Reaction Steps
Following the procedure as described in EXAMPLE 9 and making non-critical variations using 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one to replace 3-methylspiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-2′(1′H)-one, and 2-(bromomethyl)-7-fluorobenzofuran to replace 2-(bromomethyl)-5-(trifluoromethyl)furan, 1′-[(7-fluoro-1-benzofuran-2-yl)methyl]-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one was obtained (83%) as a colorless solid: mp 192-193° C.; 1H NMR (300 MHz, CDCl3) δ7.31-7.24 (m, 2H), 7.22-6.96 (m, 5H), 6.77-6.74 (m, 1H), 6.56 (s, 1H), 6.43 (s, 1H), 5.31-5.23 (m, 1H), 5.03-4.95 (m, 2H), 4.75-4.68 (m, 1H), 4.59-4.49 (m, 2H), 3.10-2.91 (m, 2H); 13C NMR (75 MHz, CDCl3) δ177.6, 161.8, 161.2, 152.8, 147.8 (d, JC-F=249.7 Hz), 141.9 (d, JC-F=11.3 Hz), 141.4, 132.7, 131.6 (d, JC-F=3.2 Hz), 128.8, 123.9, 123.7, 123.6, 120.1 (d, JC-F=5.2 Hz), 119.0, 116.6 (d, JC-F=3.9 Hz), 110.8 (d, JC-F=16.1 Hz), 109.0, 105.6 (d, JC-F=2.1 Hz), 93.2, 80.4, 72.4, 57.7, 37.5, 29.0; MS (ES+) m/z 428.3 (M+1).
