1'-benzhydryl-6-(benzyloxy)-2H-spiro[benzofuran-3,3'-indolin]-2'-one → 1'-(diphenylmethyl)-6-hydroxyspiro[1-benzofuran-3,3'-indol]-2'(1'H)-one

Participants

Reaction Steps

A suspension of 6-(benzyloxy)-1′-(diphenylmethyl)spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (1.00 g, 2.0 mmol) in methanol/ethyl acetate (15/25 mL) was degassed by bubbling through nitrogen for 1 h before palladium on carbon (5%, 0.42 g, 0.2 mmol) was added. The mixture was stirred under hydrogen at ambient temperature for 16 h. The mixture was filtered through a pad of celite, and the filtrate was concentrated in vacuo. The obtained residue was recrystallized from ethyl acetate and hexane to afford 1′-(diphenylmethyl)-6-hydroxyspiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (0.78 g, 95%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ 7.42-7.25 (m, 10H), 7.16-7.10 (m, 1H), 7.07-6.92 (m, 3H), 6.54-6.48 (m, 1H), 6.44 (d, J=8.2 Hz, 1H), 6.33 (d, J=2.2 Hz, 1H), 6.20 (dd, J=8.2, 2.2 Hz, 1H), 5.65 (s, 1H), 4.99 (d, J=9.0 Hz, 1H), 4.71 (d, J=9.0 Hz, 1H); MS (ES+) m/z 420.1 (M+1).

Provenance & Evidence