反应详情

温度

0 °C

Six conical flasks were charged with pyrazol-1-yl-acetic acid ethyl ester (6×9.66 g, 6×62.6 mmol) and concentrated sulphuric acid (6×20 ml) was added. The solutions were cooled to 0° C. and concentrated nitric acid (6×10 ml) was added dropwise. The reaction mixtures were allowed to warm to room temperature and left standing for 18 hours. The combined organic mixtures were poured into ice (50 ml) and extracted with ethyl acetate (5×500 ml). The combined organic extracts were washed with brine (500 ml), dried (MgSO4), filtered and concentrated under reduced pressure to leave a yellow solid. Recrystallisation from ethyl acetate afforded the title compound as an off-white solid (20.97 g, 33% yield).

1. additionwas added
2. customThe reaction mixtures
3. temperatureto warm to room temperature
4. waitleft
5. extractionextracted with ethyl acetate (5×500 ml)
6. washThe combined organic extracts were washed with brine (500 ml)
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customto leave a yellow solid
11. customRecrystallisation from ethyl acetate