10.1021/ol027026a.s001 Kallanthottathil G. Rajeev Kallanthottathil G. Rajeev Martin A. Maier Martin A. Maier Elena A. Lesnik Elena A. Lesnik Muthiah Manoharan Muthiah Manoharan High-Affinity Peptide Nucleic Acid Oligomers Containing Tricyclic Cytosine Analogues<sup>†</sup> American Chemical Society 2002 PNA oligomers tricyclic cytosine analogues phenoxazine PNA modifications DNA targets acid targets RNA mismatch discrimination 2002-11-15 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/High-Affinity_Peptide_Nucleic_Acid_Oligomers_Containing_Tricyclic_Cytosine_Analogues_sup_sup_/3744807 Peptide nucleic acid (PNA) monomers containing the tricyclic cytosine analogues phenoxazine, 9-(2-aminoethoxy)phenoxazine (G-clamp), and 9-(3-aminopropoxy)phenoxazine (propyl-G-clamp) have been synthesized. The modified nucleobases were incorporated into PNA oligomers using Boc-chemistry for solid-phase synthesis. PNAs containing single G-clamp modifications exhibit significantly enhanced affinity toward RNA and DNA targets relative to unmodified PNA while maintaining mismatch discrimination. These PNA G-clamp modifications exhibit the highest increase in affinity toward nucleic acid targets reported so far for PNA modifications.