Mb. Taraban et al., THE MECHANISMS OF THE OXIDATION OF NADH ANALOGS .1. PHOTOCHEMICAL OXIDATION OF N-UNSUBSTITUTED 1,4-DIHYDROPYRIDINES BY VARIOUS ACCEPTORS, Journal of photochemistry and photobiology. A, Chemistry, 73(2), 1993, pp. 151-157
The reactivity of different active centers has been studied during the
photo-oxidation of N-unsubstituted 1,4-dihydropyridines (1,4-DHPs) by
various electron acceptors. The participation of that or another reac
tive center (N-H, (C-4)-H, (C-3)-CO group) in the reaction has been ob
served, depending on the type of process, 1,4-DHP structure, medium po
larity and related properties. In the case of photo-initiated interact
ion with electron acceptors, the elementary mechanism of the process i
ncludes the sequential stages of electron, proton and hydrogen atom tr
ansfer (e-, H+, H.) if the electron acceptors are quinones which are a
ble to form charge transfer complexes with the initial 1,4-DHP. When a
cceptors of another type are used, the primary act of the photo-oxidat
ion process is the abstraction of hydrogen atoms from the C-4 position
of the 1,4-DHP, and the oxidation takes place as the two-stage (H., H
-) process.