Following the procedure as described in EXAMPLE 12 and making non-critical variations using aniline 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]-N-phenylbenzamide was obtained (90%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ8.34 (s, 1H), 7.83 (d, J=7.8 Hz, 2H), 7.60 (d, J=8.3 Hz, 2H), 7.39-7.23 (m, 4H), 7.23-6.97 (m, 4H), 6.72 (d, J=7.7 Hz, 1H), 6.44 (s, 1H), 6.38 (s, 1H), 4.92 (ABq, 2H), 4.77 (ABq, 2H), 4.48 (t, J=8.5 Hz, 2H), 2.89 (t, J=8.5 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ178.1, 165.2, 161.8, 161.3, 141.6, 139.4, 137.9, 134.6, 132.4, 128.8, 128.7, 127.8, 127.4, 124.4, 123.9, 123.7, 120.2, 119.9, 119.7, 118.7, 109.1, 93.2, 80.4, 72.3, 57.7, 43.7, 28.8; MS (ES+) m/z 489.1 (M+1).
