Nuclear magnetic resonance spectra of azomethines. Part I. Benzylideneanilines

Abstract

N.m.r. spectra of 28 azomethines of the type Ar¹CHNAr² have been measured in deuteriochloroform. Susbtituent and steric effects on the chemical shift of the aldimine proton are discussed. ortho-Substitution in the aldehyde ring has a deshielding effect on this proton whereas ortho-substitution in the amine ring is shielding. The CHN group causes a downfield shift of ca. 0.60 p.p.m. for aromatic protons ortho to the carbon.