Hydroacridines. Part 16.1 Steric effect in the polarographic reduction of N-epimeric amine oxides derived from (4aα,8aβ,9aβ,10aα)- and (4aα,8aα,9aβ,10aα)-tetradecahydro-10-methylacridine

Abstract

The electrochemical reduction of (4aα,8aβ,9aβ,10β,10aα)- (1a), (4aα,8aβ,9aβ,10α,10aα)- (1e), (4aα,8aα,9aβ,10β,10aα)- (2a) and (4aα,8aα,9aβ,10α,10aα)-tetradecahydro-10-methylacridine-10-oxide (2e) has been investigated by dc and ac polarography. For both of these N-epimeric pairs of amine oxides, the polarographic behaviour is influenced in the same way by the steric orientation of the N–O bond. So, whereas the epimers with axial oxygen (1a and 2a) give normal, single-wave polarographic curves, both epimers with equatorial oxygen (1e and 2e) give unusually shaped, double-wave curves. The steric configuration of the tricyclic framework affects only the values of the half-wave potentials and not the shape of the polarographic curves. These results suggest that polarography could be used to assign the steric configurations of the N–O bonds in saturated heterocyclic amine oxides, or to support assignments achieved by other methods.