Tributyl borate → 2-Fluoropyridine-4-boronic acid

Temperature

-78 °C

To a stirred solution of n-butyl lithium (3.2 mL, 2.5M, 8.0 mmol) in dry diethyl ether (20 mL) at −78° C. was added a solution of 2-fluoro-4-iodopyridine (1.5 g, 6.7 mmol) in dry ether (10 mL) and the reaction mixture was stirred at −78° C. for 10 minutes. Tributyl borate (2.4 mL, 2.01 g, 8.7 mmol) was added and the reaction mixture was allowed to warm to room temperature over 2 hours. Water (5 mL) was added followed by 2N aqueous sodium hydroxide solution (10 mL) to dissolve the solids. The organic phase was separated. The aqueous phase was acidified to pH3 using 6N hydrochloric acid and the resulting white solid was collected by filtration and dried under vacuum to give the title compound, 0.74 g (78%). 1H NMR (DMSO-d6) δ 8.65 (br s, 2H), 8.21 (d, 1H), 7.59 (t, 1H), 7.37 (d, 1H).

1. temperatureto warm to room temperature over 2 hours
2. dissolutionto dissolve the solids
3. customThe organic phase was separated
4. filtrationthe resulting white solid was collected by filtration
5. customdried under vacuum

ORD record

ord-818a01334c304c44a5c8ea295feda5c3

Source dataset

uspto-grants-2007_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07163940B2