High-performance liquid chromatographic separation of unusual amino acid enantiomers derivatized with (1S,2S)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl-isothiocyanate

A new chiral derivatizing agent (CDA), (1S,2S)-1,3-diacetoxy-1-(4-nitrophen yl)-2-propylisothiocyanate, (S,S)-DANI, was applied to the separation of th e enantiomers of unusual amino acids containing two chiral centers. Differe nt beta-methyl-alpha-amino acids (beta-MePhe, beta-MeTyr and beta-MeTrp) an d beta-amino acids with cycloalkane skeletons (2-aminocyclopentanecarboxyli c acid and 2-aminocyclohexanecarboxylic acid) were derivatized and the thio urea derivatives produced were separated by reversed-phase high-performance liquid chromatography. The applicability of this new CDA in the separation of unusual amino acids is demonstrated. The four stereoisomers of the inve stigated amino acids (except beta-MePhe) could be separated in one chromato graphic run.