反应详情

温度

-78 °C

To a stirring solution of 7-bromo-3-(2,4-dichloro-phenyl)-2,6-dimethyl-pyrazolo[5,1-b]oxazole (710 mg, 1.972 mmol) in THF (15.5 ml) under N2 at −78° C. is added n-butyllithium (0.789 ml, 1.972 mmol) dropwise; the temperature is maintained below −70° C. for the addition and then the reaction mixture is stirred for 5 mins at −78° C. before the addition of di-tert-butyl azodicarboxylate (545 mg, 2.366 mmol) in THF (1.5 ml); the temperature is maintained below −60° C. for the period of the addition. After stirring at −78° C. for 30 mins, the reaction is quenched with sat. ammonium chloride solution and allowed to warm to RT. Ammonium chloride solution (sat.) is added and the mixture is extracted with EtOAc (2×100 ml). The combined organics extracts are washed with brine, dried over MgSO4 and concentrated in vacuo. The crude product is purified ISCO chromatography eluting (0 to 100%) EtOAci iso-hexane on a 40 g SiO2 cartridge to give the title compound as an orange solid; MS: m/z 511.22 [M+H]+

1. temperaturethe temperature is maintained below −70° C. for the addition
2. temperaturethe temperature is maintained below −60° C. for the period of the addition
3. customthe reaction is quenched with sat. ammonium chloride solution
4. temperatureto warm to RT
5. additionAmmonium chloride solution (sat.) is added
6. extractionthe mixture is extracted with EtOAc (2×100 ml)
7. washThe combined organics extracts are washed with brine
8. dry with materialdried over MgSO4
9. concentrationconcentrated in vacuo
10. customThe crude product is purified ISCO chromatography
11. washeluting (0 to 100%) EtOAci iso-hexane on a 40 g SiO2 cartridge