真菌活性。进一步的体外生物测定显示 6a16 (EC50 = 9.06 mg/L) 对 R. solani 高于商业杀菌剂氟康唑 (EC50 = 12.29 mg/L) 但低于 bixafen (EC50 = 0.34 mg/L)。扫描电子显微镜），7.33（SEM）显示 N-(2-((6,8-二氯-4-氧代喹唑啉-3(4H)-基)甲基)苯基)-3-(二氟甲基)-1-甲基- 1H-pyrazole-4-carboxamide (6a16) 也影响菌丝形态。研究结果表明，分子杂交是设计抗真菌候选药物的有效工具。同时，带有喹唑啉酮片段的吡唑脲衍生物对立枯病菌表现出潜在的抗真菌活性。8-dichloro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (6a16) 也影响菌丝形态。研究结果表明，分子杂交是设计抗真菌候选药物的有效工具。同时，带有喹唑啉酮片段的吡唑脲衍生物对立枯病菌表现出潜在的抗真菌活性。8-dichloro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (6a16) 也影响菌丝形态。研究结果表明，分子杂交是设计抗真菌候选药物的有效工具。同时，带有喹唑啉酮片段的吡唑脲衍生物对立枯病菌表现出潜在的抗真菌活性。