Hydrochloric Acid → 7-Phenyl-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

To 7-phenyl-3,4-dihydronaphthalene-2-carboxylic acid (1.00 g) dissolved in methanol (25 ml) was added a concentrated sulfuric acid (0.1 ml), and the resulting mixture was heated at reflux for 48 hours. After cooling to room temperature, the reaction mixture was mixed with a 5% aqueous solution of sodium hydrogen carbonate and was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated solution of sodium chloride, was dried with anhydrous sodium sulfate and was then evaporated under reduced pressure to remove the solvent. To the resulting residue dissolved in ethanol (50 ml) was added dried 10% palladium on charcoal (0.05 g), and the resulting mixture was stirred at an ordinary temperature and under an atmospheric pressure for 48 hours. The palladium on charcoal was removed by a filtration operation, the filtrate was concentrated and the residue was then subjected to purification using column chromatography (ethyl acetate/hexane=1/2) to obtain an oily material. To this material dissolved in methanol (15 ml) was added a 1 N aqueous solution of sodium hydroxide (10 ml), and the resulting mixture was heated at reflux for 3 hours. After cooling to room temperature, the reaction mixture was acidified by the addition of a diluted hydrochloric acid and was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated solution of sodium chloride and was dried with anhydrous magnesium sulfate, and then the solvent was evaporated under reduced pressure. The resulting residue was recrystallized from ethyl acetate/hexane to obtain 7-phenyl-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid (677 mg) as colorless crystals.

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