Ethyl 5-(1-Chloroethyl)-2-Furoate

Abstract

A mixture of 70 g (0.5 mole) of ethyl 2-furoate, 16 g of anhydrous zinc chloride, and 150 ml of chloroform (Note 1) was prepared in a 500-ml four-necked round-bottomed flask fitted with mercury-sealed stirrer, thermometer, dropping funnel, and gas-outlet tube. With continuous stirring the contents of the flask were cooled with a mixture of ice and salt to a temperature of from −1° to 0°, and 44 g (1 mole) of acetaldehyde (Note 2) was added at such a rate that the temperature of the mixture did not rise above 4–5° (30–40 minutes was required) (Note 3). When the whole of the acetaldehyde had been added, the dropping funnel was replaced by a bent tube which reached to the bottom of the flask, and with continued vigorous stirring a rapid stream of hydrogen chloride (which had passed through a wash bottle containing sulfuric acid) was passed through the mixture; the temperature of the mixture was maintained at not above 4–5° (Note 4). When saturation was reached (1–1.5 hours), a slower stream of hydrogen chloride was passed for one hour further, after which the temperature of the mixture was allowed to rise gradually (over a period of 45–50 minutes) to that of the room; stirring was continued further for 2.5–3 hours. The contents of the flask were then poured into a beaker containing 100 ml of ice water; the chloroform layer was separated, and the aqueous layer was extracted with 25 ml of chloroform, which was then added to the main product. The chloroform solution was washed 2–3 times with 100-ml portions of ice water with careful separation of the aqueous layer (Note 5). Solvent was distilled off under reduced pressure (water pump), and the residue was vacuum-distilled with collection of the liquid coming over at 117–121°/3 mm. Redistillation gave a substance boiling at 118–120°/3 mm (Note 6).