Triphenylphosphine → 5-Bromo-3,3'-bipyridine

Participants

Reaction Conditions

Reaction Steps

Compound 6 (see WO2009/009756) was prepared as follows: a mixture of 3,5-dibromopyridine (10.6 g, 44.7 mmol), pyridin-3-ylboronic acid (5.50 g, 44.7 mmol), palladium(II) acetate (0.550 g, 2.45 mmol), triphenylphosphine (2.50 g, 9.53 mmol), potassium phosphate tribasic (19.0 g, 89.5 mmol), H2O (45 mL) and 1,4-dioxane (200 mL) was degassed with argon for 2 h. while stirring. The reaction mixture was then maintained under argon at reflux (120° C.) while stirring for 1.5 h. Upon confirming consumption of the starting material by TLC (SiO2, 7:3 dichloromethane-acetone), the reaction was cooled to RT and poured over ethyl acetate (about 400 mL). The organic phase was then washed with saturated NaHCO3, H2O and brine, dried over MgSO4, filter and concentrated in vacuo. The crude product was purified via flash chromatography (SiO2, 4:1 dichloromethane-acetone) to provide Compound 6 (5.03 g, 48%) as a white solid.

Provenance & Evidence