The Emde degradation (also called Emde-reaction or Emde-reduction) is a method for the reduction of a quaternary ammonium cation to a tertiary amine with sodium amalgam:
This organic reaction was first described in 1909 by the German chemist Hermann Emde. It was for a long time of great importance in structure elucidation of many alkaloids, for example that of ephedrine. Alternative reducing agents exist for this reaction; for instance, lithium aluminium hydride.
See also Related reactions are the Hofmann elimination and the von Braun reaction
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