Step a: 2,6-Dibromobenzaldehyde, toluene, 1,3-propanediol, and concentrated sulfuric acid are heated to reflux and water is removed. After the reaction is complete, the mixture is cooled to room temperature, neutralized with sodium methoxide, and distilled under reduced pressure to obtain intermediate a;
Step b: Intermediate a and tetrahydrofuran are cooled to -10℃ to 5℃, isopropyl Grignard reagent is added, Grignard exchange is completed, then trialkyl borate is added and the reaction is maintained at this temperature; hydrochloric acid is used to quench the reaction, organic solvent is used for extraction and separation, and the mixture is evaporated to dryness to obtain intermediate b;
Step c: Intermediate b is added to an alcohol/water mixed solvent and a copper catalyst, and hydrogen peroxide is added for reaction; sodium thiosulfate solution is used to quench the reaction, extraction and separation are performed, organic solvent is added for slurrying, and filtration is used to obtain 2-bromo-6-hydroxybenzaldehyde.
