97511-05-2

121-43-7

108847-20-7

The general procedure for the synthesis of dibenzothiophene-4-boronic acid from 4-bromodibenzothiophene and trimethyl borate was as follows: first, 4-bromodibenzothiophene was dissolved in anhydrous tetrahydrofuran (THF), and the reaction system was cooled to -78 °C. Under nitrogen protection, n-butyllithium (2.5 M hexane solution) was slowly added dropwise, maintaining the reaction temperature at -78 °C. After the dropwise addition, the reaction system was warmed to 0 °C and stirring was continued for 1 hour. Subsequently, the reaction system was again cooled to -78 °C and trimethyl borate was slowly added dropwise. After completion of dropwise addition, the reaction system was gradually warmed to room temperature and stirred for 12 hours. After completion of the reaction, the reaction mixture was slowly poured into 2N aqueous hydrochloric acid solution and stirred for 30 minutes. The aqueous phase was extracted with ether and the organic phase was combined. The organic phase was dried with anhydrous magnesium sulfate and filtered to remove the desiccant. The filtrate was concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography to afford the target product dibenzothiophene-4-boronic acid in 82% yield.