Reaction Steps
Following the procedure as described in EXAMPLE 9.70 and making non-critical variations using 4′,6′-dimethoxy-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one to replace (8S)-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one, 4′,6′-dimethoxy-1′-[2-(2-methoxyethoxy)ethyl]-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one was obtained (80%) as a colorless solid: mp 158-160° C.; 1H NMR (300 MHz, DMSO-d6) δ6.43 (s, 1H), 6.33 (d, J=4.2 Hz, 1H), 6.20 (s, 1H), 6.06 (d, J=4.2 Hz, 1H), 4.70-4.46 (m, 2H), 4.19-3.99 (m, 4H), 3.79-3.72 (m, 2H), 3.65-3.52 (m, 4H), 3.52-3.42 (m, 2H), 3.38-3.24 (m, 6H), 3.18-3.11 (m, 3H); 13C NMR (75 MHz, CDCl3) δ178.8, 162.0, 156.7, 155.6, 155.5, 144.7, 144.1, 137.6, 120.4, 110.9, 109.2, 98.8, 92.9, 89.2, 71.0, 70.4, 68.3, 64.4, 63.9, 59.0, 56.9, 55.6, 55.5, 40.3; MS (ES+) m/z 458.1 (M+1).
