Liquid-phase synthesis of polyamide nucleic acids (PNA)

Abstract Three liquid-phase processes for the elaboration of short orthogonally protected PNA have been devised. Two of these methods are similar to the convergent and divergent approaches in peptide synthesis. The third process consists in building a fully protected polyamide backbone, by using as many different and orthogonal protecting groups as there are different types of nucleic bases in the targeted polyPNA. Simultaneous and selective cleavage of one kind of protecting group allows the simultaneous attachment of several identical nucleobase units.