Reaction Steps
A solution of 1′-{[1-(1-methylethyl)piperidin-4-yl]methyl}-5,6-dihydrospiro[benzo-[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one (0.21 g, 0.49 mmol) and 4 M hydrochloric acid in 1,4-dioxane (0.50 mL, 2.0 mmol) in methanol (1.5 mL) was stirred at ambient temperature for 30 min. The solvent was removed under reduced pressure, the residue was suspended in ethyl acetate/hexanes and the resulting precipitate was collected by filtration. The precipitate was dried to afford 1′-{[1-(1-methylethyl)piperidin-4-yl]methyl}-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one hydrochloride (0.17 g, 76%) as a colorless powder: mp 167° C. (dec.) (hexanes); 1H NMR (300 MHz, CD3OD) δ 7.36 (ddd, J=7.8, 7.2, 1.2 Hz, 1H), 7.19-7.08 (m, 3H), 6.48 (s, 1H), 6.33 (s, 1H), 4.83 (d, J=9.3 Hz, 1H), 4.67 (d, J=9.3 Hz, 1H), 4.51 (t, J=8.6 Hz, 2H), 3.80 (dd, J=14.3, 7.5 Hz, 1H), 3.73 (dd, J=14.3, 7.1 Hz, 1H), 3.54-3.42 (m, 3H), 3.07-2.96 (m, 4H), 2.31-2.16 (m, 1H), 2.09-1.98 (m, 2H), 1.76-1.60 (m, 2H), 1.35 (d, J=6.6 Hz, 6H); 13C NMR (75 MHz, CD3OD) δ180.4, 163.3, 162.9, 143.8, 134.0, 130.1, 124.9, 124.8, 121.5 (2C), 120.1, 110.4, 93.7, 81.8, 73.5, 59.7, 59.3, 49.5, 45.8, 34.1, 29.9, 28.7, 28.67, 17.0; MS (ES+) m/z 419.3 (M+1); Anal. Calcd. for C26H30N2O3.HCl.2H2O: C, 63.60; H, 7.18; N, 5.71. Found: C, 63.80; H, 6.83; N, 5.67.
