Synthesis of cyclic Py-Im polyamide libraries

J Org Chem. 2013 Jan 4;78(1):124-33. doi: 10.1021/jo302053v. Epub 2012 Nov 2.

Abstract

Cyclic Py-Im polyamides containing two GABA turn units exhibit enhanced DNA binding affinity, but extensive studies of their biological properties have been hindered due to synthetic inaccessibility. A facile modular approach toward cyclic polyamides has been developed via microwave-assisted solid-phase synthesis of hairpin amino acid oligomer intermediates followed by macrocyclization. A focused library of cyclic polyamides 1-7 targeted to the androgen response element (ARE) and the estrogen response element (ERE) were synthesized in 12-17% overall yield. The Fmoc protection strategy also allows for selective modifications on the GABA turn units that have been shown to improve cellular uptake properties. The DNA binding affinities of a library of cyclic polyamides were measured by DNA thermal denaturation assays and compared to the corresponding hairpin polyamides. Fluorescein-labeled cyclic polyamides have been synthesized and imaged via confocal microscopy in A549 and T47D cell lines. The IC(50) values of compounds 1-7 and 9-11 were determined, revealing remarkably varying levels of cytotoxicity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemistry*
  • Cell Line
  • Cyclization
  • Fluorescein / chemistry*
  • Humans
  • Imidazoles / chemical synthesis*
  • Imidazoles / chemistry
  • Inhibitory Concentration 50
  • Microwaves
  • Molecular Sequence Data
  • Nucleic Acid Denaturation
  • Nylons / chemical synthesis*
  • Nylons / chemistry*
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry
  • Solid-Phase Synthesis Techniques
  • gamma-Aminobutyric Acid / chemistry*

Substances

  • Amino Acids
  • Imidazoles
  • Nylons
  • Pyrroles
  • gamma-Aminobutyric Acid
  • Fluorescein