Design and stereoselective synthesis of four peptide nucleic acid monomers with cyclic structures in backbone

Abstract

Four isomers of the monomer of peptide nucleic acid (PNA) were derived from (2S,4R)-4-hydroxyproline; they had different stereochemistries at the C2 and C4 positions in the pyrrolidine ring. These different backbone conformations corresponding to four different stereochemistries were realized through a combination of inversions at the C2 and the C4 positions in pyrrolidine ring. The obtained backbone frameworks were reacted with N-benzoyl thymine to give the corresponding PNA monomers. Spectroscopic comparison of the resultant monomers confirmed their stereochemistries. J. Heterocyclic Chem., (2011).