Water → Ethyl 3-(1'-methyl-2'-oxo-1',2,2',3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3'-indol]-4'-yl)-3-oxopropanoate

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Reaction Steps

To a suspension of sodium hydride (60% w/w dispersion in mineral oil, 0.11 g, 2.8 mmol) in anhydrous tetrahydrofuran (10 mL) at ambient temperature was added diethyl carbonate (0.26 mL, 2.1 mmol) and the mixture was heated at reflux for 5 min. 4′-Acetyl-1′-methyl-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one (0.50 g, 1.4 mmol) was added in one portion and the reaction mixture was heated at reflux for 16 h, allowed to cool to ambient temperature and poured into water (75 mL). The mixture was extracted with dichloromethane (3×50 mL). The combined organic extracts were washed with brine (50 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by column chromatography and eluted with a 0% to 10% gradient of ethyl acetate in dichloromethane, followed by recrystallization from dichloromethane/diethyl ether to afford ethyl 3-(1′-methyl-2′-oxo-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-4′-yl)-3-oxopropanoate (0.235 g, 39%) as a pale yellow solid: 1H NMR (300 MHz, CDCl3) δ 7.50-7.43 (m, 2H), 7.14-7.09 (m, 1H), 6.51 (s, 1H), 6.02 (s, 1H), 4.97-4.78 (m, 2H), 4.20-4.03 (m, 6H), 3.89 (d, J=15.6 Hz, 1H), 3.65 (d, J=15.6 Hz, 1H), 3.29 (s, 3H), 1.16 (t, J=7.1 Hz, 3H); MS (ES+) m/z 445.8 (M+23).

Provenance & Evidence