Trifluoroacetic acid → 7-Fluoro-1,3-dihydro-3-hydroxy-3-phenyl-2H-indol-2-one

Participants

Reaction Steps

To a stirring solution of 7-fluoroindoline-2,3-dione (12.22 g, 74 mmol) in THF (40 mL) at 0° C. was added phenylmagnesium bromide (148 mL, 148 mmol) dropwise. The reaction mixture was allowed to stir at room temperature after addition was completed. The reaction mixture was judged complete by HPLC after 15 min. The reaction mixture was quenched with saturated NH4Cl and extracted with EtOAc. The combined extracts were washed with brine, dried (Na2SO4), filtered and concentrated. The residue was purified by silica gel chromatography (EtOAc/hexane) to afford Intermediate A11A (18.84 g, 88%) as yellow solid: HPLC: RT=1.810 min (H2O/MeOH with TFA, CHROMOLITH® SpeedROD, 4.6×50 mm, gradient=4 min, wavelength=220 nm); MS(ES): m/z=226 [M+H+—H2O]; 1H NMR (400 MHz, DMSO-d6) δ 10.92 (s, 1H), 7.37-7.25 (m, 5H), 7.19 (ddd, J=10.4, 8.1, 1.3 Hz, 1H), 7.04-6.92 (m, 2H).

Provenance & Evidence