| 92% |
at 60 – 70℃; for 2.00 h; |
To a stirred suspension of 2-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-1-(6-methylpyridin-2-yl)ethanone (6.20 g, 24.57 mmol) in DMSO (48 mL) was added dropwise HBr (48 wt. percent in water, 5.96 g, 12.4 mL) at 0° C., and the mixture was heated at 60-70° C. After 2 h, the reaction mixture was cooled to 0° C., poured onto ice water (20 mL), and basified to pH 10 with solid K2CO3. The mixture was extracted with CHCl3 (2.x.250 mL), and the organic phase was washed with water (2.x.100 mL), dried over anhydrous Na2SO4, filtered, and evaporated to dryness under reduced pressure. The residue was purified by MPLC on silica gel using a mixture of MeOH and CH2Cl2 as eluent to give the titled compound (6.02 g, 92percent) as a light yellow solid. 1H NMR (400 MHz, CDCl3): δ 9.11 (dd, 1H, J=1.6, 1.2 Hz), 8.47 (s, 1H), 8.14 (dd, 1H, J=9.2, 1.6 Hz), 8.04 (br d, 1H, J=7.6 Hz), 7.88 (dd, 1H, J=9.2, 1.2 Hz), 7.84 (t, 1H, J=7.8 Hz), 7.42 (br d, 1H, J=8.0 Hz), 2.49 (s, 3H). |