Methanol → HCID 59352422, compound

Participants

Reaction Steps

A solution of methyl 5-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]furan-2-carboxylate (5.5 g, 13.0 mmol) and sodium hydroxide (1.04 g, 26.0 mmol) in water 100 ml) and methanol (40 mL) was stirred at 65° C. for 16 h. The solvent methanol was evaporated under reduced pressure, and the residue was cooled in ice-bath and acidified with 10% hydrochloric acid to pH 1-2. The solid precipitate was filtered off, and recrystallized from ethanol (100 mL) to afford 5-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]furan-2-carboxylic acid (5.10 g, 92%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ7.36-6.92 (m, 5H), 6.51 (s, 1H), 6.44 (d, J=3.5 Hz, 1H), 6.40 (s, 1H), 5.02 (ABq, 2H), 4.81 (ABq, 2H), 4.51 (t, J=8.6 Hz, 2H), 3.04-2.91 (m, 2H); 13C NMR (75 MHz, CDCl3) δ177.2, 161.6, 160.9, 159.6, 153.7, 145.0, 142.1, 132.7, 129.1, 124.0, 123.7, 121.0, 120.4, 119.6, 119.1, 111.1, 109.7, 92.9, 80.0, 72.6, 57.4, 37.3, 28.8; MS (ES+) m/z 403.8 (M+1).

Provenance & Evidence