The photoreaction of a styrylpyridine derivative leads to a DNA-binding benzoquinolizinium derivative with selectivity towards abasic site-containing DNA (AP-DNA), as caused by the sterically demanding substituents. Notably, the DNA binding is accomplished by photoinduced in situ formation of the ligand in the presence of AP-DNA.

Abstract

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.