General procedure for the synthesis of 1-azabicyclo[2.2.2]octane-4-carboxylic acid hydrochloride from 4-cyanoquinuclidine: Quinuclidine-4-carbonitrile (4 g, 29.4 mmol) was dissolved in 30 mL of aqueous 6N hydrochloric acid and the reaction was stirred under refluxing conditions for 16 hours. Upon completion of the reaction, the reaction mixture was cooled and subsequently evaporated to dryness under reduced pressure. The resulting solid was ground with 20% ether-hexane mixture to give the final quinuclidine-4-carboxylic acid hydrochloride (5.5 g, quantitative yield).
