反应详情

温度

0 °C

Methyl 3,4-diamino-2-methylbenzoate (0.27 g, 1.5 mmol) was taken up in concentrated sulfuric acid (30 mL) and heated to solubilize, then cooled with an ice bath. Concurrently, sodium nitrite (0.14 g, 2.1 mmol) was solubilized in concentrated sulfuric acid (8.4 mL) using heating. This sodium nitrite solution was then cooled and added dropwise to the cooled solution of diamine. The mixture was stirred at 0° C. for 30 minutes then warmed to 60° C. for 15 minutes. The solution was then poured onto ice and extracted with 10% methanol in ethyl acetate (2×100 mL). The combined organic layers were dried (magnesium sulfate), filtered and concentrated to give 0.3 g of crude methyl 7-methyl-1H-benzotriazole-6-carboxylate, which was taken up in methanol (5 mL) and tetrahydrofuran (10 mL) and treated with 2M aqueous lithium hydroxide (5 mL), then heated to 70° C. for one hour. This solution was made acidic using concentrated aqueous hydrochloric acid, then extracted with 10% methanol in ethyl acetate (2×50 mL). The combined organic layers were dried (magnesium sulfate), filtered and concentrated to give 0.26 g of 7-methyl-1H-benzotriazole-6-carboxylic acid. 1H NMR (400 MHz, d6-DMSO): 7.94 (d, 1H), 7.72 (m, 1H), 2.95 (s, 3H). MS (EI) for C8H7N3O2: 178 (MH+).

1. temperatureheated
2. temperaturecooled with an ice bath
3. temperatureusing heating
4. temperaturethen warmed to 60° C. for 15 minutes
5. additionThe solution was then poured onto ice
6. extractionextracted with 10% methanol in ethyl acetate (2×100 mL)
7. dry with materialThe combined organic layers were dried (magnesium sulfate)
8. filtrationfiltered
9. concentrationconcentrated