Electronic structures and reactivities of derivatives of 1,4-dihydropyridines. 3. Enthalpies of elementary processes in the 1,4-dihydronicotinamide series

✍ Scribed by A. M. Nesterenko; N. I. Buryak; O. M. Polumbrik; A. A. Yasnikov

• Publisher: Springer US
• Year: 1988
• Tongue: English
• Weight: 352 KB
• Volume: 24
• Category: Article
• ISSN: 0009-3122
• DOI: 10.1007/bf00475566

✦ Synopsis

The heat effectsof the elementary processes involved in electron and hydrogen transfer with the participation of 1,4-dihydropyridines were calculated by the semiempirical MINDO/3 method. The effect of a number of side and parallel processes on the kinetic principles is discussed in the case of the oxidation of l-methyl-l,4-dihydronicotinamide. The calculated and experimental data are compared.

Additional data on the thermochemical characteristics of the corresponding elementary processes [4,5 ] are necessary in view of the s and nonequilibrium occurrence of the funcdamentally important (for biochemistry) reactions involved in the oxidation of 1,4-dihydropyridines [2, 3]o

The principal processes involved in the interconversion of a series of derivatives of 1,4-dihydropyridines in the presence of oxidizing agents (Ox) or reducing agents (Red) and bases (B) or proton-donor compounds (H+X-), as well as hydrogen atom acceptors (A), can be represented by the scheme ~ yH + PyH~" (t pyH: ~.~,=b::~. AH X//~ers x /,,,.p,. '

'r F,,,H)

where PyH 2 is l-methyl-l,4-dihydronicotinamide, PyH2 +" is its cation radical, PyHa + is the C(s)-protonated form of PyH2, PyH" is the corresponding pyridinyl radical, and PyH + is the 1 -methyl-3-car bamidopyr idinium cation.

On the basis of calculations of the electronic structures and physicochemical properties [i, 5] we accomplished an analysis of the energy characteristics of the most important ele-*See [i] for Communication 2.