Toluene → 5-Nitro-2-phenylpyridine

참여 물질

반응 단계

A mixture of toluene (15 mL) and water (5 mL) was degassed with argon for 5 minutes. Sodium carbonate (0.802 g, 0.00454 mole) was then added and the mixture was degassed with argon for 5 minutes. Phenylboronic acid (0.587 g, 0.00454 mole) and 2-chloro-5-nitro-pyridine (0.6 g, 0.0037 8 mole) were then added and the resulting mixture was degassed with argon for 5 minutes. Tetrakis(triphenylphosphine)palladium(0) (0.878 g, 0.00076 mole) was added and the mixture was degassed with argon for 5 minutes. The resulting mixture was then heated to reflux for 3 hours. The mixture was diluted with ethyl acetate, and the organic layer was washed with water followed by brine solution. The ethyl acetate layer was dried over sodium sulfate and concentrated under reduced pressure. Purification by column chromatography using silica gel 60-120 mesh (5% ethyl acetate in hexane) afforded 0.5 g (66%) of 5-nitro-2-phenyl-pyridine. LCMS purity: 201 (M+1)+, 98.2%, 1H NMR (DMSO-d6): δ 9.5 (s, 1H), 8.55 (dd, 1H), 8.1 (m, 2H), 7.9 (d, 1H), 7.55 (m, 3H). To a stirred solution of 5-nitro-2-phenyl-pyridine (0.5 g, 0.0025 mole) in THF (10 mL) was added ammonium chloride (1.1 g, 0.020 mole) dissolved in water (15 mL). Methanol (5 mL) was then added, resulting in a clear solution. Zinc powder (1.3 g, 0.020 mole) was then added portionwise and the resulting mixture was stirred for 1 hour. The mixture was filtered through a bed of celite and the filtrate was concentrated under reduced pressure. The residue was extracted with ethyl acetate, and the organic layer was washed with brine solution, dried over Na2SO4, and evaporated under reduced pressure to afford 0.35 g (82%) of 6-phenyl-pyridin-3-ylamine. LCMS purity: 171.08 (M+1)+, 87.9%, 1H NMR (DMSO-d6): δ 8.12 (d, 1H), 8.0 (d, 2H), 7.72 (d, 1H), 7.48 (t, 2H), 7.36 (t, 1H), 7.1 (dd, 1H), 5.6 (s, 2).

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