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, 48 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 phases were combined, dried over sodium sulfate, filtered and 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 materialdried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo