3-[4-(4-Pyridinyl)butyl]-9-oxa-3,7-diazabicyclo[3.3.1]nonane (0.25 g, 0.96 mmol, from step (ii) above), tert-butyl 2-bromoethylcarbamate (0.26 g, 0.98 mmol, see Preparation R above) and K2CO3 (0.4 g, 2.9 mmol) were mixed in CH3CN (10 mL) and stirred at 50° C. overnight. The reaction mixture was filtered, evaporated and purified by chromatography on silica (DCM:6% MeOH (satd. with NH3)). Additional purification by extraction with ether:KHSO4, basification of the organic phase and extraction with DCM gave the title compound in 51% yield.
