Aminoethylprolyl (aep) PNA: mixed purine/pyrimidine oligomers and binding orientation preferences for PNA:DNA duplex formation

structure in text] The synthesis of (2S,4S)- and (2R,4S)-aepPNA monomers of adenine, guanine, and cytosine (3-5) and their incorporation at appropriate positions into aegPNA sequence 7 leads to mixed aeg-aep backbone/mixed nucleobase PNAs 8-11. The thermal stabilities of the derived duplexes with DNA are found to be dependent on nucleobase and backbone stereochemistry.