Trifluoroacetic acid → 3-[5-(benzyloxy)-2-hydroxyphenyl]-1-[(5-chlorothiophen-2-yl)methyl]-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

To a solution of 3-[5-(benzyloxy)-2-hydroxyphenyl]-1-[(5-chloro-2-thienyl)methyl]-3-hydroxy-1,3-dihydro-2H-indol-2-one (4.90 g, 10.3 mmol) in dichloromethane (100.0 mL) were added trifluoroacetic acid (12.9 g, 113.2 mmol) and triethylsilane (13.2 g, 113.2 mmol). The reaction mixture was stirred at ambient temperature for 4 h, then concentrated in vacuo to dryness. The gummy residue was diluted with ethyl acetate (100.0 mL), washed with water (3×100.0 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness. The residue was triturated with diethyl ether, filtered and dried to afford 3-[5-(benzyloxy)-2-hydroxyphenyl]-1-[(5-chlorothiophen-2-yl)methyl]-1,3-dihydro-2H-indol-2-one (2.90 g, 61%) as a colourless solid: mp 173-175° C.; 1H NMR (300 MHz, CDCl3) δ9.11 (s, 1H), 7.3-7.27 (m, 5H), 7.18 (dd, J=7.5, 7.5 Hz, 1H), 7.09 (d, J=3.8 Hz, 1H), 7.06 (dd, J=7.9 Hz, 1H), 6.97-6.86 (m, 3H), 6.79-6.68 (m, 3H), 5.04 (ABq, 2H), 4.91 (s, 2H), 4.84 (s, 1H); 13C NMR (75 MHz, CDCl3) δ175.9, 151.5, 149.7, 142.8, 138.8, 137.8, 130.2, 128.8, 128.2, 128.1, 128.1, 128.0, 127.4, 126.8, 125.2, 124.2, 122.7, 117.6, 117.6, 116.3, 114.9, 109.1, 70.2, 48.1, 38.6; MS (ES+) m/z 464.3 (M+1), 462.3 (M+1).

Provenance & Evidence