6-(Pyridin-3-YL)hexanenitrile → 3-Pyridinehexanamine

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Reaction Steps

A solution of 52.15 g of 3-pyridinehexanenitrile in 600 ml of methanol and 13 ml of triethylamine was hydrogenated over 13 g of Raney cobalt at an initial hydrogen pressure of 1000 psi and 100° C. The cooled mixture was filtered and concentrated. The residue was distilled to give 46.5 g (87%) of 3-pyridinehexanamine, bp 102°-107° C./0.2 mm. This material was purified through its phthalimide which was formed by reaction with 39.53 g of phthalic anhydride in 300 ml of glacial acetic acid at reflux overnight. The residue obtained after evaporation of the solvent was dissolved in 300 ml of ethyl acetate, washed with dilute sodium hydroxide and sodium bicarbonate, dried over potassium carbonate and concentrated. The residue was crystallized from ethyl acetate-hexane to give 62.87 g (77%) of 2-[6-(3-pyridinyl)hexyl]-1H-isoindole-1,3(2H)-dione, mp 89°-92° C. A solution of this material in 880 ml of ethanol and 33 ml of hydrazine hydrate was heated to reflux for 3 hours. The cooled mixture was filtered and concentrated. The residue was taken up in 500 ml of dichloromethane and was washed with 10% sodium hydroxide and dried over potassium carbonate. The residue obtained after concentration was distilled to give 31.6 g (60% based on starting nitrile) of 3-pyridinehexanamine, bp 140°-150° C./0.3 mm which gave a single peak on gas chromatography.

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