Synthesis and Fungicidal Activities of Novel Bis(trifluoromethyl)phenyl-Based Strobilurins

Strobilurins have become one of the most important classes of agricultural fungicides. To search for novel strobilurin compounds with unique biological activities, novel bis(trifluoromethyl)phenyl-based strobilurin analogues were synthesized by the reaction of 1-bis(trifluoromethyl)phenyl based methanone oxime with corresponding strobilurin pharmacophores in the presence of bases such as potassium hydroxide, potassium carbonate, or sodium hydride. ( E)-Methyl 2-(2-(((( Z)(1-(3,5-bis(trifluoromethyl) phenyl)-1-methoxymethylidene)amino)oxy)methyl)phenyl)-3-methoxyacrylate and ( Z)-methyl- N-( E)-2-(( E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(methoxyimino)methyl)benzyloxy-3,5-bis(trifluoromethyl)benzimidate were more effective against Erysiphe graminis and sphaerotheca fuligine than commercial strobilurin fungicides metominostrobin, azoxystrobin, and trifloxystrobin.