反应详情

温度

70 °C

To a solution of ethyl 5-ethyl-1-(4-methylbenzyl)-1H-pyrazole-3-carboxylate (Step 2, 1.85 g, 6.79 mmol) in ethanol (43 mL) was added NaOH (1N aq., 13.6 mL, 13.6 mmol), and the mixture was heated at 70° C. for 3 h. The organic solvent was evaporated under vacuum and the residue was acidified with HCl (3N aq.) at 0° C. until a white solid completely precipitated from solution. The solid was filtered, washed with water, and was dried in a vacuum oven to afford the title compound as a white solid (1.53 g, 92%): 1H NMR (500 MHz, CDCl3) 7.07 (d, 2H), 6.94 (d, 2H), 6.63 (s, 1H), 5.23 (s, 2H), 2.47 (quart, 2H), 2.30 (s, 3H), 1.17 (t, 3H); ES-MS m/z 245 (MH)+, 262 (M+NH4)+; HPLC RT (Method I) 4.12 min.

1. customThe organic solvent was evaporated under vacuum
2. customwas acidified with HCl (3N aq.) at 0° C. until a white solid
3. customcompletely precipitated from solution
4. filtrationThe solid was filtered
5. washwashed with water
6. customwas dried in a vacuum oven