Fluoxastrobin is a strobilurin-type fungicidal active ingredient used for controlling fungal diseases such as early blight, late blight, leaf spots, leaf rust, and Rhizoctonia solani. Fluoxastrobin has been registered for foliar use on peanuts, tuberous and corm vegetables, leaf petiole vegetables, fruiting vegetables, and turf, as well as seed treatment for potato, peanuts, and turf. Turf applications are labeled for professional pest control operators.
Bayer provides a number of synthetic pathways to fluoxastrobin, although all proceed through a consecutive reaction of 4,6-dichloro-5-fluoro-pyrimidine with 2-chlorophenol and (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (4) as described in U.S. Pat. No. 6,734,304 and shown below:

(E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (4) is an important intermediate in the synthesis of fluoxastrobin. However, known methods of synthesis of (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime are low yielding, include toxic reagents, and require lengthy and tedious work-up techniques and procedures, such as recrystallization and chromatography, which increase fluoxastrobin industrial production costs. Thus, there remains a need for a cost-efficient process of making (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime.
USPTO Backgrounds
USPTO Backgrounds