Triethylamine → tert-Butyl 9-(pyridin-4-yl)-3,9-diazaspiro[5.5]undecane-3-carboxylate

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Reaction Steps

tert-Butyl-3,9-diazaspiro[5.5]undecane-3-carboxylate (1 g, 3.931 mmol), 4-chloro-pyridinium chloride (1.765 g, 11.794 mmol) and triethylamine (2.2 ml, 15.725 mmol) were refluxed for 15 h in 1-butanol (50 ml). Saturated sodium hydrogen carbonate solution (30 ml) and ethyl acetate (80 ml) were added, the phases were separated, and the aqueous phase was extracted with ethyl acetate (2×80 ml). The combined organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified by column chromatography (silica gel, ethyl acetate/-hexane/methanol/ammonia (25% aq.), 400:40:40:1). Yield: 0.52 g (39%)

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