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

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 2,4-dihydroxybenzonitrile (4.33 g, 32.1 mmol) in tetrahydrofuran (50 mL) and 1,2-dichloroethane (400 mL) was added isopropylmagnesium chloride (17.7 mL, 2.0 M solution in tetrahydrofuran, 35.4 mmol) at 0° C. The mixture was stirred at 0° C. for 1 h and at ambient temperature for 2 h, and 1-(4-methoxybenzyl)-1H-indole-2,3-dione (8.58 g, 32.1 mmol) was added to the reaction mixture. The mixture was stirred at reflux for 18 h, cooled to 0° C. and 5% v/v hydrochloric acid was added. The organic layer was separated and 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 2,4-dihydroxy-5-[3-hydroxy-1-(4-methoxybenzyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]benzonitrile (10.30 g, 79%): 1H NMR (300 MHz, DMSO-d6) δ 10.81 (s, 1H), 10.35 (s, 1H), 7.80 (s, 1H), 7.32 (d, J=9.0 Hz, 1H), 7.14-7.08 (m, 1H), 6.88-6.84 (m, 4H), 6.75-6.72 (m, 1H), 6.63 (s, 1H), 6.30 (s, 1H), 4.79 (ABq, 2H), 3.70 (s, 3H); MS (ES+) m/z 384.8 (M−17).

Provenance & Evidence