Hydrochloric Acid → tert-Butyl 4-(5-nitropyridine-2-ylamino)piperidine-1-carboxylate

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Reaction Steps

A mixture of 4-amino-piperidine-1-carboxylic acid tert-butyl ester (440 mg; 2.2 mmol), 2-chloro-5-nitro-pyridine (316 mg; 2.0 mmol), and triethylamine (420 μL; 3.0 mL) is dissolved in tetrahydrofuran (6 mL) and the resulting mixture is irradiated in a mono-mode microwave oven for 6 hours at 120° C. The reaction mixture is then treated by water (10 mL) and the pH of the aqueous phase is set to 4-5 by the addition of aqueous 1N hydrochloric acid. The aqueous phase is then extracted with dichloromethane (2×20 mL), the combined organic layers are washed with brine (10 mL), dried over magnesium sulphate, filtered and concentrated under reduced pressure. The crude residue is then purified by column chromatography on silica gel (dichloromethane:ethyl acetate 1:0 and then 5:1) to afford the desired product (533 mg; 1.65 mmol).

Provenance & Evidence