[CH3:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([N:8]2[CH:12]=[C:11]([CH3:13])[CH:10]=[N:9]2)[N:3]=1.C([Li])CCC.[Br:19]N1C(=O)CCC1=O.[Cl-].[NH4+]>C1COCC1.C(OCC)(=O)C>[Br:19][C:12]1[N:8]([C:4]2[CH:5]=[CH:6][CH:7]=[C:2]([CH3:1])[N:3]=2)[N:9]=[CH:10][C:11]=1[CH3:13]
To a cold (−60° C.) solution of 2-methyl-6-(4-methyl-pyrazol-1-yl)-pyridine (0.52 g) (prepared by Reaction Condition 1 in Step i) in 14 mL of anhydrous THF was added 1.33 mL of a 2.5M solution of n-butyllithium (0.21 g) in hexanes. The reaction mixture was stirred at −60° C. for one hour. A 10 mL solution of N-bromosuccinimide (0.59 g) in THF was added and then the final solution was stirred at −60° C. for 2 hours. Saturated ammonium chloride (20 mL) was added and then the reaction mixture was allowed to warm to 24° C. The reaction mixture was diluted with 300 mL of ethyl acetate and then the aqueous phase was separated. The organic phase was washed with additional saturated ammonium chloride (50 mL) and then with brine (50 mL). The organic layer was separated, dried (sodium sulfate), filtered, and then the filtrate was evaporated to give a crude red oil. Purification by flash chromatography (silica gel, 20% ethyl acetate in heptane) provided, after drying, 0.377 g of the title compound as a yellow oil; 1H-NMR (400 MHz; DMSO-d6) δ 7.88 (t, 1H), 7.69 (s, 1H), 7.44 (s, 1H), 7.32 (s, 1H), 2.50 (s, 3H), 2.02 (s, 3H); MS (APCI+) m/z 254 (MH+).
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