Reaction Steps
Following the procedure as described in EXAMPLE 4 and making non-critical variations using 2-methylspiro[furo[2,3-f][1,3]benzothiazole-7,3′-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 4-(bromomethyl)tetrahydropyran to replace 2-(bromomethyl)tetrahydro-2H-pyran, 2-methyl-1′-(tetrahydro-2H-pyran-4-ylmethyl)spiro[furo[2,3-f][1,3]benzothiazole-7,3′-indol]-2′(1′H)-one was obtained (44%) as a colorless solid: mp 186-187° C. (hexanes/ethyl acetate); 1H NMR (300 MHz, CDCl3) δ7.66-7.60 (m, 1H), 7.34-7.27 (m, 1H), 7.13-7.07 (m, 1H), 7.06-6.91 (m, 3H), 5.04-4.97 (m, 1H), 4.78-4.72 (m, 1H), 4.07-3.93 (m, 3H), 3.52-3.35 (m, 3H), 2.52 (s, 3H), 2.32-2.15 (m, 1H), 2.07-1.95 (m, 1H), 1.91-1.80 (m, 1H), 1.57-1.42 (m, 2H); 13C NMR (75 MHz, CDCl3) δ177.4, 169.3, 160.6, 149.2, 143.1, 132.7, 129.1, 128.7, 123.7, 123.0, 122.3, 119.9, 108.7, 108.5, 81.5, 67.9, 62.4, 58.1, 46.6, 34.3, 30.9, 20.2, 14.6; MS (ES+) m/z 407.0 (M+1).
