Non‐biaryl atropisomers. part 1. configurationally stable 1,2‐diaryl‐3‐methyl‐1,4,5,6‐tetrahydropyrimidinium salts

In the present communication we describe two examples of a new kind of configurationally stable non‐biaryl atropisomers in which the Ar‐N bond is the chiral axis, namely 1‐(o‐nitrophenyl)‐2‐aryl‐3‐methyl‐1,4,5,6‐tetrahydropyrimidinium iodides 1. Stereochemical features of such compounds are analyzed on the basis of their ¹H and ¹³C one‐ and two‐dimensional nmr spectra. A comparison is made with the corresponding amidines 2 .