反应详情

To a mixture of 1H-pyrazol-3-ylamine (8.3 g, 100 mmol), acetone (7.4 mL, 100 mmol) and acetic acid (12 mL, 200 mmol) in THF (280 mL) was added, in portions, sodium triacetoxyborohydride (27 g, 120 mmol) while cooling with an ice-water bath. The mixture was stirred at room temperature for 1 h and then at 50° C. for 3 h. After cooling to room temperature, 10 N NaOH (40 mL) was added dropwise, and stirred gently for 1 h. The clear solution was isolated with decantation. The gummy residue was washed with THF (2×50 mL). All the THF solutions were combined and concentrated. The residue was purified by silica gel column chromatography (EtOAc), affording isopropyl-(1H-pyrazol-3-yl)-amine (8.5 g, 68%) as a colorless oil. 1H NMR (300 MHz, CDCl3): δ 7.34 (d, 1H), 5.62 (d, 1H), 3.58 (m, 1H), 1.22 (d, 6H).

1. temperaturewhile cooling with an ice-water bath
2. waitat 50° C. for 3 h
3. temperatureAfter cooling to room temperature
4. stirringstirred gently for 1 h
5. customThe clear solution was isolated with decantation
6. washThe gummy residue was washed with THF (2×50 mL)
7. concentrationconcentrated
8. customThe residue was purified by silica gel column chromatography (EtOAc)