Reaction Steps
Following the procedure as described in EXAMPLE 11.23 and making non-critical variations using isobutyryl chloride to replace trimethylacetic anhydride, and 2-(4′-chloro-2′-oxospiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-1′(2′H)-yl)-N′-hydroxyacetimidamide to replace N′-hydroxy-2-(2′-oxo-6H-spiro[benzofuro[6,5-d][1,3]dioxole-7,3′-indoline]-1′-yl)acetimidamide, 4′-chloro-1′-{[5-(1-methylethyl)-1,2,4-oxadiazol-3-yl]methyl}spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one was obtained (26%) as a colorless solid: mp 165-167° C.; 1H NMR (300 MHz, CDCl3) δ7.19 (dd, J=8.0, 8.0 Hz, 1H), 7.00 (dd, J=8.2, 0.8 Hz, 1H), 6.77 (dd, J=7.8, 0.7 Hz, 1H), 6.46 (s, 1H), 6.32 (s, 1H), 5.85 (ABq, 2H), 5.04 (ABq, 2H), 4.95 (ABq, 2H), 3.17 (sep, J=7.0 Hz, 1H), 1.36 (d, J=7.0 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ185.2, 177.1, 165.3, 156.7, 149.2, 143.0, 142.1, 131.6, 130.1, 128.4, 124.6, 116.5, 107.3, 103.1, 101.5, 93.2, 77.1, 58.8, 36.2, 27.5, 20.1, 20.0; MS (ES+) m/z 440.1 (M+1).
