Ethanol → (S)-Ethyl piperidine-2-carboxylate hydrochloride

Beteiligte Stoffe

Reaktionsschritte

Crude (S)-(-)-2-piperidinecarboxylic acid (19.5 g, prepared as described in example 26) was suspended in ethanol (250 ml), and thionyl chloride (40 ml, 0.46 mol) was added dropwise. After addition was complete, the suspension was heated at reflux temperature for 2 h. The mixture was filtered hot, and the filtrate was cooled to room temperature. Filtration and evaporation in vacuo afforded an oil, which was crystallised by rubbing. Ethanol (10 ml) was added, followed by slow addition of diethyl ether (150 ml). The precipitated solid was filtered off, washed with diethyl ether and dried by suction to give 13.8 g (35% calculated from 2-piperidinecarboxylic acid) (S)-(-)-2-piperidinecarboxylic acid ethyl ester hydrochloride.

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