反应详情

温度

60 °C

A mixture of 7-Methyl-1H-benzimidazole-4-carboxylic Acid (22) (4.944 g, 28.10 mmol) and concentrated H2SO4 (30 mL) is heated to about 60° C. to obtain a solution which is then cooled to about 0° C. To this solution is added KNO3 (3.12 g, 30.9 mmol) portionwise, so as to maintain the internal reaction temperature <10° C. Following complete addition, the cooling source is removed and the reaction mixture is allowed to warm to ambient temperature, whereupon the mixture is stirred for about 1 hour. The reaction mixture is then added to ice water (100 mL) and held at about 0° C. for about 4 hours. The resulting solids are filtered, washed with water, and dried to provide 7-Methyl-6-nitro-1H-benzimidazole-4-carboxylic Acid (23) as an off white solid (6.12 g, 98% Yield).

1. customto obtain a solution which
2. temperatureis then cooled to about 0° C
3. temperatureso as to maintain the internal reaction temperature <10° C
4. additionaddition
5. customthe cooling source is removed
6. temperatureto warm to ambient temperature, whereupon the mixture
7. additionThe reaction mixture is then added to ice water (100 mL)
8. waitheld at about 0° C. for about 4 hours
9. filtrationThe resulting solids are filtered
10. washwashed with water
11. customdried