Hydrochloric Acid → 2,3,5-Trichlorophenylboronic acid

A solution of 2,3,5-trichlorobromobenzene (8.60 g, 0.033 mole) in dry ether (33 ml) and bromoethane (4.73 ml, 7.31 g, 0.067 mole) was added dropwise to a suspension of magnesium turnings (2.80 g, 0.12 mole) in dry ether (21.50 ml) at room temperature. The mixture was refluxed for 0.50 hr and cooled to room temperature. The mixture was then added dropwise under nitrogen to a solution of trimethylborate (5.16 ml, 5.16 g, 0.05 mole) in dry ether (8.60 ml) maintaining the temperature below −60° C. This was warmed to room temperature overnight, then cooled in an ice-bath and treated with 2M hydrochloric acid (10 ml). The ether layer was separated, washed with water (2×20 ml), dried over anhydrous magnesium sulphate, filtered and the filtrate evaporated in vacuo. The residue was triturated with 40-60° C. petroleum ether, filtered and dried in vacuo. Yield 4.57 g (61%), M.p. 257-260° C.

1. temperatureThe mixture was refluxed for 0.50 hr
2. temperaturemaintaining the temperature below −60° C
3. temperatureThis was warmed to room temperature overnight
4. temperaturecooled in an ice-bath
5. customThe ether layer was separated
6. washwashed with water (2×20 ml)
7. dry with materialdried over anhydrous magnesium sulphate
8. filtrationfiltered
9. customthe filtrate evaporated in vacuo
10. customThe residue was triturated with 40-60° C. petroleum ether
11. filtrationfiltered
12. customdried in vacuo

ORD record

ord-4aeb942a571146eeae9f6871027b11f2

Source dataset

uspto-grants-2003_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06503909B1