Synthesis and G-Quadruplex-Binding Properties of Defined Acridine Oligomers

Figure 2

Solid-phase synthesis of dimer and trimer acridine derivatives. (a) (i) Fmoc-Sar-OH, PyBOP, DIEA; (ii) 20% piperidine, DMF; (iii) Boc–NH–(CH₂)₆–OCH₂CH₂COOH, PyBOP, DIEA; (b) (i) 40% TFA, DCM; (ii) Fmoc-Aeg(Boc)-OH, PyBOP, DIEA; (iii) Repeat steps (i) and (ii) n times; (c) (i) 40% TFA, DCM; (ii) Ac₂O, DIEA, DMF; (d) (i) 20% piperidine, DMF; (ii) Fmoc-Gly-OH, PyBOP, DIEA; (e) (i) 20% piperidine, DMF; (ii) acridine-9-carboxylic acid, PyBOP, DIEA; (f) anhydrous HF (0°); (g) 32% aqueous NH₃.