反应详情

Bromo-acetic acid (1.23 g, 8.84 mmol, 2.0 eq) is added at room temperature to a stirred solution of 4-nitro-1H-pyrazole (500 mg, 4.42 mmol, 1.0 eq) in tetrahydrofuran (50 mL), followed by potassium carbonate (6.15 g, 44.2 mmol, 10.0 eq). The reaction mixture is heated under reflux for 2 hours, solvent is then evaporated, the residue is extracted with ethyl acetate (3×40 mL) and water (40 mL), and the pH is adjusted to 4 by the addition of a 0.1N hydrochloric acid aqueous solution. The combined organic layers are dried over sodium sulfate, filtered and concentrated to afford (4-nitro-pyrazol-1-yl)-acetic acid as a light yellow solid (589 mg, 78% yield).

1. temperatureThe reaction mixture is heated
2. temperatureunder reflux for 2 hours
3. customsolvent is then evaporated
4. extractionthe residue is extracted with ethyl acetate (3×40 mL) and water (40 mL)
5. additionthe pH is adjusted to 4 by the addition of a 0.1N hydrochloric acid aqueous solution
6. dry with materialThe combined organic layers are dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated