Study On The Synthesis Process Of A New Type Of Chlorofluoropyridine Herbicide

Florpyrauxifen is a novel aryl carbamate herbicide developed by Dow Agro Sciences.The herbicides have good conductivity and absorption,have a wide range of herbicidal spectrum,fast onset,low cost and are not resistant to resistance.The update of herbicide varieties is the basic requirement for maintaining the long-lasting chemical herbicides,and it is also a prerequisite for the continuous enhancement and improvement of herbicides.Therefore,it is necessary to synthesize more kinds of herbicides to promote development.In this work,certain groups of florpyrauxifen herbicides have been altered to provide novel herbicides.The preparation uses trifluoroacetic acid and p-methoxyaniline as raw materials to prepare trifluoromethoxyphenylimine.trifluoromethoxyphenylimine to prepare alkynylimine by Sonogashira coupling reaction.The alkynylimine is reacted with p-chlorobenzylamine in a tetrahydrofuran solution to obtain a pyridine derivative.Finally,the pyridine derivative is subjected to deprotection and chlorination to obtain the target product,methyl 4-amino-3-chloro-6(4-chlorophenyl)-5-fluoropicolinate.In addition,A benzyl group is introduced on the basis of the synthesis of methyl 4-amino-3-chloro-6(4-chlorophenyl)-5-fluoropicolinate.Trifluoromethoxyphenylimide is used as the raw material,and then subjected to Sonogashira coupling reaction,ring-closing reaction,deprotection and chlorination to obtain pyridyl formaldehyde.Pyridine formaldehyde is oxidized to picolinic acid under basic conditions.Finally,the pyridinecarboxylic acid and benzyl bromide were subjected to a substitution reaction to obtain the target product benzyl 4-amino-3-chloro-6-(4-chlorophenyl)-5-fluoropicolinate.The synthesized material was characterized and identified by nuclear magnetic resonance analysis.The synthetic route was optimized by orthogonal test and the ideal results were obtained.The reaction conditions of this route are simple,and the yield is 4% and 5% higher than those reported in the literature,which is of great significance for subsequent scale-up experiments and industrial large-scale production.In this work,3-Phenyl-N-[4-(10,15,20-triphenyl-porphyrin-5-yl)-phenyl]-acrylamide(TPPCA)was synthesized for the determination of metronidazole(MTZ).It was found that the type of fluorescence quenching was static quenching determined by Stern-Volmer plot and UV absorption spectroscopy,and thermodynamic related parameters were also obtained.Furthermore,the corresponding measurement conditions: the acidity of the system,the type of surfactant,the concentration of TPPCA and the sequence of reagent addition were optimized.Under the optimal experimental conditions,the linear range of MTZ was determined to be 0.01 to 0.20 ?g m L-1,and the limit of detection(LOD)was 0.004 ?g ml-1.Importantly,this report provides a simple,fast,and sensitive probe for the determination of MTZ in pharmaceutical practice.