反应详情

A suspension of tert-butyl 4-chloro-3-(chloromethyl)-2-butenoate (1.2 g, 5.3 mmol), potassium carbonate (4.0 g, 29 mmol), diethylhydrazine dihydrochloride (1.3 g, 8.0 mmol) and potassium iodide (0.86 g, 5.2 mmol) in acetonitrile was stirred at room temperature for 3 days. The mixture was filtered through celite, concentrated and purified by flash chromatography on silica gel eluting ethyl acetate:hexane (20:80, v;v) to give the tert-butyl (1,2-diethyl-4-pyrazolidinylidene)acetate (1.05 g, 82%) as an oil, MS (M+H)+=241.

1. filtrationThe mixture was filtered through celite,
2. concentrationconcentrated
3. custompurified by flash chromatography on silica gel
4. washeluting ethyl acetate:hexane (20:80, v;v)