Reaction Steps
Following the procedure as described in EXAMPLE 12 and making non-critical variations using ammonia in dry dichloromethane to replace cyclohexanemethylamine, and 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoic acid to replace 3-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoic acid, 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzamide was obtained (81%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ7.78 (d, J=7.9 Hz, 2H), 7.34 (d, J=7.9 Hz, 2H), 7.20-7.07 (m, 2H), 6.99 (t, J=7.4 Hz, 1H), 6.85 (s, 1H), 6.71 (d, J=7.6 Hz, 1H), 6.41 (br s, 1H), 6.35 (br s, 1H), 6.20 (s, 1H), 4.94 (ABq, 2H), 4.78 (ABq, 2H), 4.46 (t, J=8.5 Hz, 2H), 2.91 (t, J=8.5 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ177.6, 168.7, 161.5, 160.9, 141.4, 139.3, 132.7, 132.1, 128.4, 127.8, 127.0, 123.6, 123.3, 119.6, 118.4, 108.8, 92.8, 80.2, 72.0, 57.3, 43.4, 28.6; MS (ES+) m/z 413.1 (M+1).
