Collect. Czech. Chem. Commun. 2000, 65, 1630-1642

Electrochemical Reductions of Methyl Azinyl Ketoximes on Mercury

Radek Cibulkaa, František Liškaa and Jiří Ludvíkb,*

a Department of Organic Chemistry, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
b J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8


Electroreductions of hydroxyimino group of methyl hetaryl (pyridin-2-yl, pyridazin-3-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazinyl) ketoximes on mercury electrodes were studied using dc polarography, coulometry and preparative electrolysis. Depending on pH, double- protonated, single-protonated and neutral forms of the ketoximes are transformed in a four-electron reduction to the corresponding amine. The second nitrogen in the diazine ketoximes facilitates reduction of the oxime group in comparison with methyl pyridin-2-yl ketoxime. Reducibility of the oximes correlates with the enhancement of their hydrolytic activity towards 4-nitrophenyl acetate. The reduction of the heteroaromatic ring in the diazine ketoximes proceeds at more negative potentials than the reduction of the oxime group.

Keywords: Electrochemistry; Reductions; Oximes; Pyridines; Diazines; Polarography; Coulometry; Ester hydrolysis; Micellar catalysts.

References: 30 live references.