Boron trifluoride etherate → p-Aminophenylacetic acid ethyl ester

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Reaction Steps

A solution of 8.2 g. of 4-aminophenylacetic acid, 150 ml. of absolute ethanol, and 3 ml. of boron trifluoride etherate is heated to reflux for 15 hours. The solution is concentrated by distillation and then evaporated to dryness in vacuo. The residue is dissolved in ethyl ether, washed with aqueous sodium bicarbonate dried and evaporated to yield ethyl 4-aminophenylacetate. A mixture of 5.0 g. of this amine, 9.4 g. of 15-(trifluoromethyl)pentadecyl bromide, 4.2 g. of anhydrous potassium carbonate and 40 ml. of hexamethylphosphoramide is heated at 80° C. for 7 hours. The mixture is then cooled, diluted with water, and extracted with ethyl ether. The ether extracts are washed with water, dried and evaporated. The residue is recrystallized from a mixture of chloroform and hexane, yielding ethyl 4-[15-(trifluoromethyl)pentadecylamino]phenylacetate. A mixture of 6.0 g. of this ester, 7.0 g. of potassium hydroxide and 100 ml. of ethanol-water is heated to reflux for 4 hours. While hot, the mixture is adjusted to pH 7 with concentrated hydrochloric acid. The mixture is diluted with water, cooled and filtered. Recrystallization of the precipitate yields the product as a white solid.

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