Oxalic Acid → 2-(3-Bromophenyl)benzimidazole

Participants

Reaction Conditions

Reaction Steps

Method 1—Step a O-phenylenediamine (81.8 g, 756.6 mmol) and oxalic acid (3.40 g, 37.8 mmol) were completely dissolved in EtOH—H2O/1:1 (2 L) previously warmed at 80° C. 3-Bromobenzaldehyde (44.10 mL, 378.30 mmol) was then added dropwise to the solution. The reaction mixture was stirred overnight at 70° C. to the open air. The day after solid was filtered off and triturated with MeOH (150 mL) to give the product as a pale yellow solid (27.50 g). 3.8 g were recovered from the mother liquors. Total yield 31.30 g (30%).

Provenance & Evidence