Hydrochloric Acid → 2,8-Diacetylamino-5,6-difluoro-1-tetralone

Participants

Reaction Conditions

Reaction Steps

To a mixed solution of 15 ml of a THF solution and 1.5 ml of tert-butanol containing 309 mg of potassium-butoxide was added slowly in a nitrogen stream at 0° C. 300 mg of the compound prepared in (7) above dissolved in 7.5 ml of THF. After stirring for 10 minutes at the same temperature, 0.22 ml of n-butyl nitrite was dropwise added to the mixture, followed by further stirring for 1.5 hours, during which the temperature was slowly raised to 20° C. The reaction mixture was adjusted to pH 1 with the addition of 1N hydrochloric acid, extracted with chloroform, washed with saturated brine, and dried over anhydrous sodium sulfate. To the residue obtained by evaporating the solvent was added a mixture of 15 ml of acetic acid and 15 ml of acetic anhydride, and was added about 1 gm of zinc powder, followed by stirring at 20° C. for 18 hours. Insoluble substances were removed by filtration, the solvent was evaporated, and the residue was extracted with chloroform. The extract was washed with saturated brine and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was subjected to silica gel column chromatography using a chloroform-methanol (97:3) mixed solvent as an eluant to obtain fractions containing the target compound. The fractions were concentrated to produce 311 mg of the title compound.

Provenance & Evidence