Sulfuric Acid → 7-Phenylnaphthalene-2-carboxylic acid

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Reaction Steps

In methanol (35 ml) was dissolved 7-phenyl-3,4-dihydronaphthalene-2-carboxylic acid (1.50 g), and to the mixture was added concentrated sulfuric acid (0.1 ml), and then the mixture was refluxed for 9 hours. The reaction mixture was cooled to room temperature, and to the mixture was added 5% sodium hydrogen carbonate solution, and then the mixture was extracted with ethyl acetate. The organic layer was washed with saturated sodium chloride solution, dried with anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was dissolved in ethyl acetate (100 ml), and to the mixture was added activated manganese dioxide (9 g). The mixture was refluxed for 48 hours and then cooled to room temperature. The manganese dioxide was filtered off, and the filtrate was concentrated. The residue was dissolved in methanol (15 ml), and to the mixture was added 1N sodium hydroxide (10 ml). The mixture was refluxed for 4 hours and then cooled to room temperature. The mixture was acidified with dilute hydrochloric acid, and extracted with ethyl acetate. The organic layer was washed with saturated sodium chloride solution, dried with anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was recrystallized from ethyl acetate-diisopropylether to give 7-phenylnaphthalene-2-carboxylic acid (783 mg) as colorless crystals.

Provenance & Evidence