Synthesis of cNDI‐Peptide‐Dimer as a G4 Cluster‐Selective Binder and its Interaction with G4 Dimer

The amino acid unit carrying cyclic naphthalene diimide (cNDI) was synthesized by linking the amino moiety of cNDI as a G4‐specific ligand with the γ‐carboxylic acid moiety of Fmoc‐Glu. cNDI‐peptide‐dimer, 1 was synthesized by peptide synthesizer using this unit. 1 exhibited an extremely strong binding constant of the order of 10 8 M − 1 with telomeric G4 dimer, probably due to cooperative stacking of the its two G4 planes. It also showed an IC 50 at the nM level by the TRAP assay. The results obtained here are expected to enable the design of peptide ligands with multiple cNDI sites targeting the G4 cluster by using the amino acid units of cNDI.