Phosphorus oxybromide → HCID 86617065, compound

Participants

Reaction Steps

A mixture of 6-(4-fluoro-phenoxy)-1,4-dihydroxy-isoquinoline-3-carboxylic acid butyl ester (7.43 g, 20 mmol, prepared according to US 2004/0254215 A1 or scheme), POBr3 (17.38 g, 60 mmol), and anhydrous acetonitrile (140 mL) was refluxed with stirring for 60 minutes before it was concentrated in vacuo. To the residue was added ethyl acetate (400 mL), NaHCO3 (60 g), and then water in small portions (400 mL) with stirring. After stirring for 30 min at room temperature the mixture was filtered through a pad of celite. The organic phase of the filtrate was separated, and dried over MgSO4. Then silica gel was added and the mixture was concentrated in vacuo. The residue was added on top of a short column filled with silica gel. Elution using CH2Cl2 as the solvent gave the title compound as an off-white solid (930 mg); 1H NMR (CDCl3, 200 MHz): δ=11.76 (s, 1H), 8.22 (d, J=9.4 Hz, 1H), 7.61 (d, J=2.3 Hz, 1H), 7.50 (dd, J=9.0, 2.3 Hz, 1H), 7.10 to 7.13 (m, 4H), 4.46 (t, J=7.0 Hz, 2H), 1.85 (m, 2H), 1.45 (m, 2H), 0.99 (t, J=7.4 Hz, 3H).

Provenance & Evidence