2-Hydroxyphenylboronic acid

1034050-50-4

89466-08-0

General procedure for the synthesis of 2-hydroxyphenylboronic acid from 2-methoxyphenylboronic acid: 1.5 kg of 2-methoxyphenylboronic acid was added to a 30 L glass reactor under nitrogen protection, followed by 18 L of anisole and 1.56 kg of acetyl chloride. After the addition was completed, the reaction mixture was cooled to -10 to 0 °C and stirred at this temperature for 1 hour. Then, 133 g of anhydrous aluminum trichloride was added in batches. After the addition was completed, the reaction mixture was allowed to warm up naturally to room temperature and stirred continuously until the TLC detection showed that the reaction of the raw material was complete, a process that usually takes 8 to 10 hours. During the reaction, the solids in the reaction mixture were first gradually dissolved, followed by gradual precipitation of solids. Upon completion of the reaction, the reaction was quenched with 5 M aqueous potassium hydroxide and the pH was adjusted to 11 to 12. The organic layer was separated and discarded. The pH was adjusted to 2~3 by adding 6 M aqueous hydrochloric acid to the aqueous layer and then extracted twice with 12 L ethyl acetate, the organic layers were combined and washed with saturated brine. The organic layer was rotary evaporated to dryness and finally pulped with acetone/n-heptane to give 1.06 kg of 2-hydroxyphenylboronic acid in 77% yield and 98.6% HPLC purity.