Hydrochloric Acid → 2,3-Dichlorobenzeneboronic acid

Temperature

-78 °C

A solution of 1-bromo-2,3-dichlorobenzene (20 g, 0.088 mole, Aldrich) in dry tetrahydrofuran (44.24 ml) was added dropwise to a solution of n-butyllithium (1.6M in hexane, 66.36 ml, 0.11 mole) in anhydrous tetrahydrofuran (16 ml), maintaining the temperature below −65° C. The resulting pale yellow suspension was stirred at −78° C. for 75 min. Trimethylborate (13.28 ml, 12.16 g, 0.12 mole) was added dropwise maintaining the temperature below −55° C. The resulting pale yellow solution was warmed to room temperature overnight. Excess n-butyllithium was decomposed with water (30 ml) and the reaction mixture was evaporated in vacuo. The residue obtained was suspended in water and acidified with 2M hydrochloric acid (10 ml). The insoluble solid was filtered, washed well with water and dried. The solid was suspended in 60-80° C. petroleum ether, stirred at room temperature for 10 min, filtered dried in vacuo. Yield 8.42 g (50%), M.p. 235-238° C.

1. temperaturemaintaining the temperature below −65° C
2. temperaturemaintaining the temperature below −55° C
3. temperatureThe resulting pale yellow solution was warmed to room temperature overnight
4. customthe reaction mixture was evaporated in vacuo
5. customThe residue obtained
6. filtrationThe insoluble solid was filtered
7. washwashed well with water
8. customdried
9. customwas suspended in 60-80° C.
10. stirringstirred at room temperature for 10 min
11. filtrationfiltered
12. customdried in vacuo

ORD record

ord-a83069e62e534694948f88b656ae879b

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06255307B1