An Improved Route for the Synthesis of Guanine Quadruplex Ligand Phen-DC3

The recognition of noncanonical DNA and RNA architectures such as guanine quadruplexes by small molecule ligands has become a promising strategy for anticancer and antiviral applications in recent years, leading to an exponential increase in the number of quadruplex ligands reported in the literature. There is consequently a need for ‘benchmark’ compounds which can be used as controls to facilitate comparisons between novel and previously reported ligands. One candidate for this role is Phen-DC3, which binds with high affinity and selectivity to guanine quadruplexes. To encourage its use in this role, an alternate synthetic route for the production of Phen-DC3 that may be more appropriate for implementation on a large scale is reported. This pathway eliminates the need for several hazardous reagents and increases the overall synthetic yield from 21% to a maximum of 43%.