CON(C)[C:4]([C:6]1[C:14]2[N:13]=[CH:12][NH:11][C:10]=2[CH:9]=[CH:8][CH:7]=1)=[O:5].[Li][CH3:17].[NH4+].[Cl-].O>C1COCC1>[NH:11]1[C:10]2[CH:9]=[CH:8][CH:7]=[C:6]([C:4](=[O:5])[CH3:17])[C:14]=2[N:13]=[CH:12]1
To a stirred solution of 1H-benzoimidazole-4-carboxylic acid methoxy-methyl-amide (742 mg, 3.62 mmol) in THF (36 mL) at −78° C. was added MeLi (1.6M; 2.49 mL, 3.98 mmol) dropwise. The mixture was stirred at −78° C. for 2 hours before an additional 1.0 mol. eq. MeLi (2.3 mL) was added dropwise. The mixture was stirred at −78° C. for a further 2 hours before saturated aqueous NH4Cl solution was added and the mixture warmed to room temperature. Enough water was added to dissolve all solids and the phases were separated. The aqueous phase was extracted into CHCl3 (×3), dried and concentrated in vacuo to give a white solid. Trituration with EtOAc (5 mL) followed by collection by filtration and washing with 4:1 Et2O/EtOAc (5 mL) provided 1-(1H-benzoimidazol-4-yl)-ethanone (487 mg).
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