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

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Reaction Steps

To a stirred suspension of 2,4-dihydroxy-5-[3-hydroxy-1-(4-methoxybenzyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]benzonitrile (10.3 g, 25.5 mmol) and triethylsilane (12.3 mL, 77.0 mmol) in dichloromethane (100 mL) was added trifluoroacetic acid (10.0 mL, 129 mmol). The reaction mixture was stirred at ambient temperature for 18 h and concentrated in vacuo. The residue was triturated in hexanes to afford 2,4-dihydroxy-5-[1-(4-methoxybenzyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]benzonitrile (9.70 g, 98%): mp 162-163° C. (hexanes); 1H NMR (300 MHz, CDCl3) δ 10.84 (s, 1H), 10.47 (s, 1H), 7.39 (s, 1H), 7.28 (d, J=9.0 Hz, 2H), 7.13-7.08 (m, 1H), 6.93-6.78 (m, 5H), 6.43 (s, 1H), 5.72 (s, 1H), 4.92-4.73 (m, 3H), 3.69 (s, 3H); MS (ES+) m/z 386.9 (M+1).

Provenance & Evidence