Total syntheses of thiocoraline and BE-22179 and assessment of their DNA binding and biological properties

J Am Chem Soc. 2001 Jan 31;123(4):561-8. doi: 10.1021/ja003602r.

Abstract

Full details of the total syntheses of thiocoraline (1) and BE-22179 (2), C(2) symmetric bicyclic octadepsipeptides possessing two pendant 3-hydroxyquinoline chromophores, are described in which their relative and absolute stereochemistry were established. Key elements of the approach include the late-stage introduction of the chromophore, symmetrical tetrapeptide coupling, macrocyclization of the 26-membered octadepsipeptide conducted at the single secondary amide site following disulfide formation, and a convergent assemblage of the tetradepsipeptide with introduction of the labile thiol ester linkage in the final coupling reaction under near racemization free conditions. By virtue of the late-stage introduction of the chromophore and despite the challenges this imposes on the synthesis, this approach provides ready access to a range of key chromophore analogues. Thiocoraline and BE-22179 were shown to bind to DNA by high-affinity bisintercalation analogous to echinomycin, but with little or no perceptible sequence selectivity. Both 1 and 2 were found to exhibit exceptional cytotoxic activity (IC(50) = 200 and 400 pM, respectively, L1210 cell line) comparable to echinomycin and one analogue, which bears the luzopeptin chromophore, was also found to be a potent cytotoxic agent.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemical synthesis*
  • Anti-Bacterial Agents / metabolism
  • Anti-Bacterial Agents / pharmacology
  • Antibiotics, Antineoplastic / chemical synthesis
  • Antibiotics, Antineoplastic / metabolism
  • Antibiotics, Antineoplastic / pharmacology
  • Cattle
  • Cell Survival / drug effects
  • DNA / metabolism*
  • Depsipeptides*
  • Echinomycin / metabolism
  • Echinomycin / pharmacology
  • HIV-1 / enzymology
  • Inhibitory Concentration 50
  • Mice
  • Peptides*
  • Reverse Transcriptase Inhibitors
  • Tumor Cells, Cultured

Substances

  • Anti-Bacterial Agents
  • Antibiotics, Antineoplastic
  • Depsipeptides
  • Peptides
  • Reverse Transcriptase Inhibitors
  • thiocoraline
  • BE 22179
  • Echinomycin
  • DNA
  • calf thymus DNA