1,2-Dichloroethane → 4-(2-Chloro-ethoxy)-benzoic acid methyl ester

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Reaction Steps

4-hydroxybenzoic acid methyl ester (1.52 g, 10 mmol), anhydrous potassium carbonate (1.38 g, 10 mmol), 10 ml of dimethylsulfoxide, and 20 ml of 1,2-dichloroethane are combined and heated to reflux. HPLC shows the reaction is at equilibrium at about 1 hour. Therefore, another equivalent of potassium carbonate is added. After the second addition of potassium carbonate, the ratio of product to bis alkylated biproduct is greatly enhanced. The reaction mixture is cooled to room temperature and diluted with 30 ml of water. The mixture is stirred then the layers separated. The organic layer is back extracted with 20 ml of brine and then filtered through sodium sulfate. The filtrate is concentrated in vacuo at about 60° C. to a yellow green oil which solidifies on cooling. This crude product is redissolved in 12 ml of hot methanol and water is added (total of 6 ml) dropwise until crystals appear. The crystallization is allowed to continue for one hour with cooling. The precipitate is filtered and rinsed with 12 ml of 1:1 methanol:water. The filter cake is dried in vacuo at about room temperature to give 2.00 g of product. (93.5%). HPLC.

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