2-(6-Hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid → 2-(6-Hydroxy-3-oxo-3H-xanthen-9-yl)-benzoic acid 2-propenyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Bromo-1-propene (0.78 mL, 9.0 mmol) was added dropwise under argon to a stirred mixture of fluorescein 16 (3.0 g, 9.0 mmol) and K2CO3 (1.24 g, 9.0 mmol) in dry DMF (40 mL). The resulting mixture was stirred for 4 h at 65° C. The mixture was concentrated, diluted with ethyl acetate, washed with 10% NaHCO3, brine, dried with anhydrous Na2SO4, and evaporated. The residue was purified by column chromatography (ethyl acetate/hexane=2:1) to give 21 as a brown solid (0.70 g, 21%). 1H NMR (CDCl3, 500 MHz) δ 4.42 (d, J=6.0 Hz, 2H, CH2), 5.06 (m, 2H, 2CH), 5.53 (m, 1H, CH), 6.81 (m, 2H), 6.88 (m, 2H), 6.98 (m, 2H), 7.32 (d, J=7.5 Hz, 1H), 7.68 (t, J=7.5 Hz, 1H), 7.74 (t, J=7.5 Hz, 1H), 8.26 (d, J=7.5 Hz, 1H). 13C NMR (CDCl3, 125 MHz) δ 66.26, 103.90, 115.01, 119.49, 122.30, 130.02, 130.51, 130.65, 131.00, 131.38, 132.77, 134.48, 155.89, 158.06, 165.08, 175.84. ESIMS calcd for C23H17O5 [M+H]+ 373.1. Found 373.2.

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