Triethylamine → 4-Phenyl-2,8-diazaspiro[4.5]decan-1-one

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Reaction Steps

To a solution of ethyl isonipecotate (20 g, 127 mmol) in dioxane:water (1:1, 120 mL) was added triethylamine (12.87 g, 127 mmol) at 0° C. followed by di-tert-butyl dicarbonate (35.2 g, 161 mmol) and the resulting mixture maintained at this temperature for 2 h. The product was then extracted with ethyl acetate (3×100 mL) and the combined organic extracts washed with HCl (1 N, 100 mL), brine (100 mL), dried over sodium sulfate, filtered and evaporated. Purification by Kugelrohr distillation afforded the title compound (29.0 g, 89%) as a colourless liquid, bp 140° C. at 0.13 mbar. MS: m/e=275.2 (M+NH4).

Provenance & Evidence