反应详情

To a solution of 3-methyl-1H-pyrazole-4-carboxylic acid (1.26 g, 10 mmol) in methanol (100 mL) was added thionyl chloride (5.73 g, 45 mmol) at 0° C. The mixture was stirred for 12 hours. The solvent was evaporated in vacuo. To the residue, saturated sodium bicarbonate aqueous solution was added and the mixture was extracted with ethyl acetate (100 mL×3), the organic phase was dried by sodium sulfate. The mixture was filtered and the filtrate was concentrated in vacuo to give methyl 3-methyl-1H-pyrazole-4-carboxylate (0.8 g, 57%). 1H NMR (300 MHz, CDCl3): δ 7.87 (s, 1H), 3.84 (s, 3H), 2.53 (s, 3H).

1. customThe solvent was evaporated in vacuo
2. additionTo the residue, saturated sodium bicarbonate aqueous solution was added
3. extractionthe mixture was extracted with ethyl acetate (100 mL×3)
4. dry with materialthe organic phase was dried by sodium sulfate
5. filtrationThe mixture was filtered
6. concentrationthe filtrate was concentrated in vacuo