Atropisomerism in o-Arylacetyl-N,N-dimethylbenzamides

Article abstract of DOI:10.1021/jo01306a015

A series of o-arylacetyl-N,N-dimethylbenzamides, 1-7, being studied as models for chain tautomers, differed markedly in their 1H NMR spectral properties, as a function of the substituents R₁-R₄.In the two cases where substituents were placed ortho to the amide group, the benzylic protons were anisochronous at ambient temperatures.Reported dynamic 1H NMR results are consistent with concomitant C-N and aryl-CO torsional processes.The 13C carbonyl shifts are compared with those of model compounds.