13C and 1H NMR study of N‐5′‐methylsalicylideneanilines

The 13C and 1H NMR spectra of six N‐5′ ‐methylsalicylideneanilines have been studied. Correlations of the chemical shifts of C‐α (azomethine carbon) and C‐4′ with the σ, F, R, σ1 and σ parameters have been examined for N‐5′‐methylsalicylideneanilines, and also for N‐benzylideneanilines and N‐salicylideneanilines. The results suggest that the first compounds have a nearly planar conformation whereas the second and third type of derivatives have a twisted conformation.