(Chemical Equation Presented) Bleomycin-induced oxidative DNA damage under limited oxygen conditions results in the formation of the C4′-oxidized abasic site (1). We synthesized the oligodeoxynucleotides (ODN) 5, which contains 4′-o-nitrobenzyloxythymidine (3), and 6, which contains 2-nitrobenzyloxy-4′-methoxy-2′-deoxy-D-ribofuranoside (4) as the caged precursors of 7, an ODN containing 1, to study its reactivity with amines Photoirradiation of the single- and double-stranded 5 led to the formation of 7. Uncaging of the duplex was faster and the yield of 7 was higher with the double-stranded than with the single-stranded ODN. It was suggested that a low dielectric environment of the o-nitrobenzyloxy group in the minor groove of the duplex might accelerate the uncaging rate. Similarly, 6 and its duplex yielded 7 by photoirradiation However, the yields of 7 were lower than those of 5, and duplex formation slowed the uncaging rate. Reaction of the obtained 7 with an amine resulted in the formation of the lactam 2b in good yield in both single- and double-stranded forms, showing that amine modification of biomolecules by an ODN containing 1 is possible under physiologic conditions.
All Science Journal Classification (ASJC) codes
- Organic Chemistry