Synthesis and evaluation of 10-(3,5-dimethoxy)benzyl-9(10H)-acridone derivatives as selective telomeric G-quadruplex DNA ligands

A class of 9(10H)-acridone derivatives with terminal ammonium substituents at C2 (and C7) position(s) on the acridone ring were successfully synthesized. The relative affinities of the acridone compounds to G-quadruplex DNA have been investigated and the results showed that these compounds had a binding specificity for G-quadruplex over duplex sequences. The acridones with two terminal ammonium substituents had much more effects on the human telomeric G-quadruplex DNA than the corresponding acridone derivatives with one terminal ammonium substituent, and more positive charges introduced to the side chains can improve the formation and stabilization of the G-quadruplex.