A Crystallization-Induced Asymmetric Transformation using Racemic Phenyl Alanine Methyl Ester Derivatives as Versatile Precursors to Prepare Amino Acids

L-tyrosine and l-dopa are the precursors in the biological synthesis of amineneurotransmitters. on the other hand, phenylalanine as an aromatic amino acid (aaa)is a precursor in the synthesis of l-tyrosine and l-dopa. for some substrates such asamino acids, resolution by the formation of diastereomers offers an attractivealternative. among different methods in this case, crystallization-induced asymmetrictransformation (ciat) that is in situ racemization and selective crystallization of areaction product can be a good choice. using this method, preparation of l-tyrosineand l-dopa has been reported. in the synthetic route, racemic phenyl alanine methylester derivatives as versatile precursors were prepared by reducing azlactone derivativeswith mg in methanol as a reducing reagent and then in the resolution step (s)-enantiomer of l-dopa (3,4-dihydroxyphenylalanine) and l-tyrosine (4-hydroxyphenylalanine) were achieved via salt formation with (2r,3r)-tartaric acid inthe presence of 5-nitro salicylaldehyde in good yield and high optical purity.