1-Adamantanecarboxylic acid chloride

A solution of 21.7 g (0.11 mole) 1-adamantanecarboxylic acid chloride in 100 ml ether was added to a solution of 19.4 g (0.22 mole) 2-dimethylaminoethanol in 200 ml ether. The reaction mixture was stirred overnight at room temperature. Then additional 15.0 g (0.17 mole) 2-dimethylaminoethanol was added and the reaction mixture again stirred overnight. The reaction mixture was poured into 300 ml water and treated with 20 ml of 10% NaOH solution. From the ether layer was recovered 23.0 g of 2-dimethylaminoethyl 1-adamantanecarboxylate as oil. 

Japanese patent [21] describes a method of synthesis of 4-carbamoyl-5-(adamantoyloxy)-imidazole (9) with antibacrterial and antiinflammatory activities. It consists in interaction of 4-carbamoyl-5-hydroxyimidazole with adamantanecarboxylic acid chloride in the absolute pyridine environment ... 

As an alternative purification procedure, the checkers have esterified the crude acid by refluxing it for 2 hours with three times its weight of methanol and 2 ml. of 98% sulfuric acid. The solution is poured into 10 volumes of water and extracted with the minimum amount of chloroform required to give a clean separation of layers. The chloroform solution is washed with water, dried over calcium chloride, and distilled from a Claisen flask with an indented neck. Methyl 1-adamantanecarboxylate is collected at 77-79° (1 mm.) m.p. 38-39°. Hydrolysis of the ester with the calculated amount of 1A potassium hydroxide followed by acidification yields 1-adamantanecarboxylic acid m.p. 175-176.5° 90% overall recovery. 

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