Enamines. 8. Polarographic study of the reactions of a number of enamino ketones with nucleophilic reagents

The hydrolysis and hydrazinolysis of cyclic enamino ketones of the pyrrolidine, piperidine, and hexahydroazepine series, as well as their noncyclic analogs, were investigated. It is shown that these processes have several principles in common. A bell-shaped dependence of kobs on the pH of the medium is characteristic for hydrolysis; the reaction of the enamino ketones with hydrazine hydrate in absolute ethanol is accelerated in the presence of p-toluenesulfonic acid. It is shown that the rates of hydrolysis and hydrazinolysis depend on the size of the saturated azaheteroring and change in the order 6 > 5 > 7. A possible mechanism for the processes in which the slow step is C-protonation and(or) attack by the nucleophilic reagent in the enamine position is discussed.See [1] for Communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 3, pp. 352–356, March, 1981.