To a stirred solution of 9-(quinoxalin-2-yl)-2,9-diazaspiro[5.5]undecan-1-one (0.035 g, 0.12 mmol) in dry THF (4.0 mL), NaH (0.014 g, 0.36 mmol) was added at rt and the mixture was stirred for 10 min. 3-(3-Chloromethyl-phenyl)-pyridine (0.05 g, 0.24 mmol) was then added and the reaction mixture was heated to 60° C. for 6 h. The mixture was quenched with 1 ml saturated aqueous NH4Cl solution, diluted with 50 ml water and the resulting mixture was extracted with ethyl acetate (100 mL). The organic layer was washed with water and brine. The organic layer was dried over Na2SO4, filtered and concentrated to obtain the crude product. Preparative HPLC purification furnished the title compound as a pale yellow sticky solid (0.025 g, 46%). [1H-NMR (CDCl3, 300 MHz): δ 8.84-8.81 (m, 1H), 8.66-8.58 (m, 2H), 7.92-7.81 (m, 2H), 7.72-7.65 (m, 1H), 7.35-7.61 (m, 6H), 4.68 (s, 2H), 4.31-4.20 (m, 2H), 3.70-3.55 (m, 2H), 3.31 (t, 2H), 2.43-2.29 (m, 2H), 1.96-1.82 (m, 4H), 1.75-1.63 (dt, 2H); HPLC RtA=4.635 min (96%); LCMS RtC=0.395, [M+H]+=464.0].
