Trifluoroacetic acid → 1-(diphenylmethyl)-3-(2-hydroxy-4-methoxy-5-methylphenyl)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

To a stirred mixture of 1-(diphenylmethyl)-3-hydroxy-3-(2-hydroxy-4-methoxy-5-methylphenyl)-1,3-dihydro-2H-indol-2-one (15.4 g, 34.1 mmol) and triethylsilane (15 mL) was added trifluoroacetic acid (15 mL) at 0° C. The solution was stirred at ambient temperature for 16 h and concentrated in vacuo to dryness. The residue was recrystallized from diethyl ether (25 mL) in a Branson ultrasonic bench top water bath to afford 1-(diphenylmethyl)-3-(2-hydroxy-4-methoxy-5-methylphenyl)-1,3-dihydro-2H-indol-2-one (11.0 g, 74%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ7.42-7.16 (m, 12H), 7.11-7.01 (m, 2H), 6.94 (s, 1H), 6.61 (s, 1H), 6.57-6.49 (m, 1H), 6.45 (s, 1H), 5.08 (s, 1H), 3.63 (s, 3H), 2.03 (s, 3H); MS (ES+) m/z 436.3 (M+1).

Provenance & Evidence