Abstract
The variable temperature (298-179 K)
1
H NMR spectra of
N
-substituted 2-benzazepines (compounds
2
-
7
) correspond to two puckered mirror-image (enantiomorphic) conformations, with a single chair-to-chair interconversion barrier for the benzazepine ring of
ca
. 11 kcal mol
−1
in CD
2
Cl
2
solution. A similar interconversion was detected for 1,3,4,5-tetrahydro-
N
-methylbenzazepine (compound
1
), of lower symmetry. The conformations of compounds
1
-
7
were assigned on the basis of the magnitude of
1
H-
1
H vicinal coupling constants. The
1
H and
13
C NMR spectral assignments were determined by
1
H-
1
H COSY,
1
H-
13
C COSY, and NOESY experiments.