反应详情

2-(4-Chloro-2-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole-4-carboxylic acid (54; 500 mg, 1.46 mmol) was suspended in CH2Cl2 (15 mL). Methanol (2 mL) was added to solubilize. To the reaction solution was added dropwise oxalyl chloride (130 μL, 1.46 mmol). After having stirred the reaction at room temperature overnight, the reaction was concentrated. The residue was taken up in EtOAc and washed successively with saturated NaHCO3 and then brine. The organic layer was dried over MgSO4, filtered, and concentrated. Purification by silica gel chromatography (EtOAc/pentane) afforded methyl 2-(4-chloro-2-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole-4-carboxylate as an orange solid (structure not shown) (390 mg, yield: 75%).

1. customthe reaction at room temperature overnight
2. concentrationthe reaction was concentrated
3. washwashed successively with saturated NaHCO3
4. dry with materialThe organic layer was dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by silica gel chromatography (EtOAc/pentane)