Hydrochloric Acid → (4-(Benzo[d]oxazol-2-yl)phenyl)boronic acid

Temperature

-78 °C

In a 300 mL three-neck flask, 5.5 g (20 mmol) of 2-(4-bromophenyl)benzoxazole was placed, and the air in the flask was replaced with nitrogen. Then, 120 mL of THF was added in the flask, and the mixture was cooled to −78° C. under nitrogen stream. After cooling, 13 mL (22 mmol) of 1.6 M n-butyllithium was dripped into the solution, and the mixture was stirred at the same temperature for 2 hours. After a certain period, 4.4 mL (40 mmol) of trimethyl borate was added to the solution, and the temperature was raised to room temperature, and then, the solution was stirred for 16 hours. After a certain period, 100 mL of 1 M hydrochloric acid was added to the solution, and stirred for 1 hour. An aqueous layer of the obtained mixture was extracted with ethyl acetate. The resulting extracted solution and the organic layer were combined and washed with saturated saline, and then dried with magnesium sulfate. The mixture was gravity filtered, and the obtained filtrate was condensed to give a solid. The solid was recrystallized with ethyl acetate/hexane, so that 3.3 g of target white powder was obtained in a yield of 69%.

1. temperatureAfter cooling
2. waitAfter a certain period
3. temperaturethe temperature was raised to room temperature
4. stirringthe solution was stirred for 16 hours
5. waitAfter a certain period
6. stirringstirred for 1 hour
7. extractionAn aqueous layer of the obtained mixture was extracted with ethyl acetate
8. extractionThe resulting extracted solution
9. washwashed with saturated saline
10. dry with materialdried with magnesium sulfate
11. filtrationfiltered
12. customcondensed
13. customto give a solid
14. customThe solid was recrystallized with ethyl acetate/hexane, so that 3.3 g of target white powder
15. customwas obtained in a yield of 69%

ORD record

ord-1d87ff95e6924b3f9b0689cd4ac0542d

Source dataset

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08859108B2