Spectroscopic studies on N,N-dimethylamides—I: Structure-reactivity correlation for rotational barriers from a nuclear magnetic resonance study of p- and m-substituted N,N-dimethylbenzamides

Rotational barriers in 21 p- and m-substituted N,N-dimethylbenzamides in CDCl₃ as solvent have been determined using the intensity ratio method of Woodbrey. These data compare very well with values from the literature¹ obtained with a total line shape analysis. From structure-reactivity correlations evidence has been obtained for a relatively strong resonance interaction between the substituent in the aromatic ring and the partially double amide bond.