反应详情

To a solution of phenyl 1′-methyl-2′-oxo-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indole]-4′-carboxylate (2.00 g, 4.65 mmol) in tetrahydrofuran (50 mL) and water (10 mL) was added lithium hydroxide monohydrate (1.00 g, 23.8 mmol) at ambient temperature. The reaction mixture was stirred at ambient temperature for 18 h and concentrated in vacuo. The residue was neutralized to pH 4-5 with 10% w/v hydrochloric acid. The resultant precipitate was filtered and washed with diethyl ether to afford 1′-methyl-2′-oxo-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indole]-4′-carboxylic acid (1.40 g, 85%): mp 297-299° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.54-7.43 (m, 3H), 7.32-7.28 (m, 1H), 6.31 (s, 1H), 6.03 (s, 1H), 4.77 (ABq, 2H), 4.12-4.02 (m, 4H), 3.15 (s, 3H); MS (ES+) m/z 376.0 (M+23).

1. concentrationconcentrated in vacuo
2. filtrationThe resultant precipitate was filtered
3. washwashed with diethyl ether