Quizalofop-p-ethyl intermediate impurity and preparation method thereof

The invention relates to quizalofop-p-ethyl intermediate impurities and a preparation method thereof, and belongs to the technical field of organic synthesis. According to the invention, N-(4-chloro-2-nitrophenyl)-3-oxobutanamide and diketene are used as raw materials, and the impurity 5-acetyl-1-(4-chloro-2-nitro-phenyl)-6-hydroxy-4-methyl-1H-pyridine-2-ketone is synthesized under the catalysis of a catalyst. According to the method disclosed by the invention, the N-(4-chloro-2-nitrophenyl)-3-oxobutanamide intermediate impurity is prepared, so that a qualified reference substance is provided for quality control of N-(4-chloro-2-nitrophenyl)-3-oxobutanamide, and the quality standard of the intermediate N-(4-chloro-2-nitrophenyl)-3-oxobutanamide is further improved; and meanwhile, important guiding significance is provided for research on by-products generated in the subsequent application reaction of the N-(4-chloro-2-nitrophenyl)-3-oxobutanamide. 本发明涉及一种精喹禾灵中间体杂质及其制备方法，属于有机合成的技术领域。本发明以N-(4-氯-2-硝基苯基)-3-氧代丁酰胺和