Reaction Steps
Following the procedure as described in EXAMPLE 12 and making non-critical variations using piperidine 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, 1′-[2-(piperidin-1-ylcarbonyl)benzyl]-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one was obtained (88%) as a colorless solid: mp 168-170° C.; 1H NMR (300 MHz, DMSO-d6) δ7.42-7.10 (m, 6H), 6.99 (dd, J=7.5, 7.5 Hz, 1H), 6.65-6.44 (br, 1H), 6.39 (s, 1H), 4.90-4.64 (m, 4H), 4.54-4.39 (m, 2H), 3.77-3.42 (br, 2H), 3.21-3.07 (m, 2H), 2.94 (t, J=8.2, 1.5 Hz, 1H), 1.66-1.33 (m, 6H); 13C NMR (75 MHz, DMSO-d6) δ177.7, 167.9, 161.6, 161.2, 142.7, 136.4, 132.6, 129.6, 129.1, 128.1, 126.6, 124.1, 123.5, 120.9, 120.3, 109.8, 92.9, 80.5, 72.6, 65.4, 57.4, 47.9, 42.3, 41.4, 28.8, 26.4, 25.7, 24.4, 15.6; MS (ES+) m/z 481.2 (M+1).
