Preparation method of flumioxazin intermediate

The invention relates to the field of pesticides, and discloses a preparation method of a flumioxazin intermediate. The preparation method of the flumioxazin intermediate comprises the following steps: sequentially carrying out reduction reaction, amidation reaction, esterification reaction, hydrolysis reaction and ring closing reaction on 2, 4-difluoronitrobenzene to obtain 7-fluoro-2H-benzo [b] [1, 4] oxazine-3 (4H) ketone. According to the preparation method of the flumioxazin intermediate, the 2, 4-difluoronitrobenzene which is low in price is adopted as a raw material, the target product is prepared through five-step reaction, the yield is high, aftertreatment is simple and convenient, and the solvent can be recycled, so that the cost of the raw material is reduced. 本发明涉及农药领域，公开了一种丙炔氟草胺中间体的制备方法。本发明的丙炔氟草胺中间体的制备方法包括：使2,4-二氟硝基苯依次进行还原反应、酰胺化反应、酯化反应、水解反应和合环反应得到7-氟-2H-苯并[b][1,4]噁嗪-3(4H)酮。根据本发明的丙炔氟草胺中间体的制备方法，其采用价格低廉的2,4-二氟硝基苯为原料，经五步反应制得目标物，收率高、后处理简便，溶剂能够重复利用从而降低了原料成本。