[F:1][C:2]1[CH:3]=[C:4]([NH2:10])[C:5]([NH2:9])=[CH:6][C:7]=1[F:8].O.[N:12]#[C:13]Br.C(=O)([O-])O.[Na+]>C(#N)C>[F:1][C:2]1[C:7]([F:8])=[CH:6][C:5]2[NH:9][C:13]([NH2:12])=[N:10][C:4]=2[CH:3]=14,5-Difluorobenzene-1,2-diamine (0.651 g, 0.562 mmol, commercially available from Matrix Scientific) in acetonitrile (10 mL) and water (2 ml) at 0° C. was treated with cyanogen bromide (0.063 g, 0.6 mmol). The reaction mixture was allowed to warm to room temperature, and then stirred for 14 hours. The reaction mixture was then treated with saturated aqueous sodium hydrogen carbonate solution (50 ml) and shaken. The resulting solid was filtered off, washed with water and dried under reduced pressure to give 0.39 g of 5,6-difluoro-1H-benzo[d]imidazol-2-amine (yield, 40%). MS (EI): 186 (MH+).
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