Reaction Steps
rac-(4aR,13bS)-9-(4-Fluorophenyl)-13b-(pyridin-2-ylmethyl)-1,2,4,4a,5,6,7,13b-octahydro spiro[benzo[3,4]cyclohepta[1,2-d]imidazo[1,5-a]pyridine-3,2′-[1,3]dioxolane] (148, R1=4-Fluorophenyl, R2=Pyridin-2-ylmethyl) (0.380 g, 0.786 mmol) in 1,4-dioxane (8 mL) and water (2 mL) was treated with 6 N hydrochloric acid (0.52 mL, 3.1 mmol) then stirred at rt for about 4 h. Water (1 mL) was added and the mixture was stirred for about 12 h. Sat. aq. NaHCO3 (˜10 mL) and EtOAc (20 mL) were added to the mixture then the layers were separated. The organic layer was washed with brine (˜15 mL) then dried over MgSO4, filtered and concentrated to yield rac-(4aR,13bS)-9-(4-fluorophenyl)-13b-(pyridin-2-ylmethyl)-4,4a,5,6,7,13b-hexahydro-1H-benzo[3,4]cyclohepta[1,2-d]imidazo[1,5-a]pyridin-3(2H)-one (149, R1=4-Fluorophenyl, R2=Pyridin-2-ylmethyl) (0.323 g, 94%); LC/MS, method 3, Rt=2.30 min, MS m/z 440 (M+H)+. 1H NMR (400 MHz, DMSO) δ 8.38-8.36 (m, 1H), 8.18 (s, 1H), 7.96-7.90 (m, 3H), 7.75 (s, 1H), 7.43-7.39 (m, 1H), 7.27-7.19 (m, 2H), 7.08-7.04 (m, 1H), 6.59 (d, J=7.8 Hz, 1H), 3.70 (d, J=13.6 Hz, 1H), 3.45-3.38 (m, 2H), 3.20-3.02 (m, 2H), 2.69-2.62 (m, 1H), 2.29-1.87 (m, 7H), 1.72-1.63 (m, 1H), 1.46-1.32 (m, 1H).
