Synthesis and photooxidation of oligodeoxynucleotides containing 5-dimethylaminocytosine as an efficient hole-trapping site in the positive-charge transfer through DNA duplexes
hole migrated through the DNA bases and was trapped efficiently at the (DMA)C sites, where an enhanced oxidative strandcleavage occurred by hot piperidine treatment. The (DMA)C radical cation formed by hole transfer may undergo specific hydration and subsequent addition of molecular oxygen, thereby leading to its decomposition followed by a predominant strandcleavage at the (DMA)C site. This remarkable