Reaction Steps
To a solution of 1′-(3-aminopropyl)-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one (0.20 g, 0.59 mmol) in anhydrous dichloromethane (10 mL) was added triethylamine (0.10 mL, 0.71 mmol) followed by 2-(trifluoromethoxy)benzoyl chloride. The reaction mixture was stirred at ambient temperature for 20 h and concentrated in vacuo. The residue was purified by column chromatography to afford N-[3-(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)propyl]-2-(trifluoromethoxy)benzamide (0.21 g, 67%) as a colorless foam: mp 65-70° C.; 1H NMR (300 MHz, CDCl3) δ 7.81 (dd, J=7.6, 1.7 Hz, 1H), 7.47 (ddd, J=9.4, 7.6, 1.5 Hz, 1H), 7.39-7.30 (m, 3H), 7.20 (d, J=6.9 Hz, 1H), 7.09 (dd, J=7.5, 7.5 Hz, 1H), 6.95 (d, J=7.9 Hz, 1H), 6.47 (s, 1H), 6.41 (s, 1H), 4.90 (d, J=9.0 Hz, 1H), 4.67 (d, J=9.0 Hz, 1H), 4.53 (t, J=8.6 Hz, 1H), 4.02-3.83 (m, 2H), 3.58-3.33 (m, 2H), 2.99 (t, J=8.6 Hz, 2H), 2.05-2.01 (m, 2H); 13C NMR (75 MHz, CDCl3) δ 179.0, 164.9, 161.9, 161.3, 145.7, 141.8, 132.8, 131.8, 130.7, 129.3, 128.9, 127.3, 124.1, 123.7, 121.5, 120.3 (d, JC-F=259.2 Hz), 120.0, 119.8, 118.7, 108.4, 93.3, 80.5, 72.4, 57.8, 37.1, 36.1, 29.0, 27.0; MS (ES+) m/z 524.5 (M+1).
