反应详情

2,4-Difluorobenzoic acid (5 g, 0.031M) was dissolved in concentrated sulfuric acid (30 ml), and cooled to 0°. The mixture was stirred, and fuming nitric acid (d 1.567 g/ml, 1.91 ml, 0.047M) added dropwise, keeping the temperature below 5°. After stirring for 3 hours, the mix was poured onto ice, and organics extracted into dichloromethane (2×75 ml). The combined organic layers were washed with water, dried (MgSO4), and evaporated to give 2,4-difluoro-5-nitrobenzoic acid (3.9 g, 61%). Nmr (DHSO-d6): δ 7.18 (t, 1H); 8.88 (t, 1H); 9.93 (br, 1H).

1. temperaturecooled to 0°
2. customthe temperature below 5°
3. stirringAfter stirring for 3 hours
4. additionthe mix was poured onto ice
5. extractionorganics extracted into dichloromethane (2×75 ml)
6. washThe combined organic layers were washed with water
7. dry with materialdried (MgSO4)
8. customevaporated