反应详情

In ethanol (10 mL) was placed the tert-butylhydrazine hydrochloride (1.35 g, 10.8 mmol) and ethyl 2-((dimethylaminomethylene)-3-oxobutanoate (2.00 g, 10.8 mmol). The mixture warmed to reflux and stirred for 2 hrs, cooled to RT and stirred overnight. The mixture was evaporated at reduced pressure to give an oil which was dissolved in ether (25 mL) and washed successively with water (25 mL), saturated sodium bicarbonate (25 mL) and brine (25 mL), dried (Na2SO4 and evaporated at reduced pressure to give an oil. The oil was purified by chromatography (Biotage S1-25 column, 10-40% ethyl acetate/Hex 750 mL) to give ethyl 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylate (1.48 g, 65% yield) as an oil. MS (ESI) m/z: 211.0 (M+H+).

1. temperatureThe mixture warmed
2. temperatureto reflux
3. stirringstirred overnight
4. customThe mixture was evaporated at reduced pressure
5. customto give an oil which
6. washwashed successively with water (25 mL), saturated sodium bicarbonate (25 mL) and brine (25 mL)
7. dry with materialdried (Na2SO4
8. customevaporated at reduced pressure
9. customto give an oil
10. customThe oil was purified by chromatography (Biotage S1-25 column, 10-40% ethyl acetate/Hex 750 mL)