反应详情

温度

-10 °C

A mixture of ethyl 3-amino-pyrazole-4-carboxylate (6.4 g, 40 mmole) and diiodomethane (200 g) was cooled to −10° C. Isoamyl nitrite (24 mL, 180 mmole) was added via a syringe over 30 minutes. The mixture was allowed to warm up to ambient temperature and then stirred at 100° C. for 2 hours. After cooling to room temperature, the mixture was concentrated and the residue was dissolved in ethyl acetate (200 mL) and washed with 0.5 M aqueous sodium metasulfite solution (2×70 mL), 1 N HCl and brine. The organic solution was dried with magnesium sulfate and concentrated. The crude product was purified on a silica gel column eluting with 15% ethyl acetate in hexane to provide the title compound. MS (DCI) m/e 266.9 (M+H)+, 283.9 (M+NH4)+.

1. temperatureto warm up to ambient temperature
2. temperatureAfter cooling to room temperature
3. concentrationthe mixture was concentrated
4. dissolutionthe residue was dissolved in ethyl acetate (200 mL)
5. washwashed with 0.5 M aqueous sodium metasulfite solution (2×70 mL), 1 N HCl and brine
6. dry with materialThe organic solution was dried with magnesium sulfate
7. concentrationconcentrated
8. customThe crude product was purified on a silica gel column
9. washeluting with 15% ethyl acetate in hexane