N-methyl-2-pyrrolidone → 4-Chloro-2-hydroxy-9H-fluoren-9-one

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere, to 4-chloro-2-methoxy-9H-fluoren-9-one (92.0 g) were added N-methylpyrrolidone (120 ml) and pyridine hydrochloride (144 g). The reaction mixture was stirred at an oil bath temperature of 200° C. for 3 hr with removing water by a Dean-Stark apparatus. The reaction mixture was cooled to 90° C., water (600 ml) was added dropwise, and the mixture was stirred at room temperature for 2 hr. The precipitated solid was collected by filtration, and washed with water (400 ml). The obtained solid was air-dried for 3 days, a mixed solvent of hexane and ethyl acetate (hexane:ethyl acetate 1:1, 300 ml) was added, and the mixture was stirred at room temperature for 1 hr. The solid was collected by filtration, and washed with a mixed solvent of hexane and ethyl acetate (hexane:ethyl acetate=1:1, 500 ml). The obtained solid was dried under reduced pressure at 50° C. for 3 hr to give the title compound (48.6 g).

Provenance & Evidence