Reaction Steps
A 50 mL round-bottom flask was charged with 1′-[(3-aminopyridin-2-yl)methyl]-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one hydrobromide (0.56 g, 1.0 mmol), methanesulfonyl chloride (0.12 g, 1.1 mmol), pyridine (0.25 g, 3.0 mmol) and dichloromethane (20 mL). The reaction mixture was stirred under nitrogen at ambient temperature for 16 h and diluted with dichloromethane (50 mL). The organic phase was washed with water (2×50 mL), dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography and eluted with a 0% to 100% gradient of ethyl acetate in dichloromethane, followed by recrystallization from methanol (10 mL) to afford N-{2-[(2′-oxo-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-1′(2′H)-yl)methyl]pyridine-3-yl}methanesulfonamide (0.18 g, 38%) as an off-white solid: 1H NMR (300 MHz, DMSO-d6) δ 9.64 (s, 1H), 8.27 (dd, J=4.6, 1.2 Hz, 1H), 7.78 (dd, J=8.0, 1.4 Hz, 1H), 7.34 (dd, J=8.0, 4.7 Hz, 1H), 7.21-7.10 (m, 2H), 6.96 (t, J=7.4 Hz, 1H), 6.77 (d, J=7.8 Hz, 1H), 6.48 (s, 1H), 6.46 (s, 1H), 5.17 (ABq, 2H), 4.73 (ABq, 2H), 4.18-4.05 (m, 4H), 3.14 (s, 3H); 13C NMR (75 MHz, DMSO-d6) δ 177.6, 154.9, 151.0, 147.1, 144.5, 143.2, 138.1, 134.5, 132.6, 132.2, 132.1, 129.0, 123.8, 123.2, 122.2, 112.3, 109.4, 99.0, 79.6, 64.6, 64.1, 57.8, 41.8, 40.6; MS (ES+) m/z 479.9 (M+1).
