Orthogonal Synthesis of Xeno Nucleic Acids.

Sequence-defined peptide triazole nucleic acids (PTzNA) were synthesized by means of a solid-phase orthogonal "AB+CD" iterative strategy. In this approach, AB and CD building blocks containing carboxylic acid (A), azide (B), alkyne (C), and primary amine (D) functions are assembled together by successive copper-catalyzed azide-alkyne cycloaddition (CuAAC) and acid-amine coupling steps. Different PTzNA genetic sequences were prepared using a library of eight building blocks (i.e., four AB and four CD building blocks).