14N chemical shifts in primary and secondary amides

Abstract

The ¹⁴N chemical shifts in a series of primary and secondary amides have been obtained from the proton spectra by double irradiation techniques. The ¹⁴N shifts in the primary amides are affected only slightly by changes in the substituent on the carbonyl group, but a wider range is found for secondary amides. A qualitative explanation of the observed shift changes is put forward in terms of the effect that the various substituents, have upon the nitrogen lone pair of electrons.