Exploring potential energy hypersurfaces for triple symmetric inversion in 3-azabicyclo[3.3.1]nonan-9-one and itsN-methyl derivative
✍ Scribed by Smeyers, N. J.; Melendez, F. J.; Smeyers, Y. G.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 298 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
✦ Synopsis
The potential energy hypersurfaces for the triple inversion, from chair to boat and ␣ to  conformations, are explored theoretically in 3w x azabicyclo 3.3.1 nonan-9-one and its N-methyl derivative, by using ab initio quantum-mechanical calculations. Both compounds are precursors of rigid analogs of the potential GABA and GABA receptor antagonists. In contrast to
results from semiempirical calculations, the chair᎐chair  conformers are found to be, by far, the most stable structures for both the nonmethylated and N-methylated compounds. The inversion barriers are found to be relatively low, so that the conformers could be expected to exist in thermodynamic equilibrium at room temperature. A population analysis reveals, however, that, in the ab initio approach, the molecules seem to exist practically only in the chair᎐chair᎐ conformation. The theoretical results compare well with the available experimental data.