Pyridine → 3-(Cyclopentyloxy)-4-(difluoromethoxy)benzeneacetonitrile

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Reaction Steps

To a solution of (3-cyclopentyloxy-4-difluoromethoxyphenyl)benzaldehyde (3.4 g, 13.4 mmol) in absolute ethanol (33 mL) under an argon atmosphere at room temperature and was added sodium borohydride (1.06 g, 28 mmol). After 20 min, 10% aqueous sodium hydroxide (15 mL) was added, the ethanol was removed in vacuo and the aqueous residue was extracted three times with ether. The organic extract was washed twice with brine, was dried (magnesium sulfate) and evaporated to a pale yellow oil (3.44 g). A solution of this alcohol (1.52 g, 5.89 mmol) and pyridine (0.48 mL, 6 mmol) in alumina-dried chloroform (15 mL) under an argon atmosphere was treated with thionyl chloride (0.52 mL, 7.08 mmol) and the mixture was heated at reflux for 1 h. The solvent was removed, ether was added and the precipitate was removed by filtration. The filtrate was concentrated to a pale yellow oil, which was dissolved in dimethylformamide (10 mL) under an argon atmosphere and treated with sodium cyanide (0.58 g, 11.8 mmol). After stirring at room temperature for 72 h, the mixture was partitioned between 5% aqueous sodium carbonate and ether. The organic extract was washed four times with water, was dried (potassium carbonate) and evaporated. Purification by flash chromatography, eluting with 15-20% ethyl acetate/hexanes, provided a pale yellow solid (3.2 g, 90%): m.p. 39°-41° C.

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