Hydrochloric Acid → 2-fluoro-4-hydroxy-5-[3-hydroxy-1-(4-methoxybenzyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]benzonitrile

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Reaction Conditions

Reaction Steps

To a stirred solution of 2-fluoro-4-hydroxybenzonitrile (8.00 g, 58.3 mmol) in 1,2-dichloroethane (500 mL) and tetrahydrofuran (50 mL) was added isopropylmagnesium chloride (29.2 mL, 2.0 M solution in tetrahydrofuran, 58.4 mmol) at 0° C. The mixture was stirred at 0° C. for 1 h and at ambient temperature for 2 h. 1-(4-methoxybenzyl)-1H-indole-2,3-dione (15.0 g, 56.1 mmol) was added and the reaction mixture was stirred at reflux for 156 h. The mixture was cooled to 0° C. and 10% w/v hydrochloric acid was added. The phases were separated and the aqueous layer was extracted with dichloromethane (100 mL). The combined organic extracts were washed with water and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo. The residue was subjected to column chromatography and eluted with ethyl acetate/hexanes (1/1) to afford 2-fluoro-4-hydroxy-5-[3-hydroxy-1-(4-methoxybenzyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]benzonitrile (12.30 g, 54%): 1H NMR (300 MHz, DMSO-d6) δ 8.05 (d, J=9.0 Hz, 1H), 7.34-7.32 (m, 2H), 7.17-7.11 (m, 1H), 6.91-6.76 (m, 7H), 4.78 (ABq, 2H), 3.72 (s, 3H); MS (ES+) m/z 404.9 (M+1).

Provenance & Evidence