Reaction Steps
A mixture of 4′-(benzylamino)-1′-{[3-(trifluoromethyl)pyridin-2-yl]methyl}-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one (0.251 g, 0.45 mmol) and palladium hydroxide on carbon (0.251 g, 20 dry wt %, contains ˜50% water, 0.18 mmol), methanol (20 mL), glacial acetic acid (1 drop, catalytic amount) was placed under an atmosphere of hydrogen (1 atm) and stirred at ambient temperature for 16 h. Further, palladium hydroxide on carbon (0.100 g, 20 dry wt %, contains ˜50% water, 0.072 mmol) and acetic acid (1 drop, catalytic amount) were added, the reaction mixture was again placed under an atmosphere of hydrogen (1 atm) and allowed to react at ambient temperature for 72 h. The reaction mixture was filtered through a pad of diatomaceous earth and the pad was washed with ethyl acetate (50 mL). The filtrate was washed with water (100 mL) and brine (100 mL). The organic phase was dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography and eluted with a 0% to 25% gradient of ethyl acetate in dichloromethane, to yield 4′-amino-1′-{[3-(trifluoromethyl)pyridin-2-yl]methyl}-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one (0.070 g, 33%) as a colorless solid: mp 243-245° C.; 1H NMR (300 MHz, DMSO-d6) δ 8.68 (d, J=4.6 Hz, 1H), 8.25 (d, J=7.9 Hz, 1H), 7.58 (dd, J=7.7 Hz, J=5.0 Hz, 1H), 6.91 (dd, J=8.0 Hz, J=8.0 Hz, 1H), 6.54 (d, J=12.1 Hz, 1H), 6.33 (d, J=8.2 Hz, 1H), 6.08 (d, J=7.6 Hz, 1H), 5.14 (ABq, 2H), 4.71 (ABq, 2H), 4.52 (s, 2H), 4.17 (m, 4H); 13C NMR (75 MHz, CDCl3) δ 178.0, 154.9, 152.6, 152.4, 144.7, 142.9, 142.8, 138.8, 134.2, 134.1, 129.4, 122.0, 118.6, 114.5, 112.8, 111.3, 99.0, 77.2, 64.5, 63.9, 57.2, 42.4; MS (ES+) m/z 469.9 (M+1).
