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Polarographic, potentiometric and kinetic studies of NAD model compounds

University of British Columbia

The effects of varying the 1- and 3-substituents of NAD⁺ (I) model compounds on reactions (1) through (4) have [Chemical Diagrams] been investigated. The one-electron reduction in reaction (1) was observed polarographically. A reaction constant ρ* of +3.7 was found for the effect of 1-substituents and a reaction constant p of +11 to +12 was found for the effect of 3-substituents. The potential of the two-electron reduction of pyridinium ions in reaction (2) was measured potentio-metrically. Reaction constants of +2.8 and +9 to +11 were found for the effects of 1- and 3-substituents, respectively. Reaction constants of -1.9 and -6 were found for the effects of 1- and 3-substituents on the rates of oxidation of 1,4-dihydropyridines by flavins, reaction (3) . A similar reaction constant of -2.0 to -2.6 was found for the effect of 1-substituents on the acid decomposition of 1,4-dihydro-vridines, reaction (4). These results suggest that the mechanism of oxidation of 1,4-dihydropyridines by flavins may be more complex than the commonly accepted mechanism of hydride transfer. Reactions (1) through (4) were also investigated using WAD⁺, nicotinamide mononucleotide (NMN) and two 1,1'-alkylenebis(3-carbamoylpyridinium) compounds (II). The {Chemical Diagrams] oxidation-reduction properties of these four compounds be explained by considering the inductive effects of the 1-substituents.

Text

2010-02-08

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http://hdl.handle.net/2429/19759

Chemistry

University of British Columbia

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