Nuclear magnetic resonance studies on the configurations and conformations of heterocyclic nitrosamines

Abstract

The nuclear magnetic resonance spectra of various heterocyclic nitrosamines were studied in solution. A qualitative view of the long-range diamagnetic effects of a nitrosamino group is advanced and correlated with the chemical shifts of α-equatorial protons and the methyl group in those nitrosamines possessing a preferred conformation or a rigid system. The use of this correlation to decide the configuration and conformation of heterocyclic nitrosamines is discussed. A large chemical shift difference (ca. 3 p.p.m.) between a cis α-axial and a cis α-equatorial proton was noted.