反应详情

温度

-78 °C

In an oven-dried flask, 4-nitro-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-pyrazole (1.5192 g, 6.2432 mmol) was dissolved in 20 mL THF and cooled at −78° C. To this solution was slowly added 1.0M lithium hexamethyldisilazide in tetrahydrofuran (7.5 mL, 7.5 mmol). After stirring for 40 minutes at −78° C., a solution of iodine (1.7602 g, 6.9351 mmol) in 8 mL THF was slowly added. The reaction mixture was kept at −78° C. for an additional 1.5 hours, and then quenched with saturated aqueous ammonium chloride and warmed to room temperature. The reaction mixture was partitioned between ethyl acetate and half-saturated aqueous Na2S2O3. The organic layer was dried with magnesium sulfate, filtered, and evaporated in vacuo. The crude product was purified via flash chromatography on silica gel (0 to 15% ethyl acetate in heptanes) to yield 2.2349 g (97%) of 5-iodo-4-nitro-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-pyrazole. 1H NMR (400 MHz, DMSO-d6) δ: 8.48 (s, 1H), 5.59 (s, 2H), 3.61 (t, J=8.0, 2H), 0.86 (t, J=8.0, 2H), −0.04 (s, 9H).

1. waitThe reaction mixture was kept at −78° C. for an additional 1.5 hours
2. customquenched with saturated aqueous ammonium chloride
3. temperaturewarmed to room temperature
4. customThe reaction mixture was partitioned between ethyl acetate and half-saturated aqueous Na2S2O3
5. dry with materialThe organic layer was dried with magnesium sulfate
6. filtrationfiltered
7. customevaporated in vacuo
8. customThe crude product was purified via flash chromatography on silica gel (0 to 15% ethyl acetate in heptanes)