Study On Benzoxazinones Fluorescent Materials

In recent several decades,most reports on benzoxazinones have focused on biopharmaceuticals,insecticides,and herbicides.In this paper,we designed and synthesized several benzoxazinone derivatives as fluorescent materials and measured their optical performance.The main contents of the thesis include:（1）By using methyl 3,4,5-trimethoxybenzoate as the starting material,the intermediate compound 2-amino-3,4,5-trimethoxybenzoic acid was synthesized by nitration,hydrolysis and reduction reaction in,the yield 45%,70%and 61%,respectively.The overall yield of the final product was 19%.（2）Compound 2-amino-3,4,5-trimethoxybenzoic acid used in the substitution reaction with different phenylsulfonyl chloride including p-toluenesulfonyl chloride,p-chlorophenylsulfonyl chloride,and p-fluorophenylsulfonyl chloride to produce the corresponding phenylsulfonamide derivatives.The later underwent,dehydration and cyclization reaction in pyridine to form benzoxazinone product.By this protocol three new target fluorescent compounds were prepared,including 6,7,8-trimethoxy-2-[3,4,5-trimethoxy-2-（4-methylphenylsulfonamido）]phenyl-4-benzoxazinone,6,7,8-trimethoxy-2-[3,4,5-trimethoxy-2-（4-chlorophenylsulfonamid-o）]phenyl-4-benz eneoxa-zinones,and6,7,8-trimethoxy-2-[3,4,5-trimethoxy-2-（4-fluorophenylsulfonamido）]phenyl-4-benzoxazinone in,the yield:30%,35%,and 32%,respectively.Dehydrocyclization of 2-amino-3,4,5-trimethoxybenzoic acid with p-chlorobenzoyl chloride in pyridine afforded a new fluorescent compound6,7,8-trimethoxy-2-（4-chlorophenyl）phenyl-4-benzoxazinone in 71%yield.（3）The structure of the synthesized benzoxazinone fluorescent compounds was characterized by ¹H NMR,¹³C NMR,FT-IR and MS.（4）We have tested the optical properties of four synthetic fluorescent materials,It includes fluorescence emission spectra and ultraviolet absorption spectra under different concentration gradients.The solution was exposed to ultraviolet light for 0 h,0.5 h,1 h,2 h and 4 h respectively,then the fluorescence emission spectrum and ultraviolet absorption spectrum were measured.It was found that the fluorescence intensity of the solution did not change significantly after UV irradiation,and had good photostability.But with the passage of time,the intensity of the fluorescence of the four fluorescent compounds will decay to varying degrees.