Sulfuric Acid → 8-Benzyl-2,8-diazaspiro[4.5]decane-1,3-dione

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Reaction Steps

Acetic acid (56.8 ml) and sulfuric acid (11.8 ml) are added to 1-benzyl-4-cyanomethyl-piperidine-4-carbonitrile (27.2 g, 0.114 mmol) at ambient temperature. The reaction mixture is stirred at 125 C.° for 1 h, cooled down to the room temperature and added to saturated NaOH aq. to adjust to pH 6.0. The mixture is extracted with dichloromethane. The combined extracts are washed with H2O and brine, dried over sodium sulfate and evaporated down to give 8-benzyl-2,8-diaza-spiro[4.5]decane-1,3-dione (three steps yield: 81.8%).

Provenance & Evidence