反应详情

3.4 g (20.5 mmol) of methyl 3,4-diaminobenzoate was dissolved in a mixture of 50 mL of ethanol and 10 mL of H2O. To this stirring solution 2.6 g (24.5 mmol) of BrCN was added in one portion, and the resulting mixture was heated under reflux for 1.0 h. The reaction mixture was cooled to room temperature, concentrated to 10 mL, then washed with ethyl acetate (20 mL). The EtOAc layer was extracted with water (20 mL). The combined water extracts were neutralized with saturated NaHCO3 solution to ˜pH 8, and the resulting suspension was extracted with EtOAc (50 mL). The organic layer was washed with water and brine solution, dried with Na2SO4, and evaporated to give 2-amino-1H-benzoimidazole-5-carboxylic acid methyl ester, which was used directly in the next step without further purification.

1. temperaturethe resulting mixture was heated
2. temperatureunder reflux for 1.0 h
3. concentrationconcentrated to 10 mL
4. washwashed with ethyl acetate (20 mL)
5. extractionThe EtOAc layer was extracted with water (20 mL)
6. extractionthe resulting suspension was extracted with EtOAc (50 mL)
7. washThe organic layer was washed with water and brine solution
8. dry with materialdried with Na2SO4
9. customevaporated