Liquid-phase synthesis of polyamide nucleic acids (PNA)

Three liquid-phase processes for the elaboration of short orthogonally prot ected PNA have been devised. Two of these methods are similar to the conver gent and divergent approaches in peptide synthesis. The third process consi sts in building a fully protected polyamide backbone, by using as many diff erent and orthogonal protecting groups as there are different types of nucl eic bases in the targeted polyPNA. Simultaneous and selective cleavage of o ne kind of protecting group allows the simultaneous attachment of several i dentical nucleobase units. (C) 1999 Elsevier Science Ltd. All rights reserv ed.