4-Chlorophenylboronic acid → 5-Chloro-4-(4-chlorophenyl)-2-fluoropyridine

Temperature

140 °C

A suspension of 5-chloro-2-fluoro-4-iodopyridine (2.57 g, 10 mmol), 4-chlorophenylboronic acid (1.72 g, 11 mmol) and Pd(Ph3P)4 (462 mg, 0.4 mmol) in a mixture of 2.0 M aqueous sodium carbonate (6 mL) and toluene (10 mL) was heated at 140° C. in a microwave oven for 30 min. Analysis by HPLC/MS indicated that the reaction was not complete. Additional 4-chlorophenylboronic acid (0.156 g, 1 mmol) was added, followed by Pd(Ph3P)4 (116 mg, 0.1 mmol). The reaction mixture was again heated at 140° C. in a microwave oven for 30 min. After cooling to room temperature, the reaction mixture was diluted with water and extracted with EtOAc (50 mL×3). The combined EtOAc extracts were washed with saturated aqueous NaCl, dried over Na2SO4, filtered and concentrated under reduced pressure. The crude product was purified using a silica gel cartridge (120 g) eluted with a gradient of EtOAc (0-50%) in hexanes to afford 2.6 g of the product (60% pure) as an off-white solid. This was crystallized in EtOAc-hexanes to obtain the pure title compound (0.9 g) as a white solid. HPLC/MS: retention time=3.80 min, [M+H]+=242.0.

1. temperatureThe reaction mixture was again heated at 140° C. in a microwave oven for 30 min
2. temperatureAfter cooling to room temperature
3. extractionextracted with EtOAc (50 mL×3)
4. washThe combined EtOAc extracts were washed with saturated aqueous NaCl
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe crude product was purified
9. washeluted with a gradient of EtOAc (0-50%) in hexanes

ORD record

ord-ba1c0349207e470e980bd46dcb4a08a2

Source dataset

uspto-grants-2010_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07858639B2