Dimethyl Sulfoxide → 7,8-difluoroquinolin-3-ol

Participants

Reaction Conditions

Reaction Steps

In a 3 L eggplant-shaped flask containing a stir bar, 7,8-difluoro-3-iodoquinoline (227.2 g, 0.78 mol), dimethylsulfoxide (600 mL), and water (600 mL) were introduced and sodium hydroxide (131.5 g, 2.34 mol), CuI (14.8 g, 0.078 mol), and 1,10-phenanthroline (28.1 g, 0.156 mol) were added. The mixture was further heated to 100° C. in an oil bath and was stirred for 24 hours. After cooling, the organic layer was removed by adding ethyl acetate and water. The thus obtained aqueous layer was neutralized with concentrated hydrochloric acid, and then the precipitated crystals were filtered and dried. On the other hand, after the filtrate was extracted with ethyl acetate, dried with magnesium sulfate, filtered and concentrated, the crude product obtained was purified by silica gel column chromatography (normal hexane:ethyl acetate) to obtain 133.7 g (95%) of 7,8-difluoro-3-hydroxyquinoline as a hazel solid combined with the previously obtained crystals.

Provenance & Evidence