Convenient Method for the Synthesis of a Flexible Cyclic Polyamide for Selective Targeting of c-myb G-quadruplex DNA

A convenient efficient method for synthesis of a flexible cyclic polyamide (c beta, 1) was developed through cyclodimerization. Electrospray ionization mass spectrometry and nuclear magnetic resonance results showed that 1 selectively binds to the c-myb G-quadruplex with high affinity, and there was no binding with the ILPR, bcl-2, and c-kit G-quadruplexes. This is the first time that a flexible cyclic polyamide was found to have high selectivity for the c-myb G-quadruplex.