SOME STUDIES OF SLOW ROTATIONS AROUND BONDS IN AMIDES

Abstract

Studies were made of the relative rates of rotation around the benzene-to-carbonyl, carbonyl-to-nitrogen, and nitrogen-to-benzene bonds in some α-naphthamides, o-substituted benzamides, and related compounds. In general bulky substituents on the nitrogen atom tend to increase the rate of rotation around the carbonyl-to-nitrogen bond, but to decrease the rate around the benzene-to-carbonyl bond. Naphthanilides with o-substitution in the benzene ring have a rapid rate of rotation around the naphthalene-to-carbonyl bond compared with other naphthamides. Relative rates of rotation can be rationalized on the basis of combined steric and electronic effects.