Reaction Steps
A mixture of 4-bromo-3-(6-hydroxy-2,3-dihydro-1-benzofuran-5-yl)-3-(hydroxymethyl)-1-(pyridin-2-ylmethyl)-1,3-dihydro-2H-indol-2-one (1.81 g, 3.88 mmol), triphenylphosphine (2.04 g, 7.77 mmol) and diisopropyl azodicarboxylate (1.57 g, 7.77 mmol) in anhydrous dioxane (60 mL) was heated at reflux for 16 h. After cooling down to ambient temperature, the solvent was removed in vacuo. The gummy residue was diluted with ethyl acetate (50.0 mL), washed with water (3×25.0 mL), brine (3×25.0 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness. The residue was subjected to column chromatography eluting with ethyl acetate/hexane (80%) to give the title compound (0.64 g, 37%) as colorless solid: mp >200° C.; 1H NMR (300 MHz, DMSO-d6) δ 8.47 (d, 1H), 7.77 (dt, 1H), 7.37 (d, 1H), 7.27 (dt, 1H), 7.19-7.13 (m, 2H), 6.94 (dd, 1H), 6.61 (s, 1H), 6.33 (s, 1H), 5.08 (d, 1H), 5.03 (d, 1H), 4.93 (d, 1H), 4.74 (d, 1H), 4.48 (t, J=8.6 Hz, 2H), 2.96 (t, 2H); 13C NMR (75 MHz, DMSO-d6) δ 177.4, 162.2, 161.8, 155.3, 149.8, 145.3, 137.6, 131.0, 130.5, 126.8, 123.3, 122.2, 119.9, 119.5, 119.0, 118.1, 109.3, 92.4, 77.5, 72.5, 58.8, 45.3, 28.8; MS (ES+) m/z 451.3 (M+1).
