Optimization On The Synthesis And Process Of Fluoxastrobin

Fluoxastrobin was developed by Bayer as a new strobilurins fungicide,which is used to protect the stems and leaves of plants.Strobilurin derivatives have become one of the most important classes of agricultural fungicide due to a novel action mode,wide fungicidal spectrum,lower toxicity toward mammalian cells,and environmentally benign characteristies.Domestic study on the fluoxastrobin is still very few now,so the further reaserh towards it may be great practical significant.The synthetic route of fluoxastrobin are reviewed,with the advantages and disadvantages conditions are compared here,the optimal method for the preparation of fluoxastrobin with the best route of industrialization was carefully investigated.The key intermediates(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone o-methyl oxime and 4,5,6-trifluoro pyrimidine were synthesized separately with 2-Hydroxyphenylacetic acid methyl ester and diethyl malonate as starting materials through five steps.And then,the final target product-fluoxastrobin was synthesized through another two steps.The effect of catalyst,solvent,molar ration,feeding method and temperature have been carefully investigated.Meanwhile,each important intermediate compound and the target product were all characterized by GC,HPLC,IR,NMR and MS.Under the optimized process condition,the yield of(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime is 25.0%(2-Hydroxyphenylacetic acid methyl ester),with the purity of 98.5%;The yield of 4,5,6-trifluoropyrimidine is 39.5%(base on diethyl malonate),with the purity of 95.1%.The total yield of fluoxastrobin is 22.5%(base on 2-Hydroxyphenylacetic acid methyl ester),with the purity of 98.5%.This synthetic route is simple and suitable for industrialized production with cheap available material,simple operation,high security and high yield.