反应详情

温度

60 °C

To a stirred solution of benzimidazole-5-carboxylic acid (Aldrich, 10 g, 61.7 mmol) in EtOH (200 mL) was added dropwise conc. H2SO4 (8 mL), and the solution was heated to reflux. After 1 h the solution was cooled to 60° C. and stirred for 16 h. The solution was then concentrated in vacuo and the residue was partitioned between EtOAc and saturated Na2CO3 solution. The layers were separated and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried (Na2SO4), and concentrated in vacuo to afford the title compound as a brown solid:

1. temperaturethe solution was heated to reflux
2. concentrationThe solution was then concentrated in vacuo
3. customthe residue was partitioned between EtOAc and saturated Na2CO3 solution
4. customThe layers were separated
5. extractionthe aqueous layer was extracted with EtOAc
6. washThe combined organic layers were washed with brine
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated in vacuo