| Popis: |
The polarographic reduction potentials were determined by classical polarography, millicoulometry, preparative electrolysis, and cyclical voltammetry, and the course of the electrochemical process for nonquaternized and quaternized pyrophthalones in 20% buffer solutions in aqueous dimethylformamide was studied. In the case of α and γ isomers of pyrophthalones, two-electron irreversible electrical reduction leads to the formation of an indan-1-on-3-yl-1,4-dihydropyridine, which exists in two protolytic forms. The compound was isolated and its structure was proved by means of mass spectrometry. The polarographic reduction of β-pyrophthalones is similar to the electrical reduction of 2-phenylindane-1,3-dione. The tautormeric-protolytic equilibria of quaternized and nonquaternized α-, β-, and γ-pyrophthalones were studied, and it was ascertained that individual tautomeric-protolytic forms participate in the electrochemical process at various pH values. |
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