[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1[OH:9].S(=O)(=O)(O)O.O[CH2:16][CH:17]([CH2:19]O)O>[N+](C1C=CC=CC=1)([O-])=O>[F:8][C:4]1[C:3]([OH:9])=[C:2]2[C:7]([CH:16]=[CH:17][CH:19]=[N:1]2)=[CH:6][CH:5]=1To a solution of 2-amino-6-fluorophenol (4.0 g, 31.6 mmol) and nitrobenzene (20 mL) in a sealable reaction vessel was added in portions sulfuric acid (4.0 mL). Glycerol (12.0 g, 126 mmol) was added in one portion, and the solution turned to dark brown. The vessel was flushed with nitrogen, sealed and heated to 140° C. for 6 h. The reaction mixture was cooled to rt, diluted with 30 mL ice/water mixture, and washed 3 times with methyl t-butyl ether (removes most of the nitrobenzene). The aqueous phase was neutralized to pH=6-7 by slow addition of 6N NaOH. The resulting black precipitate was collected and the water solution was extracted with ethyl acetate 3 times. The organic extracts were combined with the black precipitate, concentrated in vacuo, and purified on silica gel column with 0-10% MeOH/DCM to give 2.67 g (51.7%) of 7-fluoro-8-quinolinol as an off-white solid.
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