反应详情

To a solution of 5-nitro-1H-pyrazole-3-carboxylic acid (2.0 g, 12.7 mmol) in anhydrous methanol (20 ml) at to 0° C. was added thionyl chloride (3.94 g, 2.42 ml, 33.1 mmol) drop wise. The resulting solution was heated to reflux for 2 h. The cooled solution was evaporated to dryness and the residue was treated with methanol (20 ml). The resulting solution was evaporated to dryness to give 5-nitro-2H-pyrazole-3-carboxylic acid methyl ester (1.97 g, 90%) as a white solid.

1. temperatureThe resulting solution was heated
2. temperatureto reflux for 2 h
3. customThe cooled solution was evaporated to dryness
4. additionthe residue was treated with methanol (20 ml)
5. customThe resulting solution was evaporated to dryness