title: An efficient method for solution-phase parallel synthesis of 2-quinoxalinol salen Schiff-base ligands.
abstract: 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.
authors.affiliation: Department of Chemistry and Biochemistry, College of Science and Mathematics, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849-5319, USA.
authors.forename: Xianghong
authors.initials: X
authors.lastname: Wu
authors.forename: Anne E V
authors.initials: AE
authors.lastname: Gorden
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D016208:Databases, Factual; D005029:Ethylenediamines / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000737:chemistry; D012545:Schiff Bases / Q000737:chemistry; D012996:Solutions
chemical_list: D000447:Aldehydes; D000588:Amines; D005029:Ethylenediamines; D008024:Ligands; D011810:Quinoxalines; D012545:Schiff Bases; D012996:Solutions; C013243:salicylaldehyde; C011452:disalicylaldehyde ethylenediamine