Polymer supported synthesis of novel benzoxazole linked benzimidazoles under microwave conditions: in vitro evaluation of VEGFR-3 kinase inhibition activity

Org Biomol Chem. 2011 Mar 21;9(6):1917-26. doi: 10.1039/c0ob00547a. Epub 2011 Feb 1.

Abstract

An efficient soluble polymer-supported method has been developed for the parallel synthesis of substituted benzimidazole linked benzoxazoles using focused microwave irradiation. The key step involves the amidation of 4-hydroxy-3-nitrobenzoic acid with polymer-immobilized o-phenylenediamine. Application of mild acidic conditions promoted the ring closure to furnish the benzimidazole ring. After hydrogenation of the nitro-group to amine, the resulted polymer conjugates underwent efficient ring closure with various alkyl, aryl and heteroaryl isothiocyanates to generate the polymer-bound benzimidazolyl benzoxazoles. The polymer-bound compounds were finally cleaved from the support to furnish benzimidazole linked benzoxazole derivatives. The efficacy of the resultant angular bis-heterocyclic library was studied against vascular endothelial growth factor receptor (VEGFR-3). The preliminary screening of these novel compounds exhibits moderate to high inhibition (IC(50) = 0.56-1.42 μM). This protocol provides an easy access to novel angular bis-heterocycles which have potential for the discovery of novel leads for targeted cancer therapeutics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzimidazoles / chemistry*
  • Benzoxazoles / chemical synthesis*
  • Cell Line, Tumor
  • Humans
  • Inhibitory Concentration 50
  • Microwaves
  • Models, Molecular
  • Molecular Structure
  • Polymers / chemistry*
  • Protein Kinase Inhibitors / chemical synthesis*
  • Protein Kinase Inhibitors / pharmacology
  • Vascular Endothelial Growth Factor Receptor-3 / antagonists & inhibitors*

Substances

  • Benzimidazoles
  • Benzoxazoles
  • Polymers
  • Protein Kinase Inhibitors
  • Vascular Endothelial Growth Factor Receptor-3