Reaction Steps
Following the procedure as described in EXAMPLE 8 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 spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one, and 1-bromopentane to replace (R)-(1,4-dioxan-2-yl)methyl 4-methylbenzenesulfonate, 1′-pentyl-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one was obtained (91%) as a colorless solid: mp 129-130° C. (diethyl ether/hexanes); 1H NMR (300 MHz, CDCl3) δ 7.29 (ddd, J=8.0, 7.7, 1.5 Hz, 1H), 7.16 (d, J=7.5 Hz, 1H), 7.04 (dd, J=7.5, 7.5 Hz, 1H), 6.90 (d, J=7.8 Hz, 1H), 6.49 (s, 1H), 6.21 (s, 1H), 4.88 (d, J=9.0 Hz, 1H), 4.63 (d, J=9.0 Hz, 1H), 4.23-4.17 (m, 2H), 4.14-4.09 (m, 2H), 3.87-3.77 (m, 1H), 3.72-3.62 (m, 1H), 1.77-1.68 (m, 2H), 1.45-1.30 (m, 4H), 0.91 (t, J=6.6 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ177.3, 155.3, 144.6, 142.5, 138.3, 132.7, 128.9, 124.0, 123.2, 121.3, 111.6, 108.7, 99.4, 80.2, 64.6, 64.0, 58.1, 40.4, 29.1, 27.2, 22.4, 14.1; MS (ES+) m/z 366.0 (M+1).
