Water → Ethyl 4-[(9R)-4-chloro-9-hydroxy-9-(trifluoromethyl)-9H-fluoren-2-yloxy]butyrate

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Reaction Steps

(9R)-4-Chloro-9-(trifluoromethyl)-9H-fluorene-2,9-diol (200 mg) obtained in step 10 of example 1 was dissolved in N,N-dimethylformamide (2 ml), potassium carbonate (185 mg) and ethyl 4-bromobutyrate (105 μl) were added, and the mixture was stirred at room temperature for 7 hr. To the reaction mixture was added water, and the mixture was extracted twice with ethyl acetate. The obtained organic layer was washed successively with water (twice) and saturated brine. The obtained organic layer was dried over anhydrous magnesium sulfate, the insoluble material was filtered off, and the solvent in the filtrate was evaporated. The obtained residue was purified by silica gel column chromatography (a mixture of hexane and ethyl acetate was used as an elution solvent, first eluted with a mixture at a mixing ratio 5:1 (hexane:ethyl acetate), then successively with a mixture at a mixing ratio 3:1, and further with a mixture at a mixing ratio 2:1) to give the title compound (197 mg).

Provenance & Evidence