Reacción #1009444

Ecuación de reacción

tri-isopropyl borate

4-bromo-3,5-dimethyl-1,2-oxazole

n-butyl lithium

→

(3,5-Dimethyl-1,2-oxazol-4-yl) boronic acid

Rendimiento 12.5%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrowas brought to −78° C.
2. 2
   Otroto reached room temperature
3. 3
   workup.STIRRINGstirred about 16 h
4. 4
   OtroThen removed the solvent under reduced pressure
5. 5
   Otroquenched with saturated NH4Cl solution
6. 6
   Extracciónextracted with ethyl acetate
7. 7
   LavadoThe organic layer was washed with water
8. 8
   Secadodried over anhydrous Na2SO4
9. 9
   Otroremoved the solvent under reduced pressure
10. 10
    OtroThe obtained crude material
11. 11
    Otrowas purified by silica gel column chromatography
12. 12
    Otroto obtain white solid

Procedimiento

To a 500 mL three RB flask fitted with magnetic stirrer was charged 4-bromo-3,5-dimethyl-1,2-oxazole (4.0 g, 22.7 mmol) in THF (40 mL), cooled −78° C. To the stirred solvent was added n-butyl lithium (28.4 mL, 1.6M solution, 45.0 mmol) drop wise and stirred at −65° C. about 30 minutes. The RM was brought to −78° C., was added tri-isopropyl borate (12.81 g, 68.0 mmol), once the temperature to reached room temperature and stirred about 16 h. Then removed the solvent under reduced pressure and quenched with saturated NH4Cl solution and extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous Na2SO4 and removed the solvent under reduced pressure. The obtained crude material was purified by silica gel column chromatography to obtain white solid. (0.4 g, yield: 12.5%).

Fuente