Imidazole-based potential Bi- and tridentate nitrogen ligands: synthesis, characterization and application in asymmetric catalysis.
Twelve new imidazole-based potential bi- and tridentate ligands were synthesized and characterized. Whereas in the first series the alpha-amino acid and imidazole moieties were linked by an amino bond, in the second series the tridentate ligands, containing two imidazole groups, were separated by an amide bond. The first series was obtained by the reductive amination of 2-phenylimidazole-4-carboxaldehyde with alpha-amino acid esters. The tridentate ligands were prepared from 2-phenylimidazole-4-carboxylic acid and chiral amines. In the Henry reaction, the amines were revealed as a more reactive species than the less nucleophilic amides, however the enantiomeric excesses were generally poor.
Sívek
Roman
R
Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, nám. Cs. legií 565, Pardubice, CZ-532 10, Czech Republic.
Bures
Filip
F
Pytela
Oldrich
O
Kulhánek
Jirí
J
D002384:Catalysis; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D017672:Nitrogen Compounds / Q000737:chemistry*; D013237:Stereoisomerism
D007093:Imidazoles; D008024:Ligands; D017672:Nitrogen Compounds; C029899:imidazole