Hydrochloric Acid → Methyl 5-[3-fluoro-4-(2,2,2-trifluoroethyl)phenyl]piperidine-3-carboxylate

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Reaction Steps

A solution of 7.75 g (17.1 mmol, purity 69%) of the compound from Example 75A in methanol (107 ml) was admixed with 1.50 g of platinum(IV) oxide and concentrated hydrochloric acid solution (13.4 ml). This was followed by hydrogenation under a hydrogen atmosphere at 3.5 bar overnight, then addition of another 800 mg of platinum(IV) oxide and again by hydrogenation under a hydrogen atmosphere at 3.5 bar overnight. Addition of another 1.00 g of platinum(IV) oxide was followed by hydrogenation under a hydrogen atmosphere at 3.5 bar overnight. The reaction solution was filtered through Celite, the filter residue was washed with methanol and the combined filtrates were concentrated under reduced pressure. The residue was taken up in water, then adjusted to pH=9 with a 1 N aqueous sodium hydroxide solution and subsequently extracted with ethyl acetate. The organic phase was dried over sodium sulphate, filtered and concentrated under reduced pressure. Yield: 6.01 g (86% of theory, purity 78%)

Provenance & Evidence