Hydrochloric Acid → 4-(9H-Carbazol-9-yl)phenylboronic Acid

Then, 21.8 g (67.5 mmol) of 9-(4-bromophenyl)carbazole was put into a 500 mL three-necked flask, and the air in the flask was replaced with nitrogen. Then, 200 mL of tetrahydrofuran (THF) was added thereto. The temperature in the flask was set to be −78° C. and then, 48.9 mL (74.3 mmol) of n-butyllithium (1.52 mol/L, hexane solution) was dropped to the mixture and was stirred for 2 hours at the same temperature. Then, 17.4 mL (155 mmol) of trimethyl borate was added thereto. The mixture was stirred for one hour at the same temperature, then, was stirred for 24 hours while raising the temperature to room temperature. After the reaction, 200 mL of hydrochloric acid (1.0 mol/L) was added to the reaction mixture, and then stirred for one hour at room temperature. After that, the organic layer in the reaction mixture was washed with water and the product was extracted with ethyl acetate from the water which was used for the washing. The obtained extraction solution and the organic layer, which was washed with water, were mixed. The mixture was further washed with a saturated aqueous solution of sodium chloride, and then dried with magnesium sulfate. After the drying, the mixture was suction filtrated, and the filtrate was concentrated. The obtained residue was recrystallized with a mixed solvent of chloroform and hexane to give 12.8 g of a white powdered solid of 4-(carbazol-9-yl)phenylboronic acid (yield: 65.9%). A synthesis scheme (f-3) of 4-(carbazol-9-yl)phenylboronic acid is shown below.

1. customto be −78° C.
2. stirringThe mixture was stirred for one hour at the same temperature
3. stirringwas stirred for 24 hours
4. additionwas added to the reaction mixture
5. stirringstirred for one hour at room temperature
6. washAfter that, the organic layer in the reaction mixture was washed with water
7. extractionthe product was extracted with ethyl acetate from the water which
8. extractionThe obtained extraction solution
9. washthe organic layer, which was washed with water
10. additionwere mixed
11. washThe mixture was further washed with a saturated aqueous solution of sodium chloride
12. dry with materialdried with magnesium sulfate
13. filtrationfiltrated
14. concentrationthe filtrate was concentrated
15. customThe obtained residue was recrystallized with a mixed solvent of chloroform and hexane

ORD record

ord-88ce3eacdf5c47b7957d5de6034db3f3

Source dataset

uspto-grants-2010_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07758972B2