Trifluoroacetic acid → ethyl [4-bromo-3-(4,5-difluoro-2-hydroxyphenyl)-2-oxo-2,3-dihydro-1H-indol-1-yl]acetate

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl [4-bromo-3-(4,5-difluoro-2-hydroxyphenyl)-3-hydroxy-2-oxo-2,3-dihydro-1H-indol-1-yl]acetate (0.90 g, 2.00 mmol), triethylsilane (2.00 mL, 12.2 mmol) and trifluoroacetic acid (0.94 mL, 12.2 mmol) was heated at 90° C. for two days. After cooling down to ambient temperature, the mixture was diluted with ethyl acetate (200 mL), washed with water, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness. The residue was subjected to column chromatography (ethyl acetate/hexanes, 1/3) to give the title compound (0.37 g, 43%): 1H NMR (300 MHz, CDCl3) δ 7.35-7.22 (m, 3H), 6.82-6.71 (m, 2H), 6.52 (t, 1H), 5.10 (s, 1H), 4.45 (s, 2H), 4.21 (q, 2H), 1.23 (t, 3H); MS (ES+) m/z 426.4 (M+1), 428.4 (M+1).

Provenance & Evidence