Toluene → 4-Methyl-2,5-diphenylpyridine

Participants

Reaction Steps

Phenylboronic acid (72.9 g, 598 mmol), 2,5-dibromo-4-methylpyridine (50 g, 199 mmol), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (3.3 g, 8 mmol), potassium phosphate tribasic monohydrate (137 g, 595 mmol), 650 mL of toluene and 150 mL of water were placed in a 2 L round-bottom flask. Nitrogen was bubbled directly into the reaction mixture for 30 min after which tris(dibenzylideneacetone)dipalladium(0) (1.79 g, 1.96 mmol) was added. Nitrogen was bubbled into the reaction mixture for another 15 min before the reaction mixture was heated to reflux for 16 h under nitrogen. After the reaction was completed the mixture was cooled and the organic layer was separated from the aqueous layer. The organic layer was washed with a saturated brine solution and then dried over magnesium sulfate. The solution was filtered, and the solvent was removed under vacuum to give a yellow solid as the crude. The crude was purified by column chromatography using silica gel as the stationary phase and 10% ethyl acetate in hexanes as the mobile phase. The product was further purified by recrystallization from hexanes. 42.6 g of desired product was obtained after purification (87.2% yield).

Provenance & Evidence