Identification and Synthesis of Major Impurities Formed During the Synthesis of Trifloxystrobin and Kresoxim-methyl Fungicides

During process development of Trifloxystrobin and Kresoxim-methyl fungicides, two impurities were identified. These impurities were isolated and characterized using LCMS, IR, 1H NMR, 13C NMR and elemental analysis. Structures of the impurities were further unambiguously confirmed by their independent synthesis. Structure of both impurities revealed that they possess methyl (E)-methoxyiminoacetate pharmacophore, responsible for antifungal activities of strobilurins, in combination with arylmethyl (E)-methoxyiminoacetate framework.