[CH3:1][C:2]1[C:11]([N+:12]([O-])=O)=[C:10]([NH:15][CH3:16])[CH:9]=[CH:8][C:3]=1[C:4]([O:6][CH3:7])=[O:5].[C:17](O)(=O)C>[Pd].C(OCC)(=O)C>[CH3:17][N:15]1[C:10]2[CH:9]=[CH:8][C:3]([C:4]([O:6][CH3:7])=[O:5])=[C:2]([CH3:1])[C:11]=2[N:12]=[CH:16]1A mixture of methyl 2-methyl-4-(methylamino)-3-nitrobenzoate (90 mg, 0.4 mmol), 10% palladium on charcoal (Degussa type, 90 mg), acetic acid (124 uL, 1.5 mmol), and ethyl acetate (20 mL) was shaken in a Parr hydrogenation apparatus at 40 psi for 18 hours. The reaction mixture was then filtered and concentrated. The residue was dissolved in formic acid was stirred at 100° C. for 1.5 hour. The reaction mixture was concentrated, quenched with ice-water (15 mL) and the pH was adjusted to basic by portion-wise sodium bicarbonate addition then extracted with ethyl acetate. The combined extract was washed with water (2×30 mL), brine (30 mL), dried over sodium sulfate, filtered and concentrated to give methyl 1,4-dimethyl-1H-benzimidazole-5-carboxylate (78 mg, 95% yield). MS (EI) for C 1H12N2O2: 205 (MH+).
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