Hypoxia‐Selective DNA Interstrand Cross‐Link Formation by Two Modified Nucleosides

Abstract

The clean crossed code: Two nitroimidazole-modified thymidines 1 a and 1 b were synthesized and incorporated into DNA oligomers. The 350 nm photolysis of 1 a and 1 b generated a 5-(2'-deoxyuridinyl)methyl radical that induced DNA interstrand cross-links (ICL; see scheme). A higher ICL yield was observed under hypoxic conditions than under aerobic conditions.