A solution of 6-butyl-8-fluoroquinoline (for example, as prepared for Intermediate 2) (14.4 g, 70.9 mmol) in NMP (20 ml) was added to a mixture of tert-butyl-4-hydroxy-1-piperidinecarboxylate (commercially available, for example, from Aldrich) (21.6 g, 108 mmol) and sodium tert-butoxide (10.4 g, 108 mmol) in NMP (75 ml), and the resulting mixture was stirred at 140° C. for approximately 90 min and then allowed to cool overnight. The reaction mixture was treated with ammonium chloride solution and extracted with EtOAc (×2). The combined organic extracts were washed with water, dried (MgSO4), filtered and evaporated to dryness. The residue was purified by flash chromatography eluting with DCM-EtOAc (1:0 to 1:1) and then twice by Flashmaster chromatography eluting with DCM-EtOAc (1:0 to 3:1) over 40 min to give the title compound (22 g). LCMS RT=3.49 min, ES+ve m/z 385 [M+H]+
