Method for the stereoselective preparation of amino acid derivatives

Abstract

The invention relates to a process for the stereoselective preparation of amino acid derivatives, comprising a hydrogenation reaction of the compound of formula (III), alternatively its enantiomer, wherein R is (C 1 -C 8 )-alkyl; followed by a hydrolysis reaction to obtain L-mesityl alanine, alternatively its enantiomer D-mesityl alanine and, optionally, subjecting said compound to an amino group protection reaction, particularly as Fmoc. It also comprises Fmoc-L- or Fmoc-D- mesityl alanine as products per se, useful as intermediates in preparing peptides or peptide analogs with therapeutic or biological activity.

1 . Fmoc-(L)-mesityl alanine with an enantiomeric purity of >99% enantiomeric excess. 
     
     
         2 . Fmoc-(D)-mesityl alanine with an enantiomeric purity of >99% enantiomeric excess. 
     
     
         3 . A process for preparing peptides and/or peptide analogs with one or more mesityl alanine residues, comprising the following steps:
 a. Solid phase synthesis of the peptide, incorporating the mesityl alanine residues in the form of enantiomerically pure Fmoc-(L)-mesityl alanine and/or Fmoc-(D)-mesityl alanine according to any of  claims 1  and  2 , and   b. Cleaving the peptide from the polymeric support and simultaneously eliminating the protecting groups of the amino acids.   
     
     
         4 . The process according to  claim 3 , wherein the process is performed on an industrial scale.