Synthesis Of Boronic Acid Intermediates For Luminescent Materials

Organic electroluminescent materials are usually prepared by Suzuki coupling reaction with boric acid as a base and a compound with bromine substitution.At present,the research on luminescent materials is sought after by more and more scientific researchers,while the research on boric acid substrates is relatively small,and there are related process routes that are not complete,the yield of synthetic products is low,and the economic benefits are poor.problem.Therefore,the study of boric acid intermediates for luminescent materials is also of great significance.Thiophene boronic acid and fluorene type boronic acids are currently more intermediates used in luminescent materials.Among thiophene luminescent materials,thiophene has unique optical properties and electron transport capabilities due to its high electron cloud density.Used in electroluminescent materials;in fluorene-based luminescent materials,the research mainly focuses on the modification of fluorene ring 2 carbon.This topic mainly studies thiophene boronic acid and boronic acid on fluorene ring 2 carbon;but currently thiophene It is difficult to synthesize boronic acids like fluorene and fluorene,and the existing synthetic process route is immature.In order to overcome the existing shortcomings,a better synthetic route was selected and designed.This subject was commissioned by a partner company to design and synthesize 1-dibenzothienylboronic acid(A)and B-[9,9-bis(4-methylphenyl)-9H-fluoren-2-yl]boronic acid(B),the synthesis process and the existing synthesis route were investigated,and the related reaction mechanism was studied.The target compound A uses 1-fluoro-2-nitrobenzene as a raw material,and is obtained by substitution,reduction,diazotization,Suzuki reaction,oxidation reaction,cyclization,and organolithium reagent reaction.The target compound B is 2-bromo-9-Fluorenone is the starting material obtained by nucleophilic addition,substitution,boronation and hydrolysis.Through the investigation of the synthetic route,the reaction route that does not react,the reaction yield is low,the economy is poor,and is not suitable for pilot scale-up is eliminated,and the alkali and acid in the optimal reaction route are determined by the method of single factor investigation.,The amount of solvents and monomers,etc.,finally based on the single factor experiment,the response surface optimization method is used to optimize the feeding ratio and reaction conditions to obtain the best feeding ratio and reaction conditions.At the same time,the reaction conditions are verified by verification experiments.The yield of the target compound is the highest.The target product was confirmed by mass spectrometry,proton nuclear magnetic resonance spectrum,carbon spectrum,infrared spectrum,and melting point to confirm that its structure was consistent with the proposed compound.At the same time,the purity of the target compound A and B was determined by high performance liquid chromatography,and the target compound was synthesized The final purity is above 98%.The absorbance and fluorescence intensity in different solvents were measured by ultraviolet spectroscopy and fluorescence emission spectroscopy,and it was found that the polarity of the solvent had a certain influence on the absorbance and fluorescence intensity of the target compound.Compared with the route reported in the literature,the related synthetic route has the characteristics of simple operation,high yield,and short reaction period.The total yield of target compound A and B are 49.2% and 68.5%,respectively,compared with 26.8% and 26.8% in the literature.53.9%,a substantial increase.