Diisopropylethylamine → tert-Butyl 2-(pyridin-4-yl)-2,9-diazaspiro[5.5]undecane-9-carboxylate

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Reaction Steps

tert-Butyl 2,9-diazaspiro[5.5]undecane-9-carboxylate (1 g, 3.931 mmol), 4-chloropyridinium chloride (1.765 g, 11.794 mmol) and N-ethyl-diisopropylamine (2.7 ml, 15.724 mmol) were refluxed in 2-propanol (8 ml) for 15 h, saturated NaHCO3 solution (20 ml) and ethyl acetate (8 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 sodium sulfate and concentrated in vacuo. The crude product was purified by column chromatography (silica; ethyl acetate/methanol/ammonia (25 aq.) 100:10:0.25). Yield: 0.67 g (51.4%)

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