An Efficient Method for Solution-Phase Parallel Synthesis of 2-Quinoxalinol Salen Schiff-Base Ligands

  • 10.1021/cc070021q
  • Journal of Combinatorial Chemistry
  • p 601-608, Volume 9, Issue 4,
  • journal-article
A solution-phase parallel method for the synthesis of 2-quinoxalinol salen ligands was designed and optimized. The synthesis begins with commercially available 1,5-difluoro-2, 4-dinitrobenzene (DFDNB) and employs a sequence of five straightforward and high-yielding reaction steps. Simple laboratory techniques with low sensitivity to water or air for solution-phase parallel reactions were coupled with convenient workup and purification procedures to give high-purity and yield a small ligand library of 20 compounds. The final step, a Schiff-base condensation of an aldehyde with the diaminoquinoxaline results in a new category of ligands for metal coordination or of potential bioactivity, based on the skeleton 2,2‘-(1E,1‘E)-(quinoxaline-6,7-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)diphenol. The approach described here is easily adaptable for parallel synthesis of a larger library.


Excellent reproducibility, some improvements suggested

This article describes an efficient method for solution-phase parallel synthesis of 2-quinoxalinol salen Schiff-base ligands. The novelty of this article is the synthesis of a new category of ligands using Schiff-base condensation of an aldehyde with a diaminoquinoxaline.