Formaldehyde → 5-fluoro-3-(6-hydroxy-1,3-benzodioxol-5-yl)-3-(hydroxymethyl)-1-{[5-(trifluoromethyl)-2-furyl]methyl}-1,3-dihydro-2H-indol-2-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-fluoro-3-(6-hydroxy-1,3-benzodioxol-5-yl)-1-{[5-(trifluoromethyl)-2-furyl]methyl}-1,3-dihydro-2H-indol-2-one (3.64 g, 8.41 mmol), para-formaldehyde (2.52 g, 84.1 mmol) and lithium hydroxide monohydrate (1.06 g, 25.2 mmol) in tetrahydrofuran (84.0 mL) and water (10.0 mL) was stirred at 0° C. for 4 h. After the solvent was removed in vacuo, the residue was dissolved in ethyl acetate (100 mL), washed with 10% aqueous HCl (3×25.0 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness. The residue was subjected to column chromatography eluting with ethyl acetate/hexanes (50%) to give the title compound (0.65 g, 59%) as a colorless solid: 1H NMR (300 MHz, DMSO-d6) δ 9.11 (s, 1H), 7.12 (d, 1H), 6.99-6.87 (m, 3H), 6.80 (dd, 1H), 6.48 (d, 1H), 6.23 (s, 1H), 5.89 (d, 2H), 5.09 (br, 1H), 4.97 (ABq, 2H), 4.01 (ABq, 2H); 13C NMR (75 MHz, DMSO-d6) δ 176.1, 160.5; MS (ES+) m/z 466.2 (M+1), 448.2 (M−17).

Provenance & Evidence