Reaction Steps
To a suspension of 2′-oxo-1′-(pyridin-2-ylmethyl)-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indole]-5′-carbonitrile (0.24 g, 0.57 mmol) in ethanol (20 mL) was added 3 M aqueous sodium carbonate (2 mL) and 30% w/w aqueous hydrogen peroxide (2 mL). The reaction mixture was stirred at ambient temperature for 16 h and concentrated in vacuo. The residue was triturated in water to afford 2′-oxo-1′-(pyridin-2-ylmethyl)-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indole]-5′-carboxamide (0.23 g, 93%) as a colorless solid: mp 220-222° C. (water); 1H NMR (300 MHz, CDCl3) δ 8.46-8.42 (m, 1H), 7.82 (s, 1H), 7.81-7.74 (m, 2H), 7.65 (d, J=1.5 Hz, 1H), 7.38 (d, J=7.8 Hz, 1H), 7.28 (dd, J=7.0, 5.0 Hz, 1H), 7.19 (s, 1H), 6.98 (d, J=8.3 Hz, 1H), 6.50 (s, 1H), 6.33 (s, 1H), 5.14-4.97 (ABq, 2H), 4.81-4.68 (ABq, 2H), 4.19-4.06 (m, 4H); 13C NMR (75 MHz, CDCl3) δ 177.6, 167.6, 155.4, 155.1, 149.7, 145.7, 144.7, 138.3, 137.6, 132.4, 129.4, 129.2, 123.3, 123.3, 122.3, 121.6, 112.1, 109.3, 99.2, 79.8, 64.7, 64.1, 57.7, 45.3; MS (ES+) m/z 429.9 (M+1).
