Water → 1,3-Bis(phenylmethyl) 2-(2-methoxyethyl)propanedioate

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Reaction Steps

Dibenzyl malonate (28.43 g, 0.1 mole) was added dropwise over 1 hour to a stirred suspension of sodium hydride (3.15 g, 80% dispersion in oil; 0.105 mole) in dry tetrahydrofuran (100 ml) under nitrogen, the temperature being allowed to rise to 40° C. 2-Methoxyethyl bromide (13.9 g, 0.1 mole) was added to the resulting clear solution, which was stirred at room temperature for two hours, and then refluxed overnight. Water was added, and the mixture extracted with methylene chloride. The organic extract on washing with water, drying (MgSO4) and evaporation under vacuum gave a crude liquid (30.94 g). Chromatography on silica gel (700 g) eluting with a mixture of ether and hexane (2:8 by volume) gave 2-methoxyethyl-malonic acid dibenzyl ester as a colourless liquid (15.6 g). This was dissolved in dioxan (150 ml) and a solution of potassium hydroxide (2.55 g, 45.44 mmole) in water (40 ml) added at 0° C. with stirring. The mixture was stirred overnight at room temperature and the solvent was evaporated under vacuum. Water was added and the mixture was extracted with ether to remove unreacted diester. The aqueous phase was then acidified with 2N hydrochloric acid (50 ml) and extracted with ether. The organic extract on washing with water, drying (MgSO4) and evaporation under vacuum gave the mono-ester as a colourless oil (8.95 g, 78%).

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