反应详情

温度

60 °C

To fuming nitric acid (1.26 mL, 29.97 mmol, 2.0 eq.) at 0° C. was slowly added fuming sulfuric acid (9.76 mL, 104.90 mmol, 7.0 eq.) dropwise over 30 minutes. 1,3-Dimethyl-1H-pyrazole-5-carboxylic acid (2.10 g, 14.98 mmol) was then added portion wise, maintaining the internal temperature below 60° C. The reaction mixture was stirred at 60° C. under N2 for 4 h and then cooled to room temperature (RT). The reaction mixture was poured onto ice. Once ice melted the reaction mixture was extracted with EtOAc (3×500 mL). The organic layers were combined and washed with water and brine, dried (Na2SO4), filtered and evaporated in vacuo to give the desired compound as a white solid (2.67 g, 96.1%). 1H NMR (DMSO-d6, 500 MHz) δ ppm 3.87 (s, 3H), 2.39 (s, 3H); TLC (15% MeOH/DCM): Rf=0.12.

1. customat 0° C.
2. customdropwise over 30 minutes
3. temperaturemaintaining the internal temperature below 60° C
4. temperaturecooled to room temperature (RT)
5. additionThe reaction mixture was poured onto ice
6. extractionwas extracted with EtOAc (3×500 mL)
7. washwashed with water and brine
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. customevaporated in vacuo