3,4-Diaminobenzoic acid → 2-(4-methoxycarbonylmethoxy-2,6-dimethylphenyl)-3H-benzoimidazole-5-carboxylic acid

Participants

Reaction Steps

To a solution (4-formyl-3,5-dimethylphenoxy)-acetic acid methyl ester (2.4 g) (from Example 6-9) and 3,4-diaminobenzoic acid (2.0 g) in DMSO (30 mL) under air at ambient temperature was added FeCl3 (150 mg) and the resulting brown reaction mixture was stirred at the same temperature overnight. The reaction was monitored by LC/MS which indicated completion. The reaction mixture was then decanted into 400 mL of stirred water and the resulting precipitate was collected by filtration and washed with water. The crude product was dried in the suction funnel for 4 h to give 2-(4-methoxycarbonylmethoxy-2,6-dimethylphenyl)-3H-benzoimidazole-5-carboxylic acid. MS (ESI) m/z 355.04 (M+H); Retention time=0.79 min (Method 10).

Provenance & Evidence