Acetone → Diethyl isopropylidenemalonate

Participants

Reaction Steps

A reaction mixture of 200 g (1.25 mol) of diethyl malonate, 159.51 g (1.56 mol) of acetic anhydride, 108.9 g (1.87 mol) of acetone, and 25.5 g (0.187 mol) of zinc chloride placed in a 1000 ml round bottom flask was allowed to reflux for 20 hours. The reaction mixture was cooled, diluted with 200 ml of benzene, and the resulting mixture was washed with water (4×250 ml). The combined aqueous layer was extracted with benzene (2×50 ml) and the organic layers were combined. After removing benzene in vacuo, the mixture was distilled twice (Vigreux distilling column--10") to afford 111.8 g (44.7%--crude) of diethyl isopropylidenemalonate contains a trace of diethyl malonate), b.p. 80° C./0.5 mm.

Provenance & Evidence