Restricted rotation in the NN-dimethylamides of the pyridinecarboxylic acids
Abstract
The free energies of activation at 25 °C for rotation about the amide bond in NN-dimethylbenzamide, and NN-dimethylpyridine-2-, -3-, and -4-carboxamides, have been found to be 61·5, 74·9, 66·6, and 69·5 kJ mol–1 respectively. These values are interpreted in terms of (Jaffé) substituent constants.