反应详情

4-(Acetylamino)-2-methylbenzoic acid (3.93 g, 20.3 mmol) was taken up in concentrated sulfuric acid (20 mL) and warmed to solubilize. The solution was then cooled with an ice bath. Fuming nitric acid (0.86 mL) in sulfuric acid (2.0 mL) was added dropwise and the resultant solution was stirred one hour. The solution was then diluted with water and a yellow solid was collected by filtration and discarded. Upon standing, an orange solid formed in the filtrate, which was collected by filtration to give (0.61 g) of 4-amino-2-methyl-3-nitrobenzoic acid. The aqueous filtrate was then extracted (3×100 mL of 10% methanol in ethyl acetate), and the combined organic layers were dried (magnesium sulfate), filtered and concentrated to yield additional 4-amino-2-methyl-3-nitrobenzoic acid (0.90 g). 1H NMR (400 MHz, d6-DMSO): 7.75 (d, 1H), 6.75 (d, 1H), 2.41 (s, 3H). MS (EI) for C8H8N2O4: 195 (MH+).

1. temperaturewarmed to solubilize
2. temperatureThe solution was then cooled with an ice bath
3. filtrationa yellow solid was collected by filtration
4. customan orange solid formed in the filtrate, which
5. filtrationwas collected by filtration