Abstract
Detailed inspection of the nuclear magnetic resonance spectra of 1, 1a, 6, 10b-tetrahydrodibenzo [b, f] cycloprop [d] azepines (1) in CDCl3 solutions has revealed that the state of conformational equilibrium falls into the following five categories according to the nitrogen substituent Z : 1) There exists a slow equilibrium between conformers I and IV, conformers II and III being either involved in a fast process or not involved at all. 2) Thre eexists a slow (much slower than category 1) equilibrium between conformers I and IV, conformers II and III being either involved in a fast process or not involved at all. 3) Conformer I is the sole one that is present, conformer III being either involved in a fast process or not involved at all. 4) Conformer IV (≡II) is the sole one that is present. 5) There exists a fast equilibrium between conformers I and IV, conformers II and III being either involved in a fast process or not involved at all.
