Synthesis and characterization of isotopically enriched pyrimidine deoxynucleoside oxidation damage products

Oxidative damage to DNA is an established source of genomic instability. In this paper, we describe the synthesis and characterization of several pyrimidine deoxynucleoside oxidation damage products, enriched with stable isotopes. These products include the 2'-deoxynucleoside derivatives of 5- (hydroxymethyl)uracil, 5-formyluracil, 5-hydroxyuracil, 5-(hydroxymethyl)- cytosine, 5-formylcytosine, and 5-hydroxycytosine. The common precursor is 2'-deoxy-2''-deutero[1,3-¹⁵N]uridine. Additional stable isotopes are added during functional group conversions. Characterization of these derivatives includes mass spectrometry and ¹H and ¹⁵N NMR spectroscopy. Proton and nitrogen NMR studies reported here allow an examination of the influence of the modification on sugar conformation and tautomeric equilibrium, properties likely to be important in understanding the biological consequences of these DNA damage products.