反应详情

tert-butyl 5-chloro-1-(4-methoxycarbonylphenyl)pyrazole-4-carboxylate (Intermediate #9) (2.016 g, 6.0 mmol) was dissolved in butyronitrile (30 mL), potassium carbonate (2.48 g, 18 mmol) and propanethiol (678 μL, 7.5 mmol) were added and the mixture heated to reflux for 5 h. Ethyl acetate (150 mL) was added and the mixture washed with water (4×25 mL), dried (MgSO4) and evaporated under reduced pressure. The residue was purified by chromatography on silica gel (120 g silica 0-25% EtOAc/isohexane) to give the title compound as a clear pale yellow oil that slowly crystallised on standing to a white solid. (2.01 g, 89%)

1. temperaturethe mixture heated
2. temperatureto reflux for 5 h
3. washthe mixture washed with water (4×25 mL)
4. dry with materialdried (MgSO4)
5. customevaporated under reduced pressure
6. customThe residue was purified by chromatography on silica gel (120 g silica 0-25% EtOAc/isohexane)