Photoinduced Reactions of Styrylpyridine Derivatives for the in Situ Formation of Selective Ligands for Apyrimidinic DNA

The photocyclization reaction of sterically demanding styrylpyridine derivatives was investigated and shown to depend on the type of substituent. With this method, a 2,2-diphenyl-1,3-benzodioxolo-annelated benzo[c]quinolizinium was synthesized, and its association with regular and abasic site-containing DNA (AP-DNA) was investigated by absorption, fluorescence, circular and linear dichroism spectroscopy. Specifically, this ligand binds preferentially to AP-DNA relative to regular duplex DNA, and the AP-DNA/ligand complex is formed in situ upon irradiation of the styrylpyridine substrate in the presence of the DNA.