Discovery of flufenoxystrobin: Novel fluorine-containing strobilurin fungicide and acaricide

• Published in: Journal of fluorine chemistry 2016-05, Vol.185, p.173-180
• Main Authors: Li, Lin, Li, Miao, Chi, Huiwei, Yang, Jichun, Li, Zhinian, Liu, Changling
• Format: Article
• Language: English
• Subjects: Acaricidal activity; Derivatives; Equivalence; Erysiphe graminis; Flufenoxystrobin; Fungicidal activity; Fungicides; Greenhouses; Infrared radiation; Intermediate derivatization methods; Mammals; Nuclear magnetic resonance; Strobilurin derivatives; Structure-activity relationship; Toxicology; Triticum aestivum
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2016.03.013

2-Chloro-4-(trifluoromethyl)phenol, by-product in synthesis process of oxyfluorfen, was employed as the starting materials to achieve compound 2a (SYP-3759, flufenoxystrobin) with excellent activity against Erysiphe graminis and acaricidal activity against Tetranychus cinnabarinus. Trifluoromethyl group on 4-position of substituted phenyl plays an important role in enhancing the biological activity of target compounds. [Display omitted] •Application of the strategies of intermediate derivatization method.•Trifluoromethyl, a very strong electron withdrawing group, plays an important role on fungicidal activity.•Characterization of target compounds using 1H NMR, 19F NMR, IR and elemental analysis.•Excellent fungicidal activity against Erysiphe graminis and acaricidal activity against Tetranychus cinnabarinus.•Detailed structure and activity relationship of target compounds. To discover new strobilurin analogues with high activity, a series of new fluorine-containing strobilurin derivatives were synthesized utilizing intermediate derivatization methods (IDM). The compounds were identified by 1H and 19F nuclear magnetic resonance (NMR), IR and elemental analysis. Preliminary bioassays in greenhouse indicated that compounds 2a (SYP-3759, flufenoxystrobin) and 2c exhibited excellent fungicidal activities against Erysiphe graminis protecting wheat at 1.56mgL−1 concentration and compounds 2a showed a moderately high acaricidal activity at 10mgL−1. Field trials showed the fungicidal activities of compounds 2a and 2c is almost equivalent to that of pyraclostrobin, higher than that of triadimefon and the acaricidal activity of compound 2a is almost equivalent to that of pyidaben, but lower than that of fluacrypyrim. The preliminary mammalian toxicology results showed compound 2a was a low-toxicity compound. In conclusion compound 2a is a promising candidate for further development; mammalian toxicology and ecotoxicology with compound 2a are in progress.