Benzaldehyde → 3-Amino-2-phenylpyridine

Participants

Reaction Steps

A solution of palladium acetate (224.5 mg, 1.00 mmol) and triphenylphosphine (1.05 g, 4.00 mmol) in toluene (1000 mL) was stirred at room temperature for 15 minutes. Phenylboronic acid (114 g, 935 mmol), 2-chloro-3-aminopyridine (100 g, 778 mmol), benzaldehyde (83.4 g, 786 mmol), and toluene (500 mL) were then added followed by a solution of sodium carbonate (200 g, 1.89 mol) in water (1500 mL). The mixture was heated to reflux for 18 hours, cooled to room temperature, and the layers were separated. The organic layer was washed with water (500 mL) and 2.5M aqueous hydrochloric acid was added (630 mL). The aqueous layer was separated and washed with toluene (300 mL). The pH was adjusted to 12—13 using 50% aqueous sodium hydroxide and the mixture was extracted with methyl-tert-butyl ether (500 mL). The organic layer was concentrated and the product was crystallized from diisopropyl ether to afford 2-phenyl-3-aminopyridine (128 g, 97% yield). M. p.=67-68° C. 1H NMR (300 MHz, CDCl3) δ3.88 (bs, 2), 7.02-7.11 (m, 2). 7.28-7.53 (m, 3), 7.67-7.71 (m, 2), 8.,13-8.16 (m, 1). 13C NMR (100 MHz, CDCl3) δ122.57, 122.96, 128.14, 128.38, 128.72, 138.54, 139.86, 139.93, 144.93.

Provenance & Evidence