Erlenmeyer-Plöchl azlactone and amino acid synthesis

Overview
The Erlenmeyer-Plochl azlactone and amino acid synthesis, named after Friedrich Gustav Carl Emil Erlenmeyer who partly discovered the reaction, is a series of chemical reactions which transform glycine to various other amino acids via an oxazolone and an azlactone.



Hippuric acid self-condenses in the presence of acetic anhydride to 2-phenyl-oxazolone. This intermediate also has two acidic protons and reacts with benzaldehyde, acetic anhydride and sodium acetate to a so-called azlactone. This compound on reduction gives access to phenylalanine.

Scope
In one study the Erlenmeyer amino acid synthesis was used in the heart of an L-m-tyrosine synthesis