The photoreactivity of the caged precursors of oligonucleotides containing C4'-oxidized abasic site and reaction of the generated lesion.

The C4'-oxidized abasic site (1) is one of the oxidatively damaged DNA lesions by antitumor bleomycins (BLMs) and the acyclic keto aldehyde incorporated in DNA might react with DNA interacting biomolecules. We synthesized oligodeoxynuceotides 3-caged-1 and 3-caged-2 as caged precursors of 3, an ODN containing 1, to study the reactivities of 3 with amine. Irradiation of double stranded 3-caged-1 led to efficient formation of 3 compared to its single stranded form. Similarly, 3-caged-2 and its duplex afforded 3. With 3-caged-2, yields of 3 were lower compared to 3-caged-1. Formation of the duplex slowed decaging rate down but the yield of 3 was higher than that of single stranded 3-cage-2. Reaction of the obtained 3 with amine resulted in the formation of lactam 2b in good yield.