Acetone → Diethyl isopropylidenemalonate

Temperature

90 °C

Diethyl isopropylidenemalonate was prepared according to the procedure of E. L. Eliel, R. O. Hutchins, and Sr. M. Knoeber, Organic Synthesis Coll. Vol. VI, 442, 1988, with following modifications. A mixture of acetone (54 g, 0.93 mol, Mallinckrodt), diethyl malonate (100 g, 0.62 mol, Aldrich), acetic anhydride (80 g, 0.78 mol, Mallinckrodt), and zinc chloride (12.5 g, 0.78 mol, Aldrich) was refluxed (90° C. oil bath) for 18 h while protected from moisture. The reaction solution was diluted with dichloromethane (500 ml) and washed with cold water (3×50 ml). The aqueous washes were combined and extracted with dichloromethane. All dichloromethane layers were combined and concentrated by spin evaporation in vacuo. The residual oil was distilled under vacuum and the fractions boiling at 102°-138° C. at 12 Torr were combined with the pot residue and heated for 6 h with a 200° C. oil bath. The dark oil was redistilled to give 40.1 g (32%) of diethyl isopropylidenemalonate as a clear oil: b.p., 110°-115° C./12 mm Hg: NMR (DMSO-d6): d 4.19 (q, 4 H, J=7.2 Hz, OCH2), 2.03 (s, 6 H, =C(CH3)2), 2.25 (t, 6 H, J=7.2 Hz, CH2).

1. customDiethyl isopropylidenemalonate was prepared
2. customKnoeber, Organic Synthesis Coll
3. washwashed with cold water (3×50 ml)
4. extractionextracted with dichloromethane
5. concentrationconcentrated by spin evaporation in vacuo
6. distillationThe residual oil was distilled under vacuum
7. temperatureheated for 6 h with a 200° C. oil bath
8. distillationThe dark oil was redistilled

ORD record

ord-8c5fe3e516b64cbbb2f6474596ad2a0a

Source dataset

uspto-grants-1998_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05719186