Preparation of 1-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-2-(6-methylpyridin-2-yl)ethane-1,2-dione (a compound of the formula ( V) wherein Ra = CH3) 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. % 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. Light yellow solid, yield 6.02 g, 92%
