Reaction Steps
To a suspended mixture of 1′-[(4-bromo-2-thienyl)methyl]spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (0.456 g, 1.0 mmol) and zinc cyanide (0.117 g, 1.0 mmol) in anhydrous N,N-dimethylformamide (5 mL) was added tetrakis(triphenylphosphine)palladium (0.04 g, 0.03 mmol). The reaction mixture was put into a microwave reactor set at 100 W at 133° C. for 7 min. The solid was filtered and washed with ethyl acetate (40 mL). The filtrate was concentrated in vacuo to dryness. The residue was purified by column chromatography with ethyl acetate in hexanes (10% to 30% gradient) to give 5-[(2′-oxospiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-1′(2′H)-yl)methyl]thiophene-3-carbonitrile (0.25 g, 62%) as a colorless solid: mp 207-209° C. (dichloromethane/hexane); 1H NMR (300 MHz, DMSO-d6) δ8.48 (d, J=1.3 Hz, 1H), 7.63 (d, J=1.3 Hz, 1H), 7.33 (dd, J=7.8, 1.1 Hz, 1H), 7.23-7.19 (m, 2H), 7.06 (d, J=7.4, 0.8 Hz, 1H), 6.71 (s, 1H), 6.15 (s, 1H), 5.93 (d, J=1.5 Hz, 2H), 5.14 (d, J=4.6 Hz, 2H), 4.81 (d, J=9.4 Hz, 1H), 4.69 (d, J=9.4 Hz, 1H); 13C NMR (75 MHz, DMSO-d6) δ176.5, 155.4, 148.3, 141.7, 141.5, 141.3, 137.8, 131.5, 128.8, 127.9, 123.7, 123.3, 119.4, 115.1, 109.3, 108.7, 102.8, 101.4, 93.3, 79.7, 57.3, 37.9; MS (ES+) m/z 403.2 (M+1).
