反应详情

Acetic anhydride (27.2 mL, 243.89 mmol) was dropwise added to a stirred suspension of 1,3-dimethyl-pyrazol-4-amine hydrochloride (12 g, 81.30 mmol) and potassium acetate (7.98 g, 81.30 mmol) in EtOAc (250 mL) at 25° C. The suspension was stirred for 1 hour and the insoluble was removed by filtration. After evaporation of the solvent, the resulting crude material was purified by chromatography on silica gel eluting with 0% to 10% of MeOH in DCM. After evaporation of the solvent, the residue was triturated in Et2O. The resulting precipitate was collected by filtration, washed with Et2O and dried to a constant weight to afford N-(1,3-dimethylpyrazol-4-yl)acetamide. The filtrate was concentrated and purified by flash chromatography on silica gel eluting with 0 to 10% MeOH in DCM. The solvent was evaporated to dryness to afford more N-(1,3-dimethylpyrazol-4-yl)acetamide. The two batches were combined to give N-(1,3-dimethylpyrazol-4-yl)acetamide (6.40 g, 51.4%) as a off-white solid.

1. customthe insoluble was removed by filtration
2. customAfter evaporation of the solvent
3. customthe resulting crude material was purified by chromatography on silica gel eluting with 0% to 10% of MeOH in DCM
4. customAfter evaporation of the solvent
5. customthe residue was triturated in Et2O
6. filtrationThe resulting precipitate was collected by filtration
7. washwashed with Et2O
8. customdried to a constant weight