Br[C:2]1[C:10]2[N:9]=[C:8]([CH3:11])[NH:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.C([Li])CCC.C([O:19][C:20](=O)[C:21]([F:24])([F:23])[F:22])C>C1COCC1>[F:22][C:21]([F:24])([F:23])[C:20]([C:2]1[C:10]2[N:9]=[C:8]([CH3:11])[NH:7][C:6]=2[CH:5]=[CH:4][CH:3]=1)=[O:19]4-Bromo-2-methyl-1H-benzimidazole (500 mg, 2.37 mmol) was dissolved in THF (8 mL) and cooled to −78° C. n-Butyllithium (2.3 mL, 2.5 M in hexanes, 5.7 mmol) was added dropwise and the reaction was stirred at −78° C. for 30 min. Trifluoroacetic acid ethyl ester (339 μL, 2.8 mmol) was added and the reaction was stirred at 0° C. for 1 h. The reaction was quenched with HCl (2 N, 4 mL), then extracted with water and EtOAc, washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. Purification by normal phase silica gel column chromatography (CH2Cl2/MeOH/NH4OH) provided 2,2,2-trifluoro-1-(2-methyl-1H-benzoimidazol-4-yl)-ethanone.
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