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Henryho reakce: Nové měďnaté komplexy na bázi mono- a bis(imidazolyl)pyridinů
Authors: Keder Roman | Drabina Pavel | Hanusek Jiří | Sedlák Miloš
Year: 2005
Type of publication: článek ve sborníku
Name of source: ChemZi
Publisher name: Slovenská chemická spoločnosť
Place: Bratislava (Slovenská republika)
Page from-to: 214-215
Titles:
Language Name Abstract Keywords
cze Henryho reakce: Nové měďnaté komplexy na bázi mono- a bis(imidazolyl)pyridinů In recent years, it intensively increases development of synthesis and characterisation of new chiral ligands and their transition metal complexes. These complexes are especially used as a homogeneous catalysts in asymmetric synthesis. We have prepared new ligands based on mono- and bis(imidazolonyl)pyridines, from optically pure 2-amino-2,3-dimethylbutanamides and ethyloxycarbonyl pyridine 2-carboxylic acid or pyridine-2,6-dicarboxylic acid dichloride, followed by subsequent ring closure reaction giving imidazolone cylce. The last step was N-alkylation of imidazolones by different alkylation agents. Ligands prepared in this way were characterised using 1H and 13C NMR spectroscopy. Finally were prepared complexes of ligands with cobalt(II) and copper(II) acetate. These metal complexes were used as enantioselective catalysts for Henry?s reaction. The monoimidazolonylpyridines ligands gives nitroaldol products with yield 49 ? 93% and maximal optical yield 15,6%, however bis(imidazolonyl)pyridines gives only racemic products. Imidazolonpyridiny, Mědnaté komplexy, Henryho reakce
eng Henry΄s reaction: New copper(II) complexes based on mono- and bis(imidazolyl)pyridines In recent years, it intensively increases development of synthesis and characterisation of new chiral ligands and their transition metal complexes. These complexes are especially used as a homogeneous catalysts in asymmetric synthesis. We have prepared new ligands based on mono- and bis(imidazolonyl)pyridines, from optically pure 2-amino-2,3-dimethylbutanamides and ethyloxycarbonyl pyridine 2-carboxylic acid or pyridine-2,6-dicarboxylic acid dichloride, followed by subsequent ring closure reaction giving imidazolone cylce. The last step was N-alkylation of imidazolones by different alkylation agents. Ligands prepared in this way were characterised using 1H and 13C NMR spectroscopy. Finally were prepared complexes of ligands with cobalt(II) and copper(II) acetate. These metal complexes were used as enantioselective catalysts for Henry?s reaction. The monoimidazolonylpyridines ligands gives nitroaldol products with yield 49 ? 93% and maximal optical yield 15,6%, however bis(imidazolonyl)pyridines gives only racemic products. Imidazolonepyridines, Copper(II) complexes, Henry΄s reaction