alpha-Naphthaleneacetic acid, ethyl ester → Diethyl 2-(1-naphthyl)malonate

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A mixture of 103.9 g (485 mmol) of ethyl naphthalene-1-acetate and 430 ml of ethyl carbonate is stirred at 105° C., and a solution of sodium ethoxide (11 g (478 mmol) of sodium in 255 ml of absolute ethanol) is then added in such a way that the ethanol distils in the course of the introduction. The mixture is heated for a further 15 min. to distil the maximum amount of ethanol, the flask is rapidly cooled and the mixture is poured onto 300 g of crushed ice and 20 ml of concentrated hydrochloric acid. It is extracted with diethyl ether, the organic phase is dried over magnesium sulphate and filtered, and the solvent is evaporated under reduced pressure. An oil is obtained which crystallises in pentane in the cold. The crystals are separated by filtration, treated with vegetable charcoal in diethyl ether and filtered, the filtrate is evaporated and the residue is recrystallised in a 25:75 mixture of diethyl ether/pentane. 97 g (339 mmol) of crystals are obtained.

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