Reaction Steps
To a solution of 7H-spiro[benzofuro[4,5-c][1,2,5]oxadiazole-8,3′-indolin]-2′-one (0.400 g, 1.4 mmol) in anhydrous N,N-dimethylformamide (7 mL) was added sodium hydride (60% w/w dispersion in mineral oil, 0.086 g, 3.6 mmol) at 0° C. and the mixture was stirred for 20 minutes. 5-(Benzyloxy)-2-(chloromethyl)pyridine (0.44 g, 1.9 mmol) was added and the reaction mixture was stirred at ambient temperature for 19 h. Potassium iodide (˜10 mg, catalytic amount) was added and the reaction mixture was stirred at 60° C. for 2 h, at ambient temperature for 43 h, at 60° C. for 7 h and at ambient temperature for 3 days. Saturated aqueous ammonium chloride (7 mL) and water (30 mL) were added and the mixture was extracted with ethyl acetate (3×10 mL). The combined organic extracts were washed with water (2×20 mL) and brine (20 mL), dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography and eluted with hexanes/ethyl acetate (3/2), followed by trituration in hexanes to afford 1′-{[5-(benzyloxy)pyridin-2-yl]methyl}spiro[furo[3,2-e][2,1,3]benzoxadiazole-8,3′-indol]-2′(1′H)-one (0.034 g, 5%) as a pale yellow solid: mp 209-212° C.; 1H NMR (300 MHz, CDCl3) δ 8.36 (d, J=2.7 Hz, 1H), 7.83 (d, J=9.6 Hz, 1H), 7.50 (d, J=8.7 Hz, 1H), 7.45-7.23 (m, 8H), 7.18 (d, J=7.5 Hz, 1H), 7.03 (t, J=7.5 Hz, 1H), 6.92 (J=7.8 Hz, 1H), 5.39 (d, J=15.9 Hz, 1H), 5.27 (d, J=9.6 Hz, 1H), 5.11 (s, 2H), 4.99 (d, J=9.3 Hz, 1H), 4.87 (d, J=15.9 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ176.0, 163.0, 154.4, 148.3, 147.1, 144.9, 142.2, 137.8, 136.0, 129.8, 129.7, 128.7, 128.3, 127.6, 123.7, 123.6, 122.4, 122.3, 121.9, 119.3, 110.2, 107.0, 82.0, 70.4, 57.4, 46.0; MS (ES+) m/z 477.2 (M+1).
