反应详情

A 1L three neck round bottom flask equiped with an addition funnel and condenser was charged with a solution of 5,6-dimethylbenzimidazole (2.00 g, 13.69 mmol) dissolved in water (400 mL). The mixture was warmed to reflux and KMnO4 (8.60 g, 54.4 mmol) dissolved in water (200 mL) was added over a 0.5 h period. The reaction stirred for 0.5 h at reflux and was filtered hot through a plug a celite, washed with water (2×100 mL), acidified to pH 1 with 3N HCl and concentrated to 50 mL volume. The solution was aged for 2 h, filtered, washed with cold water and the solid was dried overnight at 50° C. under 25 mm vacuum to provide a white solid:

1. temperatureThe mixture was warmed
2. temperatureto reflux
3. additionwas added over a 0.5 h period
4. temperatureat reflux
5. filtrationwas filtered hot through a plug a celite
6. washwashed with water (2×100 mL)
7. concentrationconcentrated to 50 mL volume
8. waitThe solution was aged for 2 h
9. filtrationfiltered
10. washwashed with cold water
11. customthe solid was dried overnight at 50° C. under 25 mm vacuum
12. customto provide a white solid