Hydrochloric Acid → Diallyl 2-[4-(methoxycarbonyl)phenyl]ethylmalonate

Participants

Reaction Steps

1.125 g (28.14 mmol) of sodium hydride are added in portions to a solution of 6.91 g (37.52 mmol) of diallyl malonate in 50 ml of dioxane at 0° C. (caution: evolution of hydrogen). After warming to room temperature, the mixture is stirred at 40° C. for 1 h. Then 4.56 g (18.76 mmol) of methyl 4-(2-bromoethyl)benzoate [CAS Reg. No. 136333-97-6], dissolved in 20 ml of dioxane, are slowly added dropwise at 40° C., and the reaction solution is stirred at 110° C. overnight. After cooling to room temperature, the reaction mixture is added to 1200 ml of water. Care must be taken during this that the pH remains <7 (if necessary, a few ml of 1 M hydrochloric acid are metered in until the pH is about 2). The mixture is then extracted three times with ethyl acetate, and the combined organic phases are washed with saturated sodium chloride solution and dried over sodium sulphate. After filtration, the solvent is evaporated to dryness in vacuo. Subsequently, excess diallyl malonate is removed by high vacuum distillation (boiling point: 57° C., 0.074 mbar). The distillation residue is purified by flash chromatography on silica gel (mobile phase: petroleum ether/ethyl acetate 10:1). 6.01 g (17.35 mmol, 92% of theory) of a colourless solid are obtained.

Provenance & Evidence