Thermodynamic characteristics of NADH/NAD+ analogues in acetonitrile: 2-methyl, 4-methyl and 2,4-dimethyl 1-benzyl-dihydronicotinamides and the corresponding pyridinium species

Abstract

Procedures were elaborated for the syntheses of the title compounds. The thermodynamic changes brought about by each methyl substitution were then determined quantitatively. In acetonitrile, the respective one-electron oxidation and one-electron reduction potentials of the NADH and NAD+ analogues were obtained by means of direct and indirect (using ferrocene mediators) cyclic voltammetry. The redox potentials of formal hydride transfers were deduced from the studies of equilibrated reactions occurring between the analogues. The pKa's of the cation radicals ensued. Keywords: NADH/NAD+ methylated analogues, one-electron transfers, hydride transfer, thermodynamics.