反应详情

To refluxing solution of sodium ethoxide (51.2 g, 0.75 mmol) in ethanol (170 ml) was added dropwise over 30 minutes a solution of 2-pentanone (59 g, 0.68 mol) in diethyl oxalate (99 g, 0.68 mol). The resulting turbid yellow mixture was refluxed further for 2 hours, cooled to room temperature, poured over 500 g ice with stirring and adjusted to pH 1-2 with concentrated sulfuric acid (~40 ml). The organic phase was extracted with benzene (3×300 ml), washed once with saturated aqueous sodium chloride and dried over anhydrous sodium sulfate, before being filtered, concentrated, and fractionally distilled at 0.1 mm Hg to give 48.2 g (38%) of the title compound as a yellow liquid; b.p. 85°-95° C.

1. temperatureThe resulting turbid yellow mixture was refluxed further for 2 hours
2. extractionThe organic phase was extracted with benzene (3×300 ml)
3. washwashed once with saturated aqueous sodium chloride
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationbefore being filtered
6. concentrationconcentrated
7. distillationfractionally distilled at 0.1 mm Hg