Stereoselective Synthesis of a Thymine Derivative of (<i>S</i>)-2-Hydroxy-4-(2-aminophenyl)butanoic Acid. A Novel Building Block for the Synthesis of Aromatic Peptidic Nucleic Acid Oligomers¹

Abstract

The synthesis of a thymine derivative of (S)-2-hydroxy-4-(2-aminophenyl)butanoic acid, compound 1, was achieved in high enantiomeric purity. The acyclic pyrimidine analog (S)-1 is a useful building block for the synthesis of a novel class of oligomers, the aromatic peptide nucleic acids (APNA, Scheme 1). The APNA tetramer 18 was prepared from the amino acid monomer (S)-1 using classical peptide synthesis. UV absorption spectra and 1H NMR data of this tetramer suggested that base stacking interactions in the APNA oligomers may be favorable.