Phosphorus oxychloride → HCID 16058688, compound

Participants

Reaction Steps

To a solution of N-(2-{[3-(2,2-dipyridin-3-ylethyl)pyridin-2-yl]amino}phenyl)-3,3,3-trifluoropropanamide (127 mg) in 6 mL of dioxane was added 500 uL of POCl3. Immediate precipitation was observed. The reaction was heated at 100 C for 24 h, giving a sluggish reaction. The reaction was cooled to 0 C and carefully quenched with saturated aqueous sodium bicarbonate. then partitioned between saturated aqueous sodium bicarbonate and CH2Cl2. The aqueous solution was extracted with CH2Cl2 (2×), and the combined organic solutions were dried (Na2SO4) and concentrated. The resulting crude mixture of starting material and desired product was dissolved in 4 mL of dioxane. This solution was added dropwise to 10 mL of POCl3 stirring at 50 C. The mixture was heated at 100 C for 8 h, then cooled to room temperature and concentrated in vacuo. CH2Cl2 was added to the residue, and the resulting solution was cooled to 0 C and neutralized slowly with saturated aqueous sodium bicarbonate, then partitioned between saturated aqueous sodium bicarbonate and CH2Cl2. The aqueous solution was extracted with CH2Cl2 (3×), and the combined organic solutions were dried (Na2SO4) and purified by flash chromatography. A second purification by reverse phase HPLC provided 127 mg of 1-[3-(2,2-dipyridin-3-ylethyl)pyridin-2-yl]-2-(2,2,2-trifluoroethyl)-1H-benzimidazole as a white solid. 1H NMR (500 MHz, CDCl3): δ 8.54 (dd, J=4.6, 1.7 Hz, 1H), 8.43 (d, J=4.4 Hz, 2H), 8.31 (d, J=1.7 Hz, 1H), 8.24 (s, 1H), 7.91 (d, J=8.1 Hz, 1H), 7.69 (dd, J=7.8, 1.5 Hz, 1H), 7.40-7.35 (m, 2H), 7.31-7.28 (m, 1H), 7.22-7.20 (m, 1H), 7.18-7.11 (m, 3H), 6.92 (d, J=8.1 Hz, 1H), 4.08 (t, J=7.8 Hz, 1H), 3.73-3.64 (m, 1H), 3.52-3.43 (m, 1H), 3.29-3.21 (m, 2H).

Provenance & Evidence