[F:1][C:2]1[C:11]([O:12][CH3:13])=[CH:10][CH:9]=[C:8]2[C:3]=1[C:4]([CH2:15][OH:16])=[C:5]([OH:14])[CH:6]=[N:7]2.C(OCC)(=O)C.CCCCCC>CC(C)=O.[O-2].[O-2].[Mn+4]>[F:1][C:2]1[C:11]([O:12][CH3:13])=[CH:10][CH:9]=[C:8]2[C:3]=1[C:4]([CH:15]=[O:16])=[C:5]([OH:14])[CH:6]=[N:7]2Manganese dioxide (299 mg, 4.3 mmol, 10.0 eq) is added at room temperature to a stirred solution of 5-fluoro-4-hydroxymethyl-6-methoxy-quinolin-3-ol (120 mg, 0.43 mmol, 1.0 eq) in acetone (12 mL) and the resulting mixture is stirred at 35° C. for 17 hours. The solid is filtered off, washed with acetone (3×10 mL) and the filtrate is concentrated to give a residue that is purified by column chromatography (silica gel, eluent: ethyl acetate:hexane, 1:3, v/v) to afford 5-fluoro-3-hydroxy-6-methoxy-quinoline-4-carbaldehyde as a yellow solid (40 mg, 42% yield).
読み込み中…
