Reaction Steps
Following the procedure as described in EXAMPLE 12 and making non-critical variations using 4-ethylaniline to replace cyclohexanemethylamine, and 2-[(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, N-(4-ethylphenyl)-2-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzamide was obtained (87%) as a colorless solid: mp>230° C.; 1H NMR (300 MHz, DMSO-d6) δ10.50 (s, 1H), 7.68-7.55 (m, 3H), 7.49-7.35 (m, 2H), 7.23-7.10 (m, 5H), 6.99 (dd, J=7.5, 7.5 Hz, 1H), 6.88 (d, J=7.8 Hz, 1H), 6.51 (s, 1H), 6.39 (s, 1H), 5.15-4.99 (m, 2H), 4.83 (d, J=8.9 Hz, 1H), 4.68 (d, J=8.9 Hz, 1H), 4.46 (t, J=8.7 Hz, 2H), 2.99-2.85 (m, 2H), 2.54 (q, J=7.5 Hz, 2H), 1.14 (t, J=7.5 Hz, 3H); 13C NMR (75 MHz, DMSO-d6) δ177.8, 167.4, 161.6, 161.2, 142.8, 139.7, 137.2, 136.7, 134.4, 132.7, 130.8, 129.1, 129.3, 127.8, 127.1, 124.1, 123.6, 120.9, 120.4, 120.3, 119.6, 109.7, 92.9, 80.4, 72.6, 57.4, 41.5, 28.8, 28.1, 16.3; MS (ES+) m/z 517.2 (M+1).
