Dimethyl malonate → 1,1-Dimethyl 2-ethenylcyclopropane-1,1-dicarboxylate

Temperature

60 °C

To a solution of 36.6 g (1.6 g-atom) of sodium in 500 ml of anhydrous ethanol was added 105.5 g (0.80 mol) of dimethyl malonate. After several minutes, while maintaining the temperature at 60° C., 250 ml anhydrous methanol was added to solubilize the precipated sodium malonate salt. The freshly prepared disodiomalonate methanol solution was added to 100.0 g (0.80 mol) trans 1,4-dichlorobutene-2 heated to 60°-70° C. at a rate to allow a gentle reflux in the condenser. When the addition was completed, the reaction mixture was refluxed with stirring for an additional 4 hours. The reaction mixture was then cooled to ambient temperature, filtered and the resulting filtrate concentrated. Distillation of the crude product under reduced pressure afforded 82 g (44.5%) of the desired product dimethyl 2-vinylcyclopropane-1,1-dicarboxylate. B.p. 73°-78° at 1.25 mm Hg; nD24 1.4612; [lit. B.p. 71°- 73° (1 mm); nD25 1.4602].

1. waitAfter several minutes
2. temperatureheated to 60°-70° C. at a rate
3. temperaturea gentle reflux in the condenser
4. additionWhen the addition
5. temperaturethe reaction mixture was refluxed
6. temperatureThe reaction mixture was then cooled to ambient temperature
7. filtrationfiltered
8. concentrationthe resulting filtrate concentrated
9. distillationDistillation of the crude product under reduced pressure

ORD record

ord-a03383b0c0504cceb7a20be6c434e907

Source dataset

uspto-grants-1983_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04380656