Phosphorus pentachloride → 5-Acetylamino-7,8-difluoro-1-tetralone

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Reaction Steps

The compound obtained in (4) above (9.07 gm) was dissolved into 450 ml of dichloromethane. To the mixture was added 7.71 gm of phosphorous pentachloride while stirring at room temperature. After stirring for a further 1 hour, the reaction mixture was concentrated and dichloromethane was added to the residue. Dichloromethane was evaporated again and 500 ml of 1,2-dichloroethane and 9.88 gm of anhydrous aluminum chloride were added to the residue. The mixture was stirred for 1 hour at 70° C. and gently heated under reflux for 15 hours. The reaction product was poured into ice-cold water, extracted with chloroform, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated and the residue was subjected to silica gel column chromatography using chloroform-methanol (50:1) as an eluant to obtain fractions containing the target compound. The fractions were concentrated to obtain 2.31 gm of the title compound.

Provenance & Evidence