Trimethyl borate → 3-Ethoxy-4-fluorobenzeneboronic acid

To a solution of 9A (3.86 g, 17.6 mmol) in THF (60 mL) at −78° C. was added n-BuLi (1.6 M in hexanes, 14.3 mL, 22.8 mmol). The mixture was stirred at −78° C. for 40 min before trimethyl borate (3.63 mL, 33 mmol) was added. The reaction was left stirring from −78° C. to rt over 4 h. It was quenched with 1.0 N HCl (40 mL), extracted with EtOAc, washed with brine and dried over Na2SO4. After evaporation of the solvent, the crude solid product was triturated with EtOAc/hexanes (1:4). After filtration, 9B (2.2 g, 69% yield) was collected as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 1.42 (t, J=7.03 Hz, 3H) 4.11 (q, J=7.03 Hz, 2H) 7.03 (dd, J=11.42, 8.35 Hz, 1H) 7.18-7.29 (m, 2H) 7.35 (d, J=7.91 Hz, 1H).

1. additionwas added
2. waitThe reaction was left
3. customIt was quenched with 1.0 N HCl (40 mL)
4. extractionextracted with EtOAc
5. washwashed with brine
6. dry with materialdried over Na2SO4
7. customAfter evaporation of the solvent
8. customthe crude solid product was triturated with EtOAc/hexanes (1:4)

ORD record

ord-f451a95260c146d8bd02c6da25e347df

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08222453B2