Synthesis of G-N2-(CH2)3-N2-G Trimethylene DNA Interstrand Cross-Links

The synthesis of G-N(2)-(CH(2))(3)-N(2)-G trimethylene DNA interstrand cross-links (ICLs) in a 5'-CG-3' and 5'-GC-3' sequence from oligodeoxynucleotides containing N(2)-(3-aminopropyl)-2'-deoxyguanosine and 2-fluoro-O(6)-(trimethylsilylethyl)inosine is presented. Automated solid-phase DNA synthesis was used for unmodified bases and modified nucleotides were incorporated via their corresponding phosphoramidite reagent by a manual coupling protocol. The preparation of the phosphoramidite reagents for incorporation of N(2)-(3-aminopropyl)-2'-deoxyguanosine is reported. The high-purity trimethylene DNA interstrand cross-link product is obtained through a nucleophilic aromatic substitution reaction between the N(2)-(3-aminopropyl)-2'-deoxyguanosine- and 2-fluoro-O(6)-(trimethylsilylethyl)inosine-containing oligodeoxynucleotides.