Trimethyl borate → (4-(2-(Pyrrolidin-1-yl)ethoxy)phenyl)boronic acid

Temperature

-78 °C

To a solution of 1-[2-(4-bromophenoxy)ethyl]-pyrrolidine (2.70 g, 10 mmol) in THF (40 mL) was added n-butyl lithium (6.9 mL 1.6 M in hexanes, 11 mmol) at −78° C. The reaction mixture was stirred at −78° C. for 15 min and then at 0° C. for 15 min. Trimethyl borate (2.5 mL, 22 mmol) was then added to the reaction mixture at 0° C. The mixture was gradually warmed to room temperature overnight. Methyl borate in the reaction mixture was hydrolyzed by reacting with saturated NH4Cl aqueous solution (100 mL) at room temperature for 30 min. The upper organic layer was collected. The aqueous layer was extracted with CHCl3 (2×100 mL). The organic layers were combined, washed with brine (2×100 mL) and dried with MgSO4. The solvent was evaporated, resulting in a dense oil which was purified by column chromatograph (10% MeOH/CHCl3 and 1% Et3N) to yield the product as a white solid.

1. waitat 0° C. for 15 min
2. temperatureThe mixture was gradually warmed to room temperature overnight
3. customThe upper organic layer was collected
4. extractionThe aqueous layer was extracted with CHCl3 (2×100 mL)
5. washwashed with brine (2×100 mL)
6. dry with materialdried with MgSO4
7. customThe solvent was evaporated
8. customresulting in a dense oil which
9. customwas purified by column chromatograph (10% MeOH/CHCl3 and 1% Et3N)

ORD record

ord-10dd354e17ed47849f978ad18b48a48a

Source dataset

uspto-grants-2003_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06635638B2