6-Methoxy-alpha-tetralone → 1-Naphthalenecarbonitrile, 3,4-dihydro-6-methoxy-

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Reaction Steps

Trimethylsilylcyanide (50.0 g, 510 mmol) was added to a suspension of 75.0 g (430 mmol) of 6-methoxy-α-tetralone (commercially available from Aldrich Chemical Company) in 75 mL of anhydrous tetrahydrofuran (THF) at ambient temperature. Lithium cyanide (100 mL of a 0.5M solution in N,N-dimethylformamide (DMF) was added to the resultant mixture in one portion. The reaction mixture was stirred at ambient temperature for 1.5 h and then the THF was removed under reduced pressure. The concentrate was partitioned between diethyl ether and water (5:1 v/v). The aqueous layer was extracted with diethyl ether and the combined organic extract was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was dissolved in 400 mL of anhydrous toluene, containing 15 g of p-toluenesulfonic acid, previously refluxed in order to remove residual water by azeotropic distillation. The mixture was heated at reflux (with a Dean Stark trap) for 1 h. The resultant solution was cooled to ambient temperature and washed with cold 1N aqueous sodium hydroxide solution. The organic layer was separated, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The residue was purified on silica gel eluted with 10% ethyl acetate in hexane to afford 48.09 g (60% yield) of the title compound. The physical properties of the product were identical to the properties reported for this compound by F. Z. Basha, et al. in J. Organic Chemistry, 50: 4160-2 (1985).

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