Synthesis And Process Research Of Propiflufenic Acid And Its Derivatives

As a member of the chemical family of N-phenylphthalimides,flumioxazin was invented by Japan's sumitomo chemical industry co,LTD.It is widely used as an effective herbicide with high efficiency,low toxicity,good selectivity,safety to non-target organisms and less pollution to the environment,etc.In order to find new potential herbicide candidates with better activities and environmentally friendly properties,we designed 13 new related compounds derived from the structures of flumioxazin.The synthesis of flumioxazin and its derivatives are investigated in detail in this paper.First,we designed four schemes to synthesize the important intermediate 7-Fluoro-6-amino-2H-1,4-benzoxazin-3(4H)-one and two schemes for flumioxazin and its derivatives.An optimal scheme is obtained based on the experimental results:the starting material 2,4-difluoronitrobenzene is etherified,reduced,nitrated and reduced to get the intermediate 7-Fluoro-6-amino-2H-1,4-benzoxazin-3(4H)-one,the followed aminolysis and condensation reactions of which could produce the target compounds.The products purities from this reaction route are higher than 98%and the yields more than 53.3%.The reaction conditions are also mild for control and environmentally safe,with low cost and good operability,which is suitable for large scale production.The paper also investigated the effect of different reaction factors such as the solvent,acid capturer,the reaction temperature,reaction time,material ratio and catalyst etc.,on the reactions.The optimal reaction conditions are obtained based on a large number of single factor experiments.The analysis methods by HPLC of the target products and intermediates are also established.All the structures of target products and their intermediates are characterized and confirmed by 1H NMR,IR,HPLC,elemental analysis and melting point determination.