Reaction Steps
Following the procedure as described in EXAMPLE 4 and making non-critical variations using 2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one to replace 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2″(1′H)-one, and 1-bromo-3-methylbutane to replace 2-(bromomethyl)tetrahydro-2H-pyran, 1′-(3-methylbutyl)-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one was obtained (64%) as a colorless solid: mp 134-137° C. (hexanes); 1H NMR (300 MHz, CDCl3) δ7.30 (ddd, J=7.7, 7.7, 1.3 Hz, 1H), 7.15 (dd, J=7.2, 0.9 Hz, 1H), 7.03 (ddd, J=7.4, 7.4, 0.7 Hz, 1H), 6.89 (d, J=7.8 Hz, 1H), 6.49 (s, 1H), 6.20 (s, 1H), 4.88 (d, J=9.0 Hz, 1H), 4.62 (d, J=9.0 Hz, 1H), 4.21-4.16 (m, 2H), 4.14-4.09 (m, 2H), 3.89-3.80 (m, 1H), 3.73-3.63 (m, 1H), 1.75-1.59 (m, 3H), 1.00 (d, J=6.3 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ177.3, 155.4, 144.6, 142.5, 138.3, 132.8, 128.9, 124.0, 123.2, 121.3, 111.6, 108.6, 99.4, 80.2, 64.6, 64.0, 58.1, 38.9, 36.3, 26.2, 22.7, 22.6; MS (ES+) m/z 366.3 (M+1); Anal. Calcd for C22H23NO4: C, 72.31; H, 6.34; N, 3.83. Found: C, 72.21; H, 6.31; N, 3.55.
