Hydrochloric Acid → (1R,2S,4R)-5,5-Difluorobicyclo[2.2.1]heptan-2-amine hydrochloride

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Reaction Conditions

Reaction Steps

To a suspension of 2-((1R,2S,4R)-5,5-difluorobicyclo[2.2.1]-heptan-2-yl)isoindoline-1,3-dione (0.58 g, 2.09 mmol) in ethanol (anhydrous, 30 mL) was added hydrazine (0.10 mL, 3.14 mmol). After refluxing this mixture under nitrogen for 5 h, it was cooled in an ice bath, and hydrochloric acid (37%, 0.50 mL) was added. After stirring at 60° C. for 1.5 h, the mixture was cooled to ambient temperature. After the white solid was removed by filtration, the filter cake was washed with methanol, and the filtrate was conc. in vacuo. The resulting residue was diluted in ˜50 mL of water, filtered, and the filtrate was washed with diethyl ether (30 mL×3). The filtrate was then treated with sodium carbonate monohydrate to saturation, and the aqueous layer was extracted with diethyl ether (50 mL×3). These organic layers were combined, dried over potassium carbonate (solid), and filtered. The solution was treated with hydrochloric acid (1M aqueous, 4 mL), stirred for 5 min, and then concentrated in vacuo to give the title compound as a white solid.

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