Electrochemical reductions of methyl azinyl ketoximes on mercury

Electroreductions of hydroxyimino group of methyl hetaryl (pyridin-2-yl, py ridazin-3-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazinyl) ketoximes on mercu ry electrodes were studied using de polarography, coulometry and preparativ e electrolysis. Depending on pH, double-protonated, single-protonated and n eutral forms of the ketoximes are transformed in a four-electron reduction to the corresponding amine. The second nitrogen in the diazine ketoximes fa cilitates 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 t he heteroaromatic ring in the diazine ketoximes proceeds at more negative p otentials than the reduction of the oxime group.