Sodium Carbonate → 4-(3-Phenylimidazo[1,2-a]pyridin-7-yl)benzaldehyde

Participants

Reaction Steps

Tetrakis(triphenylphosphoine)palladium(0) (92 mg, 0.080 mmol, 0.050 equiv) was added to a deoxygenated mixture of 4-(3-iodoimidazo[1,2-a]pyridin-7-yl)benzaldehyde (2-4, 555 mg, 1.94 mmol, 1 equiv), phenyl boronic acid (486 mg, 3.99 mmol, 2.50 equiv), and aqueous saturated sodium carbonate solution (2.4 mL, 3.0 equiv) in dioxane (20 mL), and the resulting mixture was heated at reflux for 4 h. Additional tetrakis(triphenylphosphoine)palladium(0) (100 mg, 0.09 mmol, 0.05 equiv), phenyl boronic acid (500 mg, 4.0 mmol, 2.5 equiv), aqueous saturated sodium carbonate solution (2.5 mL, 3.1 equiv), and lithium chloride (200 mg, 5 mmol, 3 equiv) were added and the mixture was heated at reflux for 18 h. The reaction mixture was cooled, then concentrated, and the residue was partitioned between half-saturated aqueous NaCl solution (100 mL) and EtOAc (6×100 mL). The combined organic layers were dried over sodium sulfate and concentrated. The residue was purified by reverse-phase liquid chromotography (H2O/CH3CN gradient w/0.1% TFA) to give 4-(3-phenylimidazo[1,2-a]pyridin-7-yl)benzaldehyde (2-5) as a tan solid. LRMS m/z (M+H) Calcd 299.3, found 298.9.

Provenance & Evidence