Hydrochloric Acid → (3,4-Dihydroxyphenyl)boronic acid

4-Bromocatechol (T-1) (18.8 g; made by Tokyo Chemical Industry Co., Ltd.) was dissolved in dry THF (200 ml), which was cooled to −70° C. n-BuLi (72 ml) was added under an atmosphere of nitrogen and the stirring was continued at −70° C. for 2 hours. Trimethyl borate (15.6 g) in a THF solution was then slowly added dropwise at −70° C., and the mixture was warmed to room temperature and stirred for 16 hours. After the completion of the reaction, 2N HCl (100 ml) was added and the mixture was extracted with toluene. The extract was washed with water and brine, and dried over anhydrous magnesium sulfate. The extract was concentrated under reduced pressure to give pale brown solids. The solids were recrystallized (heptane:toluene=4:1 by volume) to give 3,4-dihydroxyphenylboronic acid (T-2; 9.7 g; yield 63%) as colorless crystals.

1. additionwas added under an atmosphere of nitrogen
2. additionwas added
3. extractionthe mixture was extracted with toluene
4. washThe extract was washed with water and brine
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationThe extract was concentrated under reduced pressure
7. customto give pale brown solids
8. customThe solids were recrystallized (heptane:toluene=4:1 by volume)

ORD record

ord-fff9240641b34d10a22bee33806707b5

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09157027B2