反应详情

A suspension of 6-(benzyloxy)-1′-(diphenylmethyl)spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (0.60 g, 1.2 mmol) in methanol (20 mL) was degassed by bubbling through nitrogen for 1 h before palladium hydroxide on carbon (20%, 0.08 g, 0.12 mmol) was added. The mixture was stirred under 120 psi of hydrogen at 60° C. for 16 h. The mixture was filtered through a pad of celite, and the filtrate was concentrated in vacuo. The obtained residue was recrystallized with ethyl acetate and hexane to afford 6-hydroxy-2H-spiro[benzofuran-3,3′-indolin]-2′-one (0.25 g, 83%) as a colorless solid: 1H NMR (300 MHz, DMSO-d6) δ 10.86-9.35 (br, 2H), 7.19 (td, J=7.6, 1.2 Hz, 1H), 7.03 (d, J=7.3 Hz, 1H), 6.96-6.84 (m, 2H), 6.42 (d, J=8.2 Hz, 1H), 6.29 (d, J=2.1 Hz, 1H), 6.17 (dd, J=8.2, 2.1 Hz, 1H), 4.72 (d, J=9.2 Hz, 1H), 4.59 (d, J=9.2 Hz, 1H); MS (ES+) m/z 254.1 (M+1).

1. customwas degassed
2. additionwas added
3. filtrationThe mixture was filtered through a pad of celite
4. concentrationthe filtrate was concentrated in vacuo
5. customThe obtained residue was recrystallized with ethyl acetate and hexane