Spectroscopic analysis of imidazolidines. Part II: 1 H NMR spectroscopy and conformational analysis of 1,2 and 1,3‐diarylimidazolidines

1 H NMR spectra of a series of 1,2 and 1,3‐diarylimidazolidines are analyzed and correlated with their conformational features. Results were interpreted on the basis of chemical shifts and coupling constants of hydrogen atoms and confirmed by ID nOe difference experiments. 1,3‐Diarylimidazolidines ( 1–7 ) show a fast inversion of the N ‐aryl nitrogen in all studied cases. 1,2‐Diaryl‐3‐methyl (or benzyl) imidazolidines ( 8–13 ) display a preferential conformation with a transoid orientation of N 3 and C 2 substituents.